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Imported waste paper and recycled pulp may contain pollutants, posing potential environmental risks to the ecosystem of China. This study examined the presence and distribution patterns of heavy metals, phthalate esters (PAEs), and adsorbable organic halogens (AOX) in recycled pulp and production wastewater after various recycling processes of three typical restricted types of imported waste paper. The results indicated that the concentration ranges of heavy metals, PAEs, and AOX in the three types of imported recycled waste paper were 21.61–40.38 mg/kg, 15.35–27.88 mg/kg, and 19.21–57.72 mg/kg, respectively. The comparative analysis with the initial waste paper demonstrated a reduction in heavy metal content in the recycled pulp by 17.80–49.75%, PAEs by 65.42–90.55%, and AOX by 32.80–42.34%. The average concentrations of these pollutants in wastewater were 0.85–1.66 mg/L, 27.28–59.86 mg/L, and 1.15–3.34 mg/L, respectively. Chromium and lead were identified as the primary heavy metals present in the waste paper. Following pulping, No. 1 and No. 2 met the arsenic and lead levels specified in the "Reuse Fiber Pulp" standard (GB/T24320-2021), whereas No. 3 met these criteria after de-inking only. The main PAEs detected in the waste paper were dibutyl phthalate and di(2-ethylhexyl) phthalate, most of which were removed during the pulping stage. Significantly higher levels of AOX were observed in No. 2 and No. 3 than in No. 1, with a minimal impact on AOX removal from the pulp during the recycling process. [ABSTRACT FROM AUTHOR]

A synergistic photocatalytic system based on Fe-based perovskite with persulfate was constructed for alkali lignin (AL) degradation in pulp and paper wastewater. The degradation performance and mechanism on AL were carried out under ambient temperature and pressure, accompanied by visible light irradiation. The results showed that the synergistic photocatalytic system exhibited much better performance on AL degradation than the single catalytic system. The degradation efficiency reached 73.5% under the optimal conditions and was constant at around 65% over the pH range from 2 to 8. A significant escalation of the AL degradation was observed at pH 10, reaching 80.1%. The photogenerated holes, 1O2 and SO4−·, generated by the system were involved in the degradation, and the holes played a dominant role. During the degradation process, the efficient promotion of cleavage events in lignin methoxy, β-O-4 bond, and benzene ring was observed. Consequently, the depolymerization process led to the generation of high-value compounds, namely p-hydroxybenzaldehyde and vanillin. Remarkably, the yields of the high-value compounds in the synergistic photocatalytic system were five times larger than those in the control. This study offered a viable method to activate persulfate for alkali lignin degradation and to achieve a mutually beneficial strategy for wastewater treatment and recycling. [ABSTRACT FROM AUTHOR]

Green liquor dregs (GLD) is an alkaline by-product from the pulp and paper industry with a pH between 10 and 14. Today most of the produced GLD in Sweden is landfilled. As a fine-grained alkaline material, it might be possible to use it for acid-generating mining waste remediation. To increase the utilization, quality characteristics and environmental performance need to be determined. In this study samples were collected 5 times from 16 mills during a period of 2.5 years, and were characterized by analyzing dry matter content, loss on ignition (LOI) 550 °C and LOI 950 °C, elemental analysis, pH, electrical conductivity, and calorific value. The results were then evaluated using multivariate statistics (PCA) as well as being compared to other studies and Swedish till. The results show that even if GLD is heterogenous (both within a mill and between different mills) trends can be seen for samples from most mills. When samples do stand out, it is predominately related to the same four mills. Most of the studied parameters showed characteristics favorable for use as a remediant; however, TOC, sulfur, and some of the elements require further study. In general, this study concludes that GLD can be a viable option for the remediation of small orphaned sulfidic mining sites and thus worthy of further studies on the interaction between GLD and acidic mining waste. Overall, GLD can be a good alternative for cost-effective remediation of smaller orphaned mining sites. It is readily available in large quantities, has the qualities needed for remediation of many orphaned acidic mining sites, and can often be locally sourced near the mining site. The use of GLD for mining site remediation is likely also a more sustainable method compared to traditional remediation methods. [ABSTRACT FROM AUTHOR]

Paper mill sludge (PMS) is featured with a high content of cellulose and hemicellulose, and using its characteristics to make paperboard can achieve a high-value utilization of PMS, which has attracted growing interest. In this study, currently prevalent landfill, incineration technologies (generating heat and electricity by incineration), and three paperboard technologies (medium density fiberboard, pulp board, and corrugated paper) were evaluated and compared via life cycle assessment (LCA) and life cycle costing (LCC) methods. LCA results show that the PMS-to-pulp board outperforms others with an energy conservation and emission reduction (ECER) value of − 2.86 × 10−8, while the landfill exhibits the highest overall environmental impact with an ECER value of 4.80 × 10−9. LCC results reveal that the PMS-to-pulp board delivers the highest economic profit with $257.357, while the landfill is the lowest with $ − 35.63. The PMS paperboard technologies are more economically friendly than the incineration technologies due to additional electricity/steam consumption during the PMS pre-drying process in incineration. In addition, different scenarios were set up to explore national GHG emission reduction potential by increasing paperboard technologies application rate and reducing the proportion of landfill and incineration. The scenario analysis suggests that replacing 90% of landfill and incineration ratio with PMS paperboard technologies could tremendously improve the overall emission reduction performance with − 9.08 × 1010 kg CO2 eq. This result indicates that the PMS treatment technology transformation has a significant favorable impact on the achievement of the "carbon neutrality" target. [ABSTRACT FROM AUTHOR]

To overcome the human and animal survivability risk, sustainable development is the only option on earth that can be achieved through the maximum use of renewable environmental resources. Recycling of waste paper is an emerging waste management approach to conserve natural resources. Herein, we studied enzyme-mediated process to recycle the xerographic paper by using the crude fungal extract from indigenously isolated fungi identified as Aspergillus assiutensis. The fungal enzyme cocktail has been characterized for the production of multiple enzymes namely cellulase, amylase, xylanase, pectinase, and protease. All these enzymes have pH optima in the acidic range and except cellulase and all the enzymes are stable from 10 to 80 C. In the zymogram analysis, pectinase, xylanase, amylase, and cellulase were detected at 68 kDa, ~ 54 kDa, 38 kDa, and 30 kDa, respectively. Also, the presence of protease was confirmed by the clear zone at 68, 31, and 16 kDa. A 26% decrease in the kappa number and reduction in Hex A of the pulp was observed on the treatment of the pulp with enzyme as compared to the control pulp without any treatment. The physical and chemical properties of the pulp were also improved by enzyme-mediated pulping as compared to the control The physiochemical parameter of the effluent like TDS was reduced (397 ppm) significantly in comparison to chemical deinking process and it was within the permissible limit. BOD and alkalinity were reduced when the enzymes and chemical dosage were used in combination. These results indicate that chemi-enzymatic deinking is most promising to reduce or remove the pollution parameters including ink and this approach can be used in the paper and pulp industry for sustainable development. [ABSTRACT FROM AUTHOR]

Globally, per- and polyfluoroalkyl substances (PFAS)–related research on paper products has focused on food packaging with less consideration on the presence of PFAS at different stages of the paper recycling chain. This study analysed the prevalence of PFAS in paper grades used for the manufacture of recycled paperboard. The presence of PFAS was attributed to the use of PFAS-containing additives, consumer usage, exposure to packed goods as well as contamination during mingling, sorting, collection, and recovery of paper recycling material. Q Orbitrap mass spectrometry was used to analyse the paper samples after accelerated solvent extraction and solid phase extraction. The distribution and possible propagation of 22 PFAS were determined in pre-consumer, retail and post-consumer paper products. Post-consumer samples had the highest combined average concentration (ΣPFAS) at 213 ng/g, while the ΣPFAS in retail (159 ng/g) and pre-consumer samples (121 ng/g) was detected at lower concentrations. This study showed that waste collection and recycling protocols may influence PFAS propagation and that measures must be developed to minimise and possibly eliminate exposure opportunities. [ABSTRACT FROM AUTHOR]

The production of paper is a key component for global civilization. Around 300 million tonnes of paper are produced every day globally, with matured pulpwood being the major contributor. Due to rising demand for paper and the depletion of available wood resources, researchers are now focused on finding alternative non-wood resources that are suitable for pulp and paper production. The current study aims to produce eco-friendly and biodegradable paper using a combination of Eichhornia crassipes (water hyacinth) and dried flowers. Water hyacinth is considered as a lignocellulose plant which contains 57% lignocellulose, and dried flower contains 40% cellulose, which is the prime source for paper production. Various sections of water hyacinth, including wet and dry petiole, leaves, and root, were blended with dried flowers through the soda process. Then, the physical properties and FTIR analysis was carried out to identify the quality of the paper produced. The paper produced from root and dried petiole has a lower thickness (1.0 mm and 0.5 mm) than other mix proportions. The opacity of the leaves was found to be 0.5% (light passing) and for the root 0.7% (light passing). Also, the dry petiole and root paper have a good dry tensile strength of 1.30Kpa and 1.20Kpa, respectively. Hence, paper made from dry petiole and root was found to be efficient and suitable for the paper industry. [ABSTRACT FROM AUTHOR]

The environmental and energy impacts of ICT were identified using a comparative life cycle assessment (CompLCA) focused on business invoicing processes comparing online to paper processes. There were net energy benefits from online billing. The potential impact across the economy and society is large, particularly as COVID-19 has forced many businesses and government services to shift to online service provision. For one million bills produced electronically and received by customers instead of a paper bill, 18.9 t CO2e is avoided, which translates to a national saving of 22,680 tCO2e, assuming 1.2 billion annual invoicing transactions. The impacts of CO2 are sensitive, however, to several assumptions. The study's originality was to show the range of invoicing variables that impact energy and the environment and to highlight which ones can be influenced. For example, the number of online bills produced was the most sensitive. However, the results are reversed under commonly occurring customer use situations. The study demonstrates the positive and negative impacts from the digitalisation of businesses. It suggests remedies based on the main drivers identified under company, contractor and customer control that led to energy consumption and environmental and land use impacts. [ABSTRACT FROM AUTHOR]

Recycled paper pulping wastewater (RPPW) will cause serious environmental problems due to the high loads of dissolved organic matter (DOM) and toxic components. In the present work, the degradation of DOM in the biologically treated RPPWs (cardboard wastewater (CW) and corrugated container wastewater (CCW)) by a combined coagulation and ozonation process was investigated. The optimal chemical oxygen demand (COD) removal of CW reached 73.64% at aluminum sulfate (Al2(SO4)3) dosage of 800 mg/l, aeration aperture of 10 μm, pH of 9, hydrogen peroxide (H2O2) dosage of 100 mg/l, and reaction time of 70 min. The optimal COD removal of CCW reached 55.76% at a poly-aluminum chloride (PAC) dosage of 700 mg/l, H2O2 dosage of 140 mg/l, and reaction time of 50 min. This study provided some insights into the change of DOM during the combined treatment through the use of UV–Vis spectroscopy and excitation-emission matrix spectroscopy (EEM). PAC and Al2(SO4)3 removed high molecular weight organic such as lignin and lignin-derived compounds to improve the biodegradability of the wastewater. Ozone oxidized high molecular weight organic with complex functional groups to low molecular weight organic with simple functional groups and even mineralization, and this phenomenon resulted in the COD of ozonation effluent significantly reduced. Thus, the results presented in this study support the application of the combined coagulation and ozonation process in treating RPPW. [ABSTRACT FROM AUTHOR]

Toilet paper has been reported as one of the major insoluble pollutant components in the influent of wastewater treatment plants. Toilet paper fibers contribute to a large production of sewage sludge, resulting in a high treatment cost and high energy consumption. To find energy-efficient, cost-effective, and environment-friendly technologies for fiber removal and resource recovery from wastewater, a life-cycle assessment (LCA) was performed to analyze the wastewater treatment processes, including a sieving process for removing and recovering suspended solids before the biodegradation units. Based on the LCA results, it was estimated that the sieve screening process saved 8.57% of energy consumption. The construction phase of sieving consumed 1.31% energy cost compared with the operation phase. Environmental impact analysis showed that sieving reduced the impacts of climate change, human toxicity, fossil depletion, and particulate matter formation, which reduced the total normalized environmental impacts by 9.46%. The life-cycle analysis of the removal of toilet paper fibers from wastewater revealed the need to use more efficient methods to enhance the recovery of cellulose fibers. [ABSTRACT FROM AUTHOR]

China's pulp and paper industry (CPPI) has been always the main carbon emission source in recent years. However, the analysis on influencing factors of carbon emissions from this industry is insufficient. To address the issue, the CO2 emissions from CPPI are estimated in the period of 2005–2019, the driving factors of CO2 emissions are investigated by the logarithmic mean Divisia index (LMDI) method, the decoupling state of economic growth and CO2 emissions is determined by Tapio decoupling model, and finally, future CO2 emissions are predicted under four scenarios by the STIRPAT model to explore the potential of carbon peaking. The results show that CPPI exhibits a rapid increase and a fluctuating downward trend in CO2 emissions during the period of 2005–2013 and 2014–2019, respectively. The main promoting and inhibiting factors to the increase of CO2 emission are per capita industrial output value and energy intensity, respectively. There are five decoupling states of CO2 emissions and economic growth during the study period, and the CO2 emissions exhibit a weak decoupling state with the industrial output value growth in most years of the study period. It is very difficult to realize the carbon peaking goal by 2030 under the baseline and fast development scenarios. Therefore, efficient low carbon and strong low-carbon development policies are necessary and urgent for the realization of carbon peaking goal and the sustainable development of CPPI. [ABSTRACT FROM AUTHOR]

In the 2030 Agenda for Sustainable Development, adopted by the United Nations (UN) member states in 2015, half of the target period has been exceeded. However, China, whose energy consumption relies heavily on fossil resources, remains at the top of the list of global polluters. Therefore, investigating the environmental impacts of energy types is essential to China's path towards Sustainable Development Goals (SDG)-7 and SDG-13. Based on this motivation, the paper offers new insights into the energy-environment literature for China with wavelet coherence analysis (WCA). This approach can investigate the relationship between variables in a periodic manner based on the frequency behavior of the models. The paper separately analyzes the effects of primary energy consumption (PEC), fossil energy consumption (FEC), renewable energy consumption (REC), nuclear energy consumption (NEC), GDP, and population (POP) on three different environmental indicators in China. Using two environmental pollution indicators (carbon emission (CO2) and ecological footprint (EF)) and one environmental quality indicator (load capacity factor (LCF)), the paper allows for comparison and robustness checks on the environmental impacts of energy indicators. Empirical findings reveal the following: (i) Except for REC and POP in the CO2 model, the variables in all three models largely move together during the period under observation; (ii) variables other than POP have consistent coefficient signs; (iii) PEC, FEC, NEC, and GDP increase CO2 and EF while decreasing LCF; (iv) the effect of NEC on LCF is more obvious until 2000; (v) unlike the others, REC affects CO2 and EF negatively and LCF positively; (vi) there is bidirectional causality between PEC and environmental indicators but not for REC; (vii) the causality relations of other variables with environmental indicators differ in terms of model, time, and direction of causality. In light of the findings, the paper highlights that only the REC improves environmental quality in China. Other energy indicators contribute to environmental degradation. China, whose ecological deficit has increased dramatically in recent years, urgently needs to reduce its dependence on fossil energy sources by accelerating investments in REC. Governments should also review nuclear energy policies, which are expected to help achieve carbon neutrality. [ABSTRACT FROM AUTHOR]

To ensure the safety of food contact materials, a liquid chromatography method was established to determine the migration of formaldehyde in paper packaging with various food simulants (10%, 25%, 50%, 75%, and 95% ethanol by volume) and to investigate the migration behavior of formaldehyde after various durations and with various materials. The results showed that the method has good linearity with a correlation coefficient of R2 > 0.9990, a detection limit of 0.0011 ~ 0.0027 mg L−1, and a spiked recovery of 89.7 ~ 103.2% in the range of formaldehyde determination; the migration of formaldehyde in all six paper contact materials showed a trend of gradual increase with time until equilibrium was reached. At the same time and temperature, the migration of formaldehyde in paper packaging was the highest in low-concentration ethanol. With the same food simulants and materials, the maximum migration of formaldehyde in printed materials was greater than that in nonprinted materials; with different materials and the same food simulant, the thickness value was higher, with the use of water-based ink as a printing material, and the maximum migration value of formaldehyde by offset printing technology was low. [ABSTRACT FROM AUTHOR]

Paper for recycling has become a promising raw material for the pulp and paper industry due to its low cost and because it is conducive to sustainable development. Unfortunately, recycled paper contains a high volume of printed paper that is difficult to deink, which restricts its applications. Flotation deinking plays an essential role in the product quality and process cost of wastepaper recycling. This study was performed to evaluate the deinkability of environmentally friendly offset inks by flotation deinking. For this purpose, three mineral oil free series of four-color inks, namely, hybrid light emitting diode ultraviolet (LED–UV), LED–UV, and vegetable oil-based inks, were printed on white lightweight coated papers under laboratory conditions. The deinking methodology involves repulping, deinking agent treatment, flotation, hand sheet making, and evaluation of the produced hand sheets. The obtained results indicated that the hybrid LED–UV prints had the best deinkability. After flotation deinking, the deinking efficiency and the whiteness of the hybrid LED–UV ink increased by 58.1% and 47.6%, respectively. LED–UV ink had a 46.9% increase in the deinking efficiency and a 37.0% increase in the whiteness of the hand sheet. The deinking efficiency of the vegetable oil-based ink was the lowest, at 42.1%, and the whiteness of the hand sheet increased only by 23.8%. The particle size distribution analysis demonstrated that the hybrid LED–UV four-color ink exhibited a larger value of the average particle size than the two other. Scanning electron microscopy revealed that the hybrid LED–UV ink particles on the surface of the fibers were the least abundant after deinking. The physical strength properties of the hand sheets, including tensile index, folding resistance, and interlayer bonding strength of the hybrid LED–UV, LED–UV inks, and vegetable oil-based inks, increased. [ABSTRACT FROM AUTHOR]

In this study, TiO2 nanoparticle (TiO2NP)-coated film was produced to protect manuscripts against microorganisms using ecofriendly benign materials. As a result, a simple method was created that uses poultice biofilm made of carboxymethyl cellulose (CMC) and Phytagel plant cell (PGP) loaded with TiO2NPs to preserve manuscripts against microbes in an environmentally responsible way. Three volumes (1, 2, 4 mL) of TiO2NPs were put into a biofilm combination to produce the poultices known as CMC/PGP/TiO2-1, CMC/PGP/TiO2-2, and CMC/PGP/TiO2-3. The synthesized TiO2NPs were nearly spherical in shape, small in size (98 nm), and stable (zeta potential value − 33 mV). The results showed that the unique deposition of TiO2NPs on the biofilm surface gave the produced films loaded with TiO2NPs a rough structure. The highest values of mechanical characteristics were determined to be in CMC/PGP/TiO2-1 with values of 25.4 g, 6.6 MPa, and 11.4%, for tensile strength, elongation at break, and tear strength, respectively. Based on molecular identification, the fungus Aspergillus sydowii and the bacterium Nevskia terrae, with accession numbers MG991624 and AB806800, respectively, were isolated and identified from an antiquated manuscript formed from cellulosic fibers. Before the experiments, the produced cotton paper samples were aged, and then, one group was infected for 6 months by A. sydowii and the second group with N. terrae. Following the preparation of a CMC/PGP biofilm loaded with various volumes of TiO2NPs, poultices were applied to infected cotton paper in order to clean it. The infected cotton paper was placed inside the sandwich-like poultices that were created. The poultice CMC/PGP/TiO2-2 demonstrated potential for preventing the growth of A. sydowii and N. terrae-infected cotton paper, when the fibers were saved, cleaned, and coated with CMC/PGP/TiO2-2 after absorbing the fungus and the bacterium and exhibiting exceptional antimicrobial activities. Finally, the novel biofilms have demonstrated their capacity to lessen microbial contamination of cotton paper. In order to generalize the usage of these poultices, it is also advised that they be produced on a large scale and tested on a variety of organic materials in the future. [ABSTRACT FROM AUTHOR]

The present study aimed to understand microplastic (MP) ingestion by five fish species with different feeding habits namely, Schizothorax richardsonii and Crossocheilus latius (herbivore),Cyprinus carpio (omnivore), Tor chelenoid (herbi-omnivore), and Botia horii (carnivore). The fishes were sampled from River Alaknanda (one of the headwaters of River Ganga) patch at Srinagar, Garhwal, Uttarakhand. The fish gut samples were digested with 30% hydrogen peroxide and vacuum filtered through glass microfiber filter. Each filter paper was observed microscopically to count MPs, and then, selected MPs were chemically characterized using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR). The results revealed that all the species were contaminated with MPs and the rate of MP ingestion varied with feeding habits. The herbi-omnivore fish, Tor chelenoid, was observed to have the highest MP ingestion. Among the analyzed particles, fibers (66%) were the dominant type of MPs. The MPs were chemically characterized as High-Density Polyethylene (HDPE), Polypropylene (PP), and Polyester. This study contributes as a reference for the forthcoming researches, as it is the pioneer work on the ingestion of MP by fishes of a Himalayan River. [ABSTRACT FROM AUTHOR]

The circular economy is emerging as an economic form to solve economic, environmental, and social problems around the world. In this regard, various countries and regions of the world are making every effort to establish and implement circular economy strategies and action plans. This paper discusses the Recycling Law adopted in the Democratic People's Republic of Korea and its characteristics. To this end, this paper examines the cases of legalization in various countries and regions around the world related to the circular economy and recycling and explains the contents and characteristics of the Recycling Law in the Democratic People's Republic of Korea concerning it. The findings are that (a) the more science and technology develop and the more complete the economic structure becomes, the more complete the legal environment related to the circular economy should become and (b) if the transition to the circular economy is to be implemented with strong obligations, the planning lever must be regulated as a legal obligation, and the state needs to use the planning lever to thoroughly implement circular economy-related goals and strategies. These findings can be used as a reference to prepare a legal environment for promoting the circular economy in countries pursuing the realization of a circular economy in a top-down way, and it will also help fill the gap in research on the legal environment for promoting the circular economy. [ABSTRACT FROM AUTHOR]

Reducing carbon emissions and improving energy efficiency are essential to respond to global climate change actively. However, improving energy security under resource and environmental constraints is the key for China to achieve high-quality and sustainable development. Thus, using the panel data at the enterprises and regional levels in China from 2013 to 2020, this research develops an energy security index to study the impact of the short-selling mechanism on energy security. The results show that China's energy security is generally on the rise under the short-selling mechanism. However, it has different degrees of impact on energy security in different energy structures, supply chains, and environments. In addition, China's energy security has a regional spillover effect under the short-selling mechanism's capital pressure and supervision governance. This paper also finds that short-selling can alleviate the supply chain's bullwhip effect and risk effect. Finally, the short-selling mechanism complements the micro-influence mechanism of energy security, and short-selling positively impacts China's energy security. [ABSTRACT FROM AUTHOR]

Existing literature ignores to consider multiple types of pollutants when analyzing energy efficiency and its convergence. Under this background, using SuperSBM-GML model, the improved entropy method, and convergence model, this paper calculates the green total-factor energy efficiency and its evolution trend of 35 China's industrial sub-sectors considering multiple pollutants, and analyzes its convergence. The results indicate that the average score of industrial green total-factor energy efficiency is low, and there are significant differences among sub-sectors: "Utilization of waste resources" is the highest, while "Manufacture of paper and paper products" is the lowest. The green total-factor energy efficiency shows an overall upward trend from 2006 to 2021, the main driving force comes from technological progress, but numerous sub-sectors have not sufficiently caught up with existing cutting-edge technologies. Specifically, the growth rate of green total-factor energy efficiency in high-energy-consumption sub-sectors is higher than low-to-medium-energy-consumption sub-sectors. There are both σ-convergence and β-convergence in low-to-medium-energy-consumption group, indicating that development of sub-sectors is stable and outstanding. Nevertheless, the high-energy-consumption group only exhibits conditional β-convergence, revealing an imbalance in energy efficiency development. Consequently, formulating the benchmark level of energy efficiency and developing energy efficiency "leader" system are suggested for low-to-medium and high-energy-consumption sub-sectors, respectively. [ABSTRACT FROM AUTHOR]

Municipal waste management is a major challenge for local governments in South Africa and Namibia, as in other developing countries. The circular economy concept in waste management is an alternative sustainable development framework that has the potential to combat resource depletion, pollution, and poverty while achieving the SDGs. The purpose of this study was to investigate the current waste management systems in Langebaan and Swakopmund municipalities resulting from municipal policies, procedures, and practices in the context of a circular economy. A mixed method approach was used to collect qualitative and quantitative data through structured in-depth interviews, document analyses, and direct observation. The study found that the Langebaan and Swakopmund municipalities have not yet fully implemented the circular economy concept into their waste management systems. A mix of waste consisting of papers, plastics, cans, tyres, and organic products is dumped into landfills weekly at a rate of about 85%. The main challenges to implementing the circular economy concept include: lack of technical solutions, inadequate regulatory frameworks, insufficient financial resources, lack of private sector involvement, insufficient human resource capacity, and inadequate information and knowledge. A conceptual framework was therefore proposed to guide the municipalities of Langebaan and Swakopmund in implementing the circular economy concept in their waste management systems. [ABSTRACT FROM AUTHOR]

Improving carbon emission efficiency is crucial for achieving carbon peak and carbon neutrality. This paper analyzes the carbon emission efficiency of Chinese cities using panel data from 275 prefecture-level cities between 2006 and 2020. The super-efficiency SBM (undesirable slacks-based measurement) model of undesired output, combined with kernel density estimation and exploratory data analysis, is employed. This study finds, firstly, from 2006 to 2020, the average efficiency of carbon emissions in Chinese cities declined from 0.53 to 0.48, indicating a downward trend. Secondly, from a temporal perspective, the level of dispersion in urban carbon emission efficiency has become increasingly distinct over time, coupled with a decrease in polarization. Thirdly, in terms of spatial analysis, urban carbon emission efficiency in China shows a positive correlation in a global context. In terms of local spatial correlation, it primarily exhibits high-high and low-low clusters, with a few instances of low–high and high-low clusters. Finally, based on the research findings, this paper proposes suggestions to improve urban carbon emission efficiency. [ABSTRACT FROM AUTHOR]

The digital finance generated by technology empowerment profoundly affects the innovative behavior of micro-enterprises. To estimate how digital finance influences the quantity and quality of green technological innovation, this paper introduces digital finance into endogenous economic growth model and further conducts correlation analysis with the combination of fixed effects model (FE) and panel threshold model (PTM). Moreover, this paper investigates the action mechanism from the perspective of financial constraint and financial cost. The empirical results indicate that digital finance improves the quantity and quality of green technological innovation significantly. Compared with the coverage of digital finance and digital services, the impact of usage depth on green innovation accumulates dynamically superimposed in the long term. The digital finance contributes to correct the mismatch of financial resources and further induces inclusive green innovation in the dimension of ownership, growth cycle, and enterprise scale. Mechanism analysis shows that the relief of financial constraint, environmental information disclosure, and increase of R&D investment are the main paths for digital finance to drive green innovation. With the different thresholds, the dynamic evolution process of green innovation driven by digital finance is characterized by "first quantitative change and then qualitative change." This paper suggests that the integration of technological innovation and digital financial services needs to build an inclusive digital financial service system, cultivate diversified financial formats, and improve the market environment of digital financial services. [ABSTRACT FROM AUTHOR]

This paper presents the global research landscape and scientific progress on occupant thermal comfort in naturally ventilated buildings (OTC-NVB). Despite the growing interest in the area, comprehensive papers on the current status and future developments on the topic are currently lacking. Hence, the publication trends, bibliometric analysis, and systematic literature review of the published documents on OTC-NVB were examined. The search query "Thermal Comfort" AND "Natural Ventilation" AND "Buildings" was designed and executed to recover related documents on the topic from the Elsevier Scopus database. Results showed that 976 documents (comprising articles, conference papers, reviews, etc.) were published on the topic from 1995 to 2021. Further analysis showed that 97.34% of the publications were published in the English language. Richard J.de Dear (University of Sydney, Australia) is the most prolific researcher on OTC-NVB research, while Energy and Buildings has the highest publications. Bibliometric analysis showed high publications, citations, keywords, and co-authorships among researchers, whereas the most occurrent keywords are ventilation, natural ventilation, thermal comfort, buildings, and air conditioning. Systematic literature review demonstrated that OTC-NVB research has progressed significantly from empirical to computer-based studies involving complex mathematical equations, programs, or software like artificial neural networks (ANN) and computational fluid dynamics (CFD). In general, OTC-NVB research findings indicate that physiological, social, and environmental factors considerably influence OTC in NVBs. Future studies will likely employ artificial intelligence or building performance simulation (BPS) tools to examine relationships between OTC and indoor air/environmental quality, human behavior, novel clothing, or building materials in NVBs. [ABSTRACT FROM AUTHOR]

Digital inclusive finance eases credit constraints on innovative small and medium-sized enterprises which contributes to urban green technology innovation in China. Government intervention plays an essential role in the development of digital inclusive finance. Based on the panel data of 243 cities in China from 2011 to 2019, this paper empirically examines the relationship between digital inclusive finance and urban green technology innovation as well as the intrinsic mechanism of government intervention. The findings show that, even after a series of robustness tests, digital inclusive finance can promote the quantity and quality of green technology innovation. In terms of its mechanism, digital inclusive finance can empower green technology innovation by complementing traditional financial development and stimulating green consumption, both in terms of supply and demand. At the same time, in the dynamic process of digital financial inclusion from low to high, the development of traditional finance and green consumption level on the marginal promotion of green technology innovation continues to strengthen. The nonlinear relationship test reveals that there is a significant double threshold effect on the positive impact of digital inclusive finance on urban green technology innovation with the evolution of government intervention. The innovation incentive effect of digital financial inclusion will be marginal decreasing with the increase of government intervention. Further considering the heterogeneity of urban geographic location and environmental regulation, it is found that digital financial inclusion promotes green technology innovation more in eastern and high-environmental regulation cities. Based on the above research conclusions, this paper argues that while developing digital inclusion finance, government support policies should be adjusted promptly to constantly stimulate the "Metcalfe's law" effect of digital inclusive finance enabling green technology innovation. [ABSTRACT FROM AUTHOR]

This paper explores the impacts of industrial collaborative agglomeration on industrial sulfur dioxide intensity from a spatiotemporal perspective based on panel data on the 284 prefecture-level cities from 2003 to 2019, with systematic consideration of the underlying mechanism of channels and actions. The empirical results show that industrial co-agglomeration significantly intensifies industrial SO2 intensity, especially with increasing agglomeration. In addition, its positive spatial spillover effects are established in geographical proximity to the city. Furthermore, the channel analysis shows that the industrial structure path, industrial efficiency path, and industrial scale path account for a sharp increase in industrial SO2 intensity. The market forces reverse and moderate this exacerbating process more significantly than the government does, which provides evidence for the importance of pursuing a dynamic equilibrium between them. Finally, there exist heterogeneous effects across cities with different administrative levels, innovation capacities, and macropolicies of special emission limits for air pollutant policy. While arguing for the environmental pollution effects of industrial co-agglomeration, this paper also provides solid support and a new perspective for promoting sustainable economic development and achieving win–win economic and environmental benefits. [ABSTRACT FROM AUTHOR]

The quest for cost-effective and thermal efficient structural materials onto beating the high cost of construction is gaining more attention among researchers. This study focused on the blending of cement and sand with waste paper pulp into cost-effective structural materials. The composites were prepared in four mix groups with each containing a fixed amount of sand at 5, 10, 15, and 20 wt.% (by weight of pulp). Cement was varied at 10, 20, 30, and 40 wt.% in each group, and curing was done for 28 days. Properties evaluated are compressive, bending, and splitting strengths. It was observed that increasing cement and sand contents enhanced strengths; howbeit, the blend of 30 wt.% cement/15 wt.% sand resulted in a reduction in bending strength even as 30 wt.% cement/20 wt.% sand engendered a decrease in bending and splitting strength. The microstructural features showed that inherent fibers of the pulp were well bonded with hydration products and sand content yielding good performance in the composites. The optimization procedure carried out depicted a combination of 35.27% cement and 20% sand as the optimum composition. Experimental outcomes were modelled for the purpose of prediction of responses. The models were confirmed statistically fit showing how varying cement content affected strength responses at fixed sand proportion. ANOVA affirmed the significant contribution of cement and sand on the strength responses. Compliance reliability was observed to be dependent on the interactive pattern between cement and sand. Going by the standard prescription for the strength properties, cement and sand content of 35.27 and sand 20 wt.% satisfied all strength requirements for low-cost construction having a compliance reliability of 1.31. [ABSTRACT FROM AUTHOR]

Carbon dioxide mineral carbonisation is a means to achieve permanent carbon dioxide storage, this paper to solid waste materials as the main raw material to prepare fly ash-based carbon dioxide storage materials. Through the design of carbon dioxide adsorption experimental setup to study the main factors affecting the adsorption capacity of the fly ash-based storage materials, the experimental results show that, the fly ash mass fraction decreased from 90 to 10%, the water-cement ratio increased from 0.4 to 0.8 when the CO2 adsorption of fly ash-based materials increased by 82% and 30%, respectively. The effect of strong alkali on CO2 adsorption capacity was also investigated in this paper, and the results showed that the CO2 adsorption of the fly ash-based material sample with 10 ml NaOH added increased by 197% compared with that of the sample with 5 ml NaOH added, whereas the adsorption amount was reduced by 85% when 25 ml NaOH was added instead, which was attributed to the accelerated hydration process of the material due to the excessive alkalinity that consumed the calcium and magnesium ions in the material, and at the same time the production of hydration products hindered the transport of CO2 within the material, which led to a decrease in CO2 adsorption. [ABSTRACT FROM AUTHOR]

Nowadays, the paper industry supplies its required fibers either from primary fibers, including wood and plants, or waste papers, called secondary fibers. One of the most challenging recycling processes is deinking of papers digitally printed with electrophotographic ink. In order to produce optically high-quality paper from recycled waste papers, deinking step is required at the desired levels. In this work, the environmentally friendly green enzymatic deinking of printed paper was modeled and optimized via an innovative approach called artificial intelligence method. The effect of treatment temperature, treatment time, and enzyme dosage on mechanical properties (tensile and burst strengths) as well as optical properties (whiteness and brightness) of handsheet was investigated. The developed code can appropriately learn the non-linear behavior of deinking process, and make decisions according to the pattern constructed intelligently. Finally, multi-objective optimization at the specified treatment temperature, treatment time, and enzyme dosage was performed to identify the best conditions for enzyme-deinked handsheet (maximized mechanical and optical properties). [ABSTRACT FROM AUTHOR]

Since its discovery, carbon quantum dots (CDs) have been widely applied in cell imaging, drug delivery, biosensing, and photocatalysis due to their excellent water solubility, chemical stability, fluorescence stability biocompatibility, low toxicity, and preparation cost. However, the low fluorescence yield and poor surface structure limit the application of CDs. Heteroatom doping is considered an ideal method to improve CDs' optical and electrical properties. From this perspective, eco-friendly biomass and its derivatives are perfect carbon precursors for CDs because they contain the heteroatoms needed to modify CDs, and their complex chemical composition gives CDs a wide variety of surface functional groups. Besides, converting biomass waste into high-value-added CDs is also an innovation in biomass waste treatment. Therefore, this paper focuses on the carbon precursors of biomass CDs. At the same time, food packaging occupies an essential position in the industry, and fluorescent CDs with good fluorescence properties, high chemical stability, and good photobleaching properties have great application potential in packaging innovation techniques that have emerged in recent years, but relevant reports are scarce and scattered. Considering that the surface morphology, chemical structure, and optical and electrical properties of biomass CDs are primarily affected by the carbon precursors' chemical structure and preparation method, this paper also focuses on the synthesis method of biomass CDs and its application in anti-counterfeiting packaging, intelligent packaging, antioxidant packaging, and antibacterial packaging. [ABSTRACT FROM AUTHOR]

Goiânia, the Goiás State capital, starred in 1987, where one of the largest radiological accidents in the world happened. A teletherapy machine was subtracted from a derelict radiotherapy clinic and disassembled by scavengers who distributed fragments of the 50 TBq 137CsCl source among relatives and acquaintances, enchanted by the blue shine of the substance. During the 15 days before the accident was acknowledged, contaminated recycling materials were delivered to recycling factories in four cities in the state of São Paulo, Brazil, in the form of recycling paper bales. The contaminated bales were spotted, collected, and stored in fifty 1.6 m3 steel boxes at the interim storage facility of the Nuclear and Energy Research Institute (IPEN). In 2017, a check of the content was performed in a few boxes and the presence of high moisture content was observed even though the bales were dry when conditioned and the packages were kept sealed since then. The main objective of this work was to report the fungi found in the radioactive waste after they evolved for 30 years in isolation inside the waste boxes and their role in the decay of the waste. Examination of the microbiome showed the presence of nematodes and fungal communities. The fungi species isolated were Aspergillus quadricinctus, Fusarium oxysporum, Lecanicillium coprophilumi, Scedosporium boydii, Scytalidium lignicola, Xenoacremonium recifei, and Pleurostoma richardsiae. These microorganisms showed a significant capacity to digest cellulose in our trials, which could be one of the ways they survive in such a harsh environment, reducing the volume of radioactive paper waste. These metabolic abilities give us a future perspective of using these fungi in biotechnology to remediate radioactively contaminated materials, particularly cellulose-based waste. [ABSTRACT FROM AUTHOR]

Microorganisms are a promising source of colorants with large economic potential. Owing to better bio-degradability and higher eco-compatibility, microbial pigments propose promising avenues and can thus be a smart substitute for artificial pigments. The present work focused on the screening, isolation, and extraction of a blue-green pigment produced by soil microorganisms. The pigment-producing microorganism was identified as Pseudomonas aeruginosa on the basis of standard biochemical tests and by 16S rRNA sequencing. The purified blue pigment was characterized by high-performance liquid chromatography and gas chromatography–mass spectrometry. The antimicrobial activity of the microbial biocolor (3 × 108 CFU/ml) was studied, and the zone of inhibition was found to be 10 mm, 13 mm, 9 mm, and 7 mm for E. coli, S. aureus, B. subtilis, and S. typhi, respectively. The evaluation of the biocolor as a dye was executed on different types of textiles and paper. The dyed fabrics were checked for washing, rubbing, and light and temperature fastness. Standard fabric properties of the fabrics dyed with the extracted microbial pigment were also assessed. The dyed fabrics were finally subjected to a patch test to check for any kind of allergic or hypersensitivity on human skin. The extracted pigment from Pseudomonas aeruginosa exhibited remarkable dyeing properties, indicating the scope for utilization of the pigment as a colorant on different types of textile and paper materials. The present study highlights the application of a bacterial pigment as a dyeing agent, which may raise its market value and probably replace toxic synthetic dyes due to its nontoxic nature, compatibility with various textiles, and cost-effectiveness. [ABSTRACT FROM AUTHOR]

Developing countries primarily rely on fossil-based energy sources to meet their energy demands. The use of fossil fuels has several adverse environmental repercussions that damage the biosphere both directly and indirectly. Among fossil fuels, coal brings about the heaviest environmental externalities, yet its abundance makes its use widespread, particular in countries having significant power generation deficits, such as Pakistan. This study presents an environmental, technological, and economic analysis of a supercritical coal-based power unit located in Pakistan and used for electricity generation. For environmental assessment, the CML-1A baseline method in OpenLCA software was used, and eight midpoint impact indicators were selected. The functional unit chosen was 1 MWh of generated electricity. The results indicated that the category of ozone layer depletion has the least impact, whereas global warming potential has the highest impact score. Except for photochemical oxidation and human toxicity, the plant operational stage dominated most of the selected impact categories. The current paper also reveals that the removal efficiency of CO2 and other pollutants is higher in supercritical compared to subcritical plants. Moreover, the economic feasibility of supercritical plant is compared with chemical looping combustion (CLC)-based supercritical coal-fired power plant, and results shows that CLC-based coal-fired power plant is a more competitive and environmentally friendly option. The utilization of a scientific cleaner energy-management system in real-time, as exemplified in this study, may facilitate the development of a optimal policy framework that encourages for the adoption of cleaner coal power generation in developing countries, ultimately resulting in improved energy sustainability. Furthermore, this paper also presents some policy implications which could be helpful for policymakers, researchers, and industrialists to improve the sustainability of energy in emerging economies. [ABSTRACT FROM AUTHOR]

Industrialization plays a crucial role in socio-economic development as it holds significant potential for creating new jobs, tightening the income gap, and promoting the use of advanced technology. As global competition intensifies, emerging economies emulate industrialized economies in accelerating manufacturing activity to improve national welfare and join the new global order. However, policymakers' understanding of how competitiveness in the industrial sector helps developing countries accomplish their sustainable development goals must be deepened. This paper aims to analyze the connections among competitive industrial performance, renewable energy consumption, urbanization, and load capacity factor (LCF) in the BRICS economies for the period between 1990 and 2018. Robust evidence from the continuously updated fully modified (CUP-FM) and continuously updated bias-corrected (CUP-BC) models shows that greater industrial competitiveness enhances environmental quality. The findings also reveal that income growth ultimately evolves as an ecologically friendly factor, confirming the validity of the load capacity curve (LCC) hypothesis. Another outcome of the econometric analysis indicates that renewable energy consumption contributes to the LCF, whereas urbanization damages the environment. Therefore, BRICS policymakers should concentrate on maintaining their competitiveness, implementing resilient urban planning, and promoting the usage of renewable energy to safeguard the environment while simultaneously achieving rapid economic growth. [ABSTRACT FROM AUTHOR]

Carbon and pollution reduction are highly synergistic elements of green development, and the detailed derivation of the synergistic relationship is urgently needed. Based on the research perspective of coupling coordination, this paper firstly bases on the research perspective of coupling synergy, takes 30 provinces in China as the research object from 2011 to 2022, and constructs a coupling coordination degree model to measure the synergistic effect of pollution reduction and carbon reduction; secondly, kernel density and Dagum coefficient are used to analyze the spatial and temporal characteristics, spatial differences and sources of differences in the synergistic effects of pollution reduction and carbon reduction in China as a whole, in the three major regions and in each province; finally, the Moran index is applied to test the spatial agglomeration characteristics of the synergistic effect of pollution reduction and carbon reduction, and the spatial panel model is applied to test its β-convergence. The study shows that (1) during the study period, the level of synergistic effect on carbon reduction in China changed from good coordination to good coordination, and the synergistic effect in the western region was significantly better than that in the eastern and central regions; (2) the synergistic effect of pollution reduction and carbon reduction in China as a whole and the three regions showed obvious spatial differences, but the differences were gradually narrowing, and the supervariable density was the dominant factor of the overall differences; (3) as a whole, the synergistic effect of pollution reduction and carbon reduction among provinces has a spatial agglomeration effect, and the level of synergistic effect of pollution reduction and carbon reduction across the country and east and west regions has a significant absolute β convergence trend, while there is a significant conditional β convergence trend across the country and the three major regions, and the eastern and central regions with a low synergy level have a higher convergence rate, indicating that as time goes by, under the influence of various factors, the synergistic effect will converge to the steady state level. The purpose of this paper is to analyze the spatial patterns and regional differences in the synergistic effects of pollution reduction and carbon reduction in Chinese provinces and also to provide a quantitative basis for the full implementation of the synergistic regulation of pollution reduction and carbon reduction. [ABSTRACT FROM AUTHOR]

The European Union (EU) has taken several initiatives over the past two decades to harmonize environmental taxation policies across member countries. The directive on energy taxation (Directive 2003/96/EC) provides the framework for the taxation of energy products within the EU. These harmonization efforts are part of a broader strategy to ensure environmental sustainability and combat climate change. This paper examines whether these efforts have had any impact on the convergence of environmental taxation across EU countries during the period 1995–2021. This paper uses a new panel unit root test that accounts for cross-correlations and structural breaks within the panel since regulations on taxation increase the possibility that EU countries may have commonalities on these issues. The club convergence test is also used to test for the existence of multiple equilibria within groups of countries. The results of the traditional convergence test show that environmental tax revenues are converging across EU countries. Furthermore, the results of the stochastic convergence test indicate that there is a convergence of relative environmental tax revenues. As for the break dates, the results from the tax revenue series show that the first and second break are concentrated in the periods 2002–2007 and 2012–2017, respectively. Finally, the results of the club convergence test reject the full panel convergence and reveal the existence of different convergence clubs. The empirical results of this paper have some implications for environmental taxation in the EU. [ABSTRACT FROM AUTHOR]

A promising water treatment method involves using biomass-derived activated carbon (AC) to remove emerging pollutants from wastewater due to its adsorption capacity, cost-effectiveness, and sustainability. Notwithstanding, the existing literature lacks comprehensive studies that specifically focus on removing contaminants in water by comparing the effectiveness of adsorption and photocatalytic degradation methods. Additionally, there is not much emphasis on analyzing the combined processes of adsorption-photocatalytic degradation utilizing AC. Herein, this paper investigates the intricacies of adsorption-photocatalytic degradation mechanisms and contributing variables in the enhancement of performances using biomass-derived AC. Furthermore, this review paper presents a comprehensive examination of different biomass sources employed in the synthesis of AC. It also discusses the diverse techniques utilized for the fabrication of AC, including physical and chemical activation methods. Finally, the shortcomings and future prospects of biomass-derived AC have been addressed. This study offers significant insights for the development of future biomass-derived AC, with the goal of improving their efficiency and expanding their uses in wastewater treatment. [ABSTRACT FROM AUTHOR]

Waste management is the protection of the environment and the health of the population. Paper waste sludge is produced during paper production and sepiolite is a natural clay mineral. The aim of the study was to investigate the usability of sepiolite-added paper waste sludge as a bedding material in the broiler production. Two hundred eighty-eight 1-day old male broiler chicks were divided into the 6 bedding material groups (wood shavings (control), paper waste sludge, sepiolite, mix of 25% paper waste sludge and 75% sepiolite, mix of 50% paper waste sludge and 50% sepiolite, and mix of 75% paper waste sludge and 25% sepiolite) with 6 replicate pens per group. Litter quality, performance, and some welfare parameters of broilers were assessed during the 6 weeks' period. Body weight at 42 days of age and body weight gain from 0 to 42 days of broilers reared on the wood shavings and mix of 50% paper waste sludge and 50% sepiolite were found higher than those of the sepiolite and paper waste sludge groups. Feed consumption and feed to gain ratio from 0 to 42 days, yields of carcass and carcass parts, percentages of organs and abdominal fat, IgG, percentage of bursa Fabricius, burns of foot pad and breast, litter pH and meat properties of broilers reared on the wood shavings, paper waste sludge, and sepiolite litter groups were not found to be statistically different. Litter moisture was found higher in the paper waste sludge group than that in the sepiolite group at the 42 days of rearing. As a conclusion, usage of mix of 50% paper waste sludge and 50% sepiolite as a litter does not have any negative effects on performance, welfare, and litter quality. This result is important in terms of utilizing a waste product. [ABSTRACT FROM AUTHOR]

In this work, the effect of using Ag-doped TiO2 nanopigments on optical, mechanical and antimicrobial properties of coated paper was explored. Furthermore, the long-term antimicrobial activity of the coated paper was examined for up to 25 years. Titanium dioxide (TiO2) nanoparticles have been synthesized and doped with different percentages of Ag nanoparticles (Ag NPs) using a simple wet chemical approach. The Ag@TiO2 modified nanopigments were in the form of nanorods with an average size of about 20 nm as observed from TEM images. Increasing Ag content from 0.01 to 1.0% showed an increase in the mechanical properties of coated paper in terms of tensile, stretching, tensile energy absorption and burst while preserving the optical properties. Moreover, the antimicrobial inhibition activity increased with increasing the Ag content. The 1% Ag@TiO2 showed a long-lasting antimicrobial effect against Staphylococcus aureus (S. aureus) Gram-positive bacteria even after 25 years of ageing (93.4% inhibition). Investigation of reactive oxygen species (ROS) generation and reaction mechanism of antimicrobial activity over Ag/TiO2 under visible light is proposed. These results suggest that Ag/TiO2 NPs can be potentially used as a disinfection coating for paper and improving its mechanical properties. [ABSTRACT FROM AUTHOR]

The potential of alkaline cellulo-xylanolytic enzymes from non-pathogenic Bacillus subtilis strain was tested for deinking of photocopier waste paper. Cellulase and xylanase play a crucial role in deinking of different types of waste paper. Partial purification of cellulo-xylanolytic enzymes was carried out using ultrafiltration followed by ammonium sulfate precipitation. The ultrafiltered enzyme was used for deinking the photocopier waste paper along with chemical deinking. An enzyme dose of 0.6 IU/g and reaction time of 60 min for ultrafiltered cellulo-xylanolytic enzyme significantly increased deinking efficiency, tear index (9.52%) and folding endurance (5±2%) as compared to chemical deinking. There was improvement in strength properties such as tear index and double-fold along with freeness of pulp (18%). There was slight decrease in tensile index (0.6%) and burst index (16%) while ISO brightness remained unaffected. Enzymatic deinking (74.3%) by ultrafiltered cellulo-xylanolytic from Bacillus subtilis was found significant over conventional chemical deinking. [ABSTRACT FROM AUTHOR]

An essential requirement for colorimetric paper-sensor is to allow the target analytes (heavy metal ions) to access the chromophore while maintaining strong chromophore immobilization on the porous substrate surface. This work evaluates the selection of sensitive chromophores (dithizone, 1-(2-pyridylazo) 2-naphthol and 4-(2-pyridylazo)-resorcinol) and their immobilization strategies on paper sensors. Dithizone (DTz) are capable of producing a significant color transition at unadjusted pH, observed by UV–Vis absorption spectroscopy and visible recognition. After immobilizing DTz on a paper substrate (cellulose acetate/chitosan substrate), the DTz-paper sensor showed a distinctive color change from blue-green to peach-pink upon reaction with Pb2+ ions, and the color intensity was proportional to the metal concentration. Quantitative analysis using RGB (R:Red; G:Green; B:Blue) plots showed that increasing DTz concentration on the CA/CS paper sensor increases the difference in total color intensity (∆IT) and the difference in red code intensity (∆IR). This is due to the formation of more DTz-Pb2+ complexes on the CA/CS paper substrate. The CA/CS paper strips immobilized with 100 ppm DTz showed practical potential for rapid detection of heavy metal ions. The DTz-CA/CS paper sensor showed significant color change when detecting spiked heavy metals ions (0.1 ppm Pb2+, 2.0 ppm Zn2+, and 0.2 ppm Cu2+) in river water samples that prepared at the maximum permissible limit for industrial effluent in Malaysia. [ABSTRACT FROM AUTHOR]

Analyzing the spatiotemporal characteristics and driving mechanisms of the coupling coordination between the Green Transition of Urban Land Use and urban land use efficiency can help explore the future development direction of sustainable land use in cities. This paper constructs a theoretical framework for the coupling coordination between Green Transition of Urban Land Use and urban land use efficiency. We use several models, including the super-efficiency slack-based model, the coupling coordination degree model, the non-parametric kernel density estimation method, exploratory spatial data analysis, and the geographically and temporally weighted regression model to examine the real level of Green Transition of Urban Land Use and urban land use efficiency in the Yangtze River Delta region from 2003 to 2020. Based on this, we investigate the spatiotemporal evolution characteristics and driving mechanisms of the two coupling coordination processes. The study found that (1) from 2003 to 2020, the overall trend of the coupling coordination between Green Transition of Urban Land Use and urban land use efficiency in the Yangtze River Delta region tended to be coordinated and developed, but still at a primary coordination level, with sufficient room for improvement in the future. (2) The coupling coordination level of each city in the Yangtze River Delta region from 2003 to 2020 showed obvious spatial non-equilibrium and correlation characteristics, and overall dynamic polarization effects were exhibited during the study period; the spatial pattern of high-value areas showed a regularity of prioritizing Shanghai and Zhejiang Province, gradually penetrating into Jiangsu Province and Anhui Province. (3) Economic and social factors have a positive influence on the degree of coupling coordination; natural factors and policy factors have a predominantly negative influence on the degree of coupling coordination. Research conclusions include establishing a regional collaborative development mechanism, utilizing the spatial spillover effect of leading cities; emphasizing science, education, and culture, strengthening the introduction of scientific and technological talents, increasing fiscal inputs, raising the level of economic development, and further expanding the driving effect of economic and social factors; and optimizing the layout of urban and rural construction land, developing urban land in an orderly manner, appropriately strengthening environmental regulation, thereby suppressing the negative effects caused by natural and policy factors. [ABSTRACT FROM AUTHOR]

Drawing on the textual contents of the Chinese local government work reports, this paper focuses on the impact of leading officials' audits of natural-resource assets on the local environmental attention allocation. The study has found that during the pilot period of audits, compared with the non-pilot cities, the local government in the pilot cities has concentrated more on the ecological environment field and has placed greater emphasis on the actual environmental governance. The results of mechanism analysis show that differences in the personal and take-office characteristics of local officials, may lead to different promotion pressure and performance evaluation modes, and then have a different impact on local environmental attention. The test results of consequence analysis show that the environmental attention in the pilot cities can be further transformed into environmental administrative and financial governance behavior. The paper discusses the policy effect and internal mechanism of leading officials' audits of natural-resource assets from the perspective of local governments' environmental attention, providing empirical evidence for China to carry out the top-level design of environmental policy based on the idea of optimizing officials' performance evaluation mechanism. [ABSTRACT FROM AUTHOR]

So far, urban scaling theory has proven that urban area, infrastructure, and economic output have a scaling relation with population. But if we consider ecological space as a part of urban infrastructure, would the same scaling characteristics exist? What is the scaling relationship between ecological spaces and economic social development in different stages of urbanization? This paper is based on this question and explores the trade-off between social economic system and ecosystem in 370 cities of China. The results show that the relationship between population and urban ecological space generally follows the scaling theory in terms of different types of ecological spaces and ecosystem services. For every 10-fold increase in population size, the total area of ecological space and ecosystem services increase by approximately 4 times. The manifestation of ecological space following the scaling laws is the aggregation behavior of better network connectivity. There is a trade-off between urban ecological space and socioeconomic development, with flow equilibrium reached at a population of 2 million and efficiency equilibrium reached at a population of 1 million. Starting from type I and type II megapolis, urban development gradually tends to stabilize, and there may even be a trend of slow decline in urban development potential. In the absence of ecological space, virtual network space can serve as a substitute for ecological space. The driving factors affect scaling behavior of ecological space, including connectivity of ecological space, spatial heterogeneity of natural conditions, and disturbance of economic and social activities. This research can help city to expand ecological space, promoting the added value of urban ecological assets and keeping the urban development potential within the optimal threshold range continuously. [ABSTRACT FROM AUTHOR]

Establishing a reasonable cost-sharing and compensation mechanism for air pollution control is a prerequisite for realizing inter-regional cooperative treatment. Taking inter-provincial sulfur dioxide (SO2) emissions in China from 2005 to 2019 as the research object, this paper proposes a data-driven approach to establish a cost-sharing index system of regional SO2 treatment in four dimensions and construct a cost-sharing and compensation scheme using the entropy-TOPSIS method. The results revealed that there are significant spatial and temporal differences in the treatment cost of SO2 emission, and the total SO2 treatment costs at the national level increased first and then decreased during the study period, meanwhile, the regional SO2 treatment costs are much higher in the less economically developed regions such as the central and western regions than in economically developed eastern coastal regions. The design of the cost-sharing and compensation mechanism of SO2 treatment should consider the regional differences in abatement capacity, abatement potential, abatement responsibility, and development demands. The economically developed regions should share higher treatment costs according to their historical cumulative abatement responsibilities, and provide economic compensation and technical support to the less economically developed regions. Specifically, the marginal abatement cost in the more economically developed eastern region is much higher than that in the less economically developed central and western areas due to their large abatement responsibility and strong reduction capacity but insufficient abatement potential, so the eastern regions can transfer part of their abatement responsibility to the central and western regions using economic compensation. Reasonable cost sharing and horizontal compensation can help promote regional cooperation and synergistic management in air pollution abatement. Finally, corresponding policy recommendations are given to provide a decision basis for cross-regional cooperation in air pollution control. [ABSTRACT FROM AUTHOR]

Microplastics (< 5 mm) have lately been identified in the atmosphere of urban, suburban, and even distant places far from plastic particle areas, suggesting the possibility of long-distance atmospheric transport of microplastics. However, the occurrence, fate, transmission, and effects of these suspended atmospheric microplastics (SAMPs) are all currently unknown in the Philippines. This study investigated the presence of suspected microplastic in the atmosphere of sixteen cities and one municipality of Metro Manila, Philippines. Sampling was conducted using a respirable dust sampler mounted with a Whatman GF/C filter paper at an intake flow rate of 1.4 L/min with Whatman GF/C filter paper. Results reveal that all seventeen sampling areas have the presence of SAMPs. A total of 155 SAMPs were found and confirmed in Metro Manila, with the highest concentration in Muntinlupa City and Mandaluyong City (0.023 SAMP/NCM). Fourteen SAMP types were identified across the sampling areas, ⁓ 74% with polyester. This study is the first record of the presence of microplastics suspended in the ambient air in the Philippines. It is estimated that an adult person in Metro Manila has the potential to inhale (5–8 per minute, normal minute ventilation) about 1 SAMP if exposed for about 99.0 to 132 h. Further studies should be done to evaluate the fate and health effects of these SAMPs in Metro Manila's setting. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic forced use of face masks up to billions of masks per day globally. Though an important and necessary measure for control of the pandemic, use of masks also poses some inherent risks. One of those risks is inhalation of microplastics released from the mask materials. Since most of the mask materials are made from plastic/polymers, they always have the potential to expose the user to fragmented microplastics. To estimate the amount of inhalable microplastic exuded from masks, an experiment simulating real-life scenario of mask usage was performed. The study included collection of microplastics oozed out from the masks on to a filter paper followed by staining and fluorescence detection of the total number of microplastics using a microscope. Both used and new masks were studied. Based on the emission wavelength, the microplastics were found to be belonging to three different categories, namely blue, green and red emitting microplastics respectively. The number of microplastic particles emitted per mask over a period of usage of 8 h was about 5000 to 9000 for new masks and about 6500 to 15,000 for used masks respectively. The estimation of polymer type of plastic in the mask fabrics was also carried out using Raman and FTIR spectroscopy. [ABSTRACT FROM AUTHOR]

This paper consists of the evaluation in regards to the ecotoxicological effectiveness of a treatment applied to a coal mining waste. The treatment consisted of separating the particles based on gravimetric concentration in spirals, generating three fractions: heavy, intermediate, and light, with high, moderate, and low pyrite content, respectively. The intermediate fraction represents the larger disposal volume of the waste on soils. To evaluate the effectiveness of the treatment, metal determination and bioassays Eisenia andrei, Folsomia candida, Lactuca sativa, Daphnia similis, and Raphidocelis subcapitata were applied to the intermediary fraction. To evaluate the toxicity to aquatic organisms, elutriates were generated from the unprocessed waste and the intermediate fraction. The intermediate fraction showed a decrease of metal concentrations compared to the untreated waste. Metal concentrations in the intermediate fraction were below the Brazilian thresholds for soil quality. Avoidance bioassay with E. andrei and germination tests of L. sativa showed no significant effects. The bioassay with F. candida indicated a significant reduction in reproduction at the highest doses used (24% and 50%). Bioassays with D. similis and R. subcapitata revealed a reduction in toxicity of the intermediate fraction compared to the untreated waste. However, the toxicity levels of the intermediate fraction to aquatic organisms still require attention, especially in regards to pH that played a crucial role in the toxicity. Finally, the results suggest that the treatment performed on the coal waste was efficient, even though significant toxicity have still been detected in the treated waste and additional steps are still required for adequate final disposal. [ABSTRACT FROM AUTHOR]

The maritime sector plays a key role in transportation in the world, and over 90% of world trade is carried by ocean shipping. However, ships are large contributors to global emissions. Hence, a vast majority of research publications have focused on different emission monitoring techniques, which are essential to establishing required policies and regulations that reduce maritime transport emissions. Various documents have been published on monitoring maritime transport emissions affecting air quality since 1977. This paper presents a bibliometric analysis to explore evolution trends, gaps, challenges, and productive countries, as well as the most cited publications with high scholarly impacts. The annual growth of 9.64% in publications demonstrates an increasing interest in reducing maritime vessel emissions. Journal articles constitute 69% of publications, followed by conference papers (25%). China and the USA play a leading role in this field of research. Regarding active resources, the "Atmospheric Environment" journal accounts for the highest relevant publications, H-index, and total citations. Eventually, the temporal evolution of keywords shows the increasing trend towards sustainable maritime transport. [ABSTRACT FROM AUTHOR]

The uses of natural dyes are getting popularized due to the increased awareness regarding the toxicity of many chemical colorants. The chemical colorants are being replaced by the natural colorants for the various industrial applications. The plant-based natural colorants are considered eco-friendly and toxic free. In the present study, we report a natural dye from the heartwood of Caesalpinia sappan suitable for paper based packing materials. This forms the first report on the study of natural dye obtained from the heartwood of C. sappan on paper material. The extracted dye had a good photostability and able to make imprints on recycled paper bags. Moreover, a significant inhibition of bacterial growth was observed at a higher dye concentration of 100 μg mL−1 against P. aeruginosa which was higher than the standard antibiotics. Growth inhibition was also observed in case of B. subtilis (22 ± 0.17 mm) and K. pneumonia (21 ± 0.53 mm) at 100 μg mL−1. The dye could be used in making medicated packing materials and have many other bio-potential which was validated through in silico toxicity analysis. The application of such natural dyes in paper material value addition will help in a cleaner and sustainable process during paper recycling. [ABSTRACT FROM AUTHOR]

Low pressure reverse osmosis (LPRO) has been increasingly used in advanced treatment of pulp and paper wastewater (PPWW) for the purpose of water reuse. However, membrane fouling is a major problem encountered by full-scale RO systems due to the organic and inorganic contents of the feedwater. Electrocoagulation (EC) as an effective treatment for foulants removal can be applied in pre-filtration. Therefore, the LPRO membrane fouling mechanism and the membrane fouling control performance by EC treatment were investigated in this study. EC pretreatment could reduce the membrane fouling and improve the membrane flux by 31%, by effectively removing and/or decomposing the organic pollutants in PPWW. Fluorescent spectrometry analyses of the feedwater and the permeate revealed that humic acid-like and fulvic acid-like organics in PPWW were the major foulants for the LPRO membranes. Fourier transformation infrared spectrometry results confirmed that the organic foulants contained benzoic rings and carboxylic groups, which were typical for organic substances. EC effectively removed organic pollutants containing functional groups such as carboxylic acid COH out-of-plane bending, olefin (trans), and NH3+ symmetrical angle-changing. Moreover, the extended Derjaguin-Landau-Verwey-Overbeek model suggested that the membrane filtered 30-min EC-treated PPWW had the strong repulsion force to foulants due to the higher cohesion energy (12.1 mJ/m2) and the lower critical load, which theoretically explained the reason of EC pretreatment on membrane fouling control. [ABSTRACT FROM AUTHOR]