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The increased production and expanding demand for cellulosic products have required companies to provide solutions for the proper disposal of generated residues without compromising soil quality. In this context, the current research aimed at evaluating the ecotoxicological impacts of dregs application in subtropical soils. The experiments were carried out with the earthworm Eisenia andrei, the springtail Folsomia candida, and the potworm Enchytraeus crypticus in two subtropical soils (Neosol and Cambisol) collected in the southern region of Brazil. The considerable differences in texture and organic matter content motivated the choosing of these soils. The reproductive rate of all organisms was influenced, with varying EC 50 values depending on the soil type. However, more pronounced effects were observed for Neosol. The springtail F. candida proved to be the most sensitive to contamination (EC 50  = 5.8 g kg -1 for Neosol and 48.5 g kg -1 for Cambisol), followed by the earthworm E. andrei (EC 50  = 62.4 g kg -1 for Neosol and 129.5 g kg -1 for Cambisol) and the potworm E. crypticus (EC 50  = 67.2 g kg -1 for Neosol and 230.4 g kg -1 for Cambisol). As a result, while dregs can be used to correct soil acidity, they have been shown to have negative effects on important organisms responsible for functions critical to maintaining ecosystem quality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Non-targeted analysis and suspect screening of per- and polyfluoroalkyl substances (PFAS) in various matrices have gained traction with advancements in accurate mass analytical instruments. This study employed ultra-high performance liquid chromatography coupled to quadrupole orbitrap high-resolution mass spectrometry for PFAS suspect screening of paper grades used in the paper recycling chain. The samples were prepared using two extraction techniques; selective accelerated solvent extraction with weak anionic exchange solid-phase extraction and non-selective ultrasonic-assisted extraction. A suspect screening protocol was established to tentatively identify suspected PFAS against spectral databases using a systematic approach of peak filtering and study-specific thresholds for reporting, linked to a confidence level. The possible prevalence of previously unreported PFAS in several paper materials across the various collection sites in the paper recycling chain was inferred by the common detection of short-chain polyfluoroalkyl ketones and diketones in the paper recycling chain. The suspect screening tentatively identified 41 unique PFAS, with 3 common to both pre-treatment techniques. The detection of unique PFAS by the two sample pre-treatment techniques highlighted the significance of both selective and non-selective extraction in PFAS screening endeavours. Further, it showed the importance of understanding the acquisition mechanisms employed in mass spectrometry where data-dependent acquisition triggered fragmentation in certain identified compounds, and not in others. The tentatively identified PFAS indicated that there were several previously unreported PFAS in the paper recycling chain and that additional studies were required to investigate their abundance, possible persistence, bioaccumulation and toxicity, in relation to their functional groups and carbon chains., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Nondumiso Mofokeng reports funding was provided by Mpact Operations Pty (Ltd). All other authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

The present study employed powdered activated coke (PAC) for the adsorptive removal of refractory COD from the bio-treated paper wastewater (BTPW). The adsorption reached equilibrium after 3 h, resulting in a decrease in the COD concentration from 98.9 mg L -1 in BTPW to 42.6 mg L -1 when utilizing a PAC dosage of 5 g L -1 . The dominant fractions of dissolved organic matter in BTPW were hydrophilic acids (HIA), hydrophilic neutrals (HIN), and hydrophobic acids (HOA), accounting for 48.8%, 34.2%, and 17.0% of the total dissolved organic carbon, respectively. Three fractions were all predominantly composed of humic/fulvic acid-like substances, while the HOA fraction exhibited highest susceptibility to adsorption by PAC, followed by the HIA and HIN fractions. FT-ICR MS data revealed PAC preferentially adsorbed the unsaturated and oxygen-rich substances containing more carboxyl groups. Additionally, the spent PAC was regenerated through ozonation and subsequently utilized in the adsorption cycles. The regeneration was successfully conducted under an ozone concentration of 1 mg L -1 for a duration of 10 min, and the regeneration efficiency remained about 87.0% even after undergoing five-cycle of adsorption-regeneration. The findings of this study demonstrate that PAC adsorption is a viable and efficacious treatment technology for efficiently removing refractory COD from BTPW., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The large use and emission of p-nitrophenol (p-NP) seriously pollute the environment and endanger human health. In this work, a hydrazone-linked fluorescent covalent organic framework (BATHz-COF) was simply synthesized at room temperature and covalently linked N-acetyl-L-cysteine (NALC) via the "thiol-ene" click reaction, where carboxyl groups were introduced to improve dispersion and fluorescence intensity. As a rapid, good selectivity and reusability fluorescence sensor, the obtained COF-NALC has been used for quantitative analysis of p-NP predicated on the internal filtering effect (IFE). Under optimal conditions, COF-NALC enabled quantitative detection of p-NP with a linear range of 5-50 μM and the detection limit was 1.46 μM. The application of COF-NALC to the detection of p-NP in river water samples was successful, and the satisfactory recoveries were 98.0%-109.3%. Furthermore, the fluorescent COF paper chips constructed by in situ growth were combined with a smartphone to build a visual platform for the quick and real-time detection of p-NP, providing an excellent illustration for the development of intelligent fluorescence sensing in environmental analysis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

The reuse of waste papers by conversion into valuable carbon materials has received considerable attention for diverse applications such as energy storage and water purification. However, traditional methods for converting waste papers into materials with suitable properties for specific applications are often complex and ineffective, involving consecutive carbonization and activation steps. Herein, we propose a simple one-step microwave (MW)-assisted synthesis for preparing waste paper-derived porous carbons (WPCs) for energy storage and water purification. Through a 30-min synthesis, WPCs with graphitic structure and high specific surface area were successfully produced. The fabricated WPCs exhibited outstanding charge storage capability with a maximum specific capacitance of 237.7 F g -1 . Additionally, the WPC demonstrates a high removal efficiency for various dyes, achieving a maximum removal efficiency of 95.0% for methylene blue. The developed one-step MW synthesis not only enables the production of porous carbon from waste paper, but also offers a viable approach to address solid waste management challenges while simultaneously yielding valuable materials., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The deinking in the paper industry is in great demand, and microbial enzymes are key players. In the present study, the endoglucanase production from newly isolated fungi Aspergillus niger MPS25 is reported. The optimization of endoglucanase production was carried out using one factor at a time approach resulting in endoglucanase activity (2.37 IU/ml) at 45 °C and pH 8 in submerged fermentation (SmF), which shows optimum enzyme activity at 60 °C. Interestingly, the metal ions viz. Co 2+ stimulated the endoglucanase activity, whereas Mn 2+ reduced the enzyme activity, which shows that this enzyme can be used for effluent treatment released through deinking. The enzymatic hydrolysis of wheat straw produced 26.96 ± 0.108 mg/g of reducing sugars, indicating its potential in saccharification and the biofuel industry. Furthermore, the validation of the deinking efficiency of this enzyme resulted in improved deinking of mixed office waste and old newspapers by 31.5% and 20.4%, respectively. The strength properties, viz. burst factor and tear index, breaking length, and tensile index of the handmade paper sheets, were also improved which were analyzed by the scanning electron micrographs. The FTIR and XRD analysis of pulp provided insights into the changes in functional groups and cellulose crystallinity, respectively. These results indicate that multi-efficient endoglucanase from Aspergillus niger MPS25 is suitable for enzyme-based eco-friendly deinking for waste paper recycling and lignocellulosic biomass saccharification., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Aim of this research was to treat the organics enriched Paper and Pulp Industry (PPI) effluents using multi-metal tolerant predominant indigenous bacterial species. In addition, assessing the potential of treated bacterial biomass as a single cell protein (SCP). The multi-metal tolerant Streptomyces tuirus OS1 was enumerated from the Paper and Pulp Industry (PPI) effluents was identified through standard molecular characterization. S. tuirus OS1 proficiently ameliorated organic contaminants in PPI effluent in the in study at 35 °C, 45 °C, and 25 °C. Fortunately, the S. tuirus OS1 considerably increased the dissolved oxygen level in treated PPI effluent in 30 days of bioremediation process. Interestingly, at 35 °C of bioremediation process the S. tuirus OS1 demonstrated increased dried biomass (7.1 g L -1 ) with the total crude protein (SCP) as 5.3 g L -1 (78.79%) in 30 days of bioremediation process. These findings suggest that S. tuirus OS1 is capable of reducing organic pollutants in PPI effluents and producing biomass with enriched protein content., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Due to the presence of various organic contaminants, improper disposal of pulp-paper wastewater poses harm to the environment and human health. In this work, pulp-paper sludge (PPS) after secondary treatment were collected from M/s Century Pulp-paper Mills in India, the chemical nature of the organic pollutants was determined after solvent extraction. All the isolates were able to produce lipase (6.34-3.93 U ml -1 ) which could account for the different fatty acids detected in the PPS. The dominant strains were in the classes of α and γ Proteobacteria followed by Firmicutes. The Shannon-Weiner diversity indexes for phylotype richness for the culturable and non-culturable bacterial community were 2.01 and 3.01, respectively, indicating the non-culturable bacterial strains has higher species richness and diversity compared to the culturable bacterial strains. However, the culturable strains had higher species evenness (0.94 vs 0.90). Results suggested only a few isolated strains were resistant to the POPs in the PPS, where as non-cultural bacteria survived by entering viable but non-cultural state. The isolated strains (Brevundimonas diminuta, Aeromonas punctata, Enterobacter hormaechei, Citrobacter braakii, Bacillus pumilus and Brevundimonas terrae) are known for their multidrug resistance but their tolerance to POPs have not previously been reported and deserved further investigation. The findings of this research established the presence of POPs which influence the microbial population. Tertiary treatment is recommended prior to the safe disposal of pulp paper mill waste into the environment., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The landfilling of paper mill sludge (PMS) has been restricted or even banned in many countries due to the raised concern about greenhouse gas (GHG) emissions and contamination of the soil and water, calling for a sustainable PMS management approach. The potential valorization of PMS to nanomaterials combined with traditional biorefinery was examined in this work. Three types of PMS-derived cellulose nanofibrils (CNFs) were prepared and evaluated: enzymatically assisted CNF (AU: with in-house produced enzyme and CT: with commercial enzyme), mechanically pretreated CNF (BT), and chemically pretreated CNF by TEMPO oxidation (TEMPO). It was found that enzyme-assisted mechanical fibrillation-derived CNFs had a comparable average diameter (27.9 nm for AU and 22.7 nm for CT) with that produced from mechanical pretreatment (26.5 nm for BT) and TEMPO oxidation pretreatment (20.0 nm for TEMPO), and they showed the best drainage properties among the three types of CNF. The CNFs resulting from enzymatic pretreatment reduced 15% of energy consumption compared to the mechanical method and had better thermostability than TEMPO oxidation method. In addition, the on-site produced enzyme showed similar performance to the commercial enzymes towards the CNF properties. These findings provide new insights into a promising integrated strategy in engineering CNF from PMS with on-site enzyme production as a novel and sustainable approach for PMS management and valorization., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Heavy metals released by anthropogenic activities are extremely toxic to animals and plants due to their bioaccumulative and persistent environmental presence. In the current study, silver nanoparticles (AgNPs) were synthesized utilizing eco-friendly processes, and their potential in colorimetric Hg 2+ ion sensing in environmental samples was examined. An aqueous extract of Hemidesmus indicus root (Sarsaparilla Root, ISR) rapidly converts silver ions into AgNPs within 5 min of exposure to sunlight. Transmission electron microscopy confirms that ISR-AgNPs are spherical, ranging from 15 to 35 nm. Fourier-transform infrared spectroscopy revealed phytomolecules stabilized the NPs with hydroxyl and carbonyl substituents. The ISR-AgNPs detect Hg 2+ ions by a colour change that can be seen with the naked eye within 1 min. The probe is interference-free and detects the presence of Hg 2+ ions in sewage water. A method for fabricating ISR-AgNPs onto paper was disclosed, and this portable ISR-AgNPs embedded paper device was found to be good at sensing mercury present in the water. The findings show that environmentally friendly synthesized AgNPs can contribute to developing onsite colorimetric sensors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Paper has become the basic elixir in everyone's activities and usage of paper has increased day by day, the waste generated by paper is also enormous. The primary source of paper is wood (tree) yet, waste paper is environmentally good and biodegradable; however, it is the primary source of deforestation. Current research aims to find an alternate way to recycle paper in the biological approach. Hence in our work, twelve cellulose-producing bacteria were isolated, out of which one bacterial strain proved to be the best. Cellulase enzyme was extracted and purified, and used for enzymatic de-inking of photocopy papers. The optimal conditions for cellulase synthesis were at 60 °C, glucose as the only carbon source, and potassium nitrate as the nitrogen source. The enzyme demonstrated excellent de-inking at a lower pulp consistency of 3% with a 20% enzyme dose. The cellulose and hemicellulose levels decreased, which can be attributed to fiber breaking. Further, the changes in the functional groups identified by Fourier-transform infrared spectroscopy analysis and the changes in the surface morphology of the pulp fibers were obtained using scanning electron microscope analysis., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Hypochlorous acid (HClO) and derivative ionic form (ClO - ) are significant components of reactive oxygen species, and thus various diseases are correlatively related to the concentration of ClO - . Recently, paper-based indicators have been confirmed to be efficient strategy for sensing hazardous and noxious substances. However, most of these materials can only achieve qualitative detection of the substrates. Herein, an extremely simple manufacturing strategy was proposed to convert commonly-used paper into nano-engineered fluorescent biomass-based platform (CMJL-FP) integrated with on-demand self-assembled colorimetric and ratiometric fluorescence sensor (CMJL) for rapid ClO - quantitative detection in organisms or water sources using smartphones. The CMJL exhibited a highly selective and sensitive ratiometric response to ClO - at a low detection limit (LOD = 92.6 nM). The associating interactions between the fluorescence nano-particles and micro-nano fibers of CMJL-FP ensure good-stability during ClO - detection. It has been experimentally demonstrated that CMJL-FP allows one to realize the rapid quantitative detection of ClO - ions in living cells and large-scale water sources by using color recognition software as part of a simple smartphone. Therefore, integrating the proposed fluorescent paper with smartphones provides an effective, sustainable, cheap and conceptual strategy for quantitative detection of hazardous and noxious substances in organisms and environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The article presents the research results of the oxidation of watered toxic waste from the pulp and paper industry (sludge-lignin, the empirical formula of organic matter CH 1.51 N 0.05 S 0.03 Cl 0.01 O 0.54 ) in supercritical water-oxygen (SCW/O 2 ) fluid. The experiments were carried out using a flow tube reactor at a pressure of 25 MPa, temperature gradient along its vertical axis (from top to bottom: 390-600 °C), sludge-lignin flow rate of 9.5-14.5 g/min, oxygen ratio OR = 0.73-2.52, using NaOH (1.6 wt%) as a catalyst. Employing gas chromatography - mass spectrometry, polychlorophenols were identified in the composition of sludge-lignin, in which 2,4,6-trichlorophenol was the main component. The total yield of extracted phenols and chlorophenols per sludge-lignin organic matter was 20.82 and 2.88 μg/g, respectively. It is revealed that the conversion rate of sludge-lignin in SCW/O 2 fluid is limited by heterogeneous oxidation of the carbonized residue, and is determined by the O 2 content in the reaction mixture. At OR ≥ 1.16, only CO 2 , CO, N 2 , and N 2 O were detected in the volatile oxidation products. An increase in OR from 0.73 to 2.52 leads to a decrease in the total content of phenols (from 45540.1 to 129.3 μg/dm 3 ) and chlorophenols (from 51.4 to 2.2 μg/dm 3 ) in the water collected at the reactor outlet. It is shown that 2,6-dichlorophenol and 2-chlorophenol are the most resistant to oxidation. From the analysis of the initial sludge-lignin and mineral residues, it follows that the bulk of the chlorine contained in its organic matter is converted into NaCl in the course of oxidation., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

As a typical advanced oxidation process, Fe 2+ -persulfate (PDS) oxidation technology has been widely and efficiently reported for enhancing sludge dewaterability. However, higher dosage of Fe 2+ must be added, which will restrain the oxidation efficiency of Fe 2+ -PDS process. In this work, the oxalic acid (OA)/Fe 2+ -PDS process was studied to improve paper sludge dewatering. With the OA dosage of 6 μmol (g total solid (TS)) -1 , Fe 2+ dosage of 0.3 mmol (g TS) -1 , and PDS dosage of 0.6 mmol (g TS) -1 , sludge dewaterability was improved more efficiently. The specific resistance to filtration and water content of sludge cake were decreased by 70.7% and 8.0%, respectively. In comparison with Fe 2+ -PDS process, the viscosities of sludge suspension and supernatant were further reduced by 3.73% and 51.77%, respectively, and the contents of extracellular polymeric substances fractions were increased. The improved sludge dewaterability in OA/Fe 2+ -PDS process was mainly contributed by the synergistic effect of oxidative disintegration by free radicals and flocs re-flocculation, the contributions of which were the orders: metal cations > sulfate radical > hydroxyl radical. OA enhanced the efficient disintegration of sludge flocs, released more bound water, generated more Fe 3+ -oxalate complexes, and finally increased the sludge particle size significantly, forming a larger aggregation and obvious cracks. Additionally, the stabilization of several heavy metals was improved due to the chelating capacity of OA. These works will provide a novel approach for sludge dewatering in the PDS oxidation process., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

A laboratory scale (LS) and a field-based pilot plant (PP), designed to simulate aerobic stabilization basin (ASB) operation, were utilized to assess the potential impacts of changes in pulp and paper (P&P) mill operations on full-scale (FS) ASB performance. Two stages of investigation were conducted. The first was undertaken to determine the potential of pre-alum treatment of pulp mill wastewaters on ASB performance. The second investigation was conducted to assess ASB performance where wastewaters transitioned from being coagulated pulp and paper mill wastewaters to paper mill wastewaters only. Simulation ASB performance was assessed based on removals of BOD 5 , colour, UV@254 nm and nutrients [total phosphorus (TP) and nitrogen compounds (TN)]. Pre-alum treatment of pulp mill wastewaters with subsequent ASB treatment following mixing with paper mill wastewaters showed high percentage removals of BOD 5 . Despite low TP concentrations (≤0.05 mg/L) and low nutrient to BOD 5 ratios of wastewaters in the LS-ASB trial, the high % BOD 5 removal indicated recycling of nutrients from sludge [sourced from the FS-ASB]. Despite coagulation of pulp mill wastewater being performed using a very high alum dose (∼2000 mg/L) to remove colour and its precursors, colour formation remained high throughout the simulated ASB trials. Simulation of discontinuation of pulping indicated that colour would reduce rapidly to low levels in ASB wastewaters, but that TP and TN concentrations would persist for longer periods of time and decline slowly. Survey data of water qualities of the FS-ASB system obtained before, during and 2 years after discontinuation of pulping are presented., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

In this study, Moringa oleifera (M. oleifera) performance as an eco-friendly coagulant in the enhanced primary treatment of paper mill effluent was investigated. Its performance in terms of turbidity removal and COD abatement was examined. Local M. oleifera seed powder from ADRAR-city, South of Algeria, was used. Conventional jar tests were conducted for enhancing the primary treatment of paper mill effluent from paper factory. For this reason, comparative coagulation tests were performed using aluminum sulfate (alum). Indeed, in terms of turbidity abatement, 96.02% and 97.1% were obtained for Moringa and alum, respectively. However, in the case of COD abatement, the abatement rate of M. oleifera seeds was slightly higher than that of alum, 97.28% and 92.67%, respectively. Because M. oleifera is a natural resource that is locally available, an eco-friendly coagulant, non-toxic, and biodegradable and does not affect the pH of water; thus, its use allows to avoid numerous disadvantages of conventional coagulants like alum., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Microplastics (MPs) have been found in many packaged food products such as salt, tea bags, milk, and fish. In a previous study by this group, MPs were found to leach into hot water from the plastic lining of disposable paper cups. No studies were found in the literature quantifying health risks or lifetime intake of MPs. At present, it is not possible to quantify health risks due to MPs because dose-response and toxicity assessments are not available. Therefore, the objective of the current study was to assess the intake of MPs and associated contaminants like fluoride that are released into these hot beverages. MPs in the previous study were quantified in terms of particle counts only and a simple method was adopted in the present study to convert the microplastics count into its respective mass. Chronic daily intake (CDI) and lifetime intake (LTI) of MPs through the ingestion pathway were calculated. CDI and Hazard Quotient (HQ) due to fluoride ingestion were also estimated following USEPA guidelines. Monte Carlo (MC) simulations were used to account for the variability in input variables such as concentration of MPs, body weight, averaging time, exposure duration, exposure frequency and ingestion rate to evaluate the impact on CDI and LTI values. The CDI was used to estimate the LTI of MPs and HQ for fluoride ingestion. MC simulations with 100,000 iterations resulted in an average CDI of 0.03 ± 0.025 mg of microplastic per kg of body weight per day and 7.04 ± 8.8 μg fluoride per kg body weight per day. This study takes us one step closer to estimating the human health risk due to the ingestion of microplastics and other contaminants through food items., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Sudha Goel reports financial support, administrative support, and equipment, drugs, or supplies were provided by Indian Institute of Technology Kharagpur. Sudha Goel reports a relationship with Indian Institute of Technology Kharagpur that includes: employment. Sudha Goel has patent none pending to none. None., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Anaerobic digestion of floated paperboard sludge (PS) cake suffers from volatile fatty acids (VFAs) accumulation, nutrient unbalanced condition, and generation of digestate with a risk of secondary pollution. To overcome these drawbacks, sewage sludge (SS) was added to PS cake for biogas recovery improvement under a co-digestion process followed by the thermal treatment of solid fraction of digestate for biochar production. Batch experimental assays were conducted at different SS:PS mixing ratios of 70:30, 50:50, 30:70, and 20:80 (w/w), and their anaerobic co-digestion performances were compared to the mono-digestion systems at 35 ± 0.2 °C for 45 days. The highest methane yield (MY) of 241.68 ± 14.81 mL/g COD removed was obtained at the optimum SS:PS ratio of 50:50 (w/w). This experimental condition was accompanied by protein, carbohydrate, and VFA conversion efficiencies of 47.3 ± 3.2%, 46.8 ± 3.2%, and 56.3 ± 3.8%, respectively. The synergistic effect of SS and PS cake encouraged the dominance of Bacteroidota (23.19%), Proteobacteria (49.65%), Patescibacteria (8.12%), and Acidovorax (12.60%) responsible for hydrolyzing the complex organic compounds and converting the VFAs into biomethane. Further, the solid fraction of digestate was subjected to thermal treatment at a temperature of 500 °C for 2.0 h, under an oxygen-limited condition. The obtained biochar had a yield of 0.48 g/g dry digestate, and its oxygen-to-carbon (O/C), carbon-to-nitrogen (C/N), and carbon-to-phosphorous (C/P) ratios were 0.55, 10.23, and 16.42, respectively. A combined anaerobic co-digestion/pyrolysis system (capacity 50 m 3 /d) was designed based on the COD mass balance experimental data and biogenic CO 2 market price of 22 USD/ton. This project could earn profits from biogas (12,565 USD/yr), biochar (6641 USD/yr), carbon credit (8014 USD/yr), and COD shadow price (6932 USD/yr). The proposed project could maintain a payback period of 6.60 yr. However, further studies are required to determine the associated life cycle cost model that is useful to validate the batch experiment assumptions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The graphene quantum dots (GQDs) was synthesized using potato starch and water by hydrothermal method and further used for reduction of tetracholoroauric acid to form graphene quantum dots-gold (GQDs@AuNPs) nanocomposite. The GQDs/GQDs@AuNPs were analyzed using FTIR, UV-Vis, Flourometry and HR-TEM. The synthesized GQDs@AuNPs were further used for fabrication of cost-effective screen-printed paper electrode (SPPE) based DNA sensor for the detection of O. tsutsugamushi using htrA gene specific 5'NH2 linked DNA probe. Modification of SPPE using GQDs@AuNPs nanocomposite and ssDNA probe was monitored using EIS, FTIR, FE-SEM and AFM. The sensor detection limit (LOD) was assessed as 0.002 ng/μl from the standard calibration curve with the correlation coefficient, R 2  = 0.993. The sensitivity of the DNA sensor was calculated as 7700 μA/cm 2 /ng for ssGDNA of O. tsutsugamushi using cyclic voltammetry. The sensor validation was done using scrub typhus patient's blood DNA samples. The sensor showed good storage stability at 4 °C for six months with just a loss of 12% of the initial current values. The SPPE/DNA sensor developed is very specific, sensitive, stable and detects O. tsutsugamushi in less time., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Organic toxins are persistent chemicals of global concern capable of accumulating in environment and food. Surface enhanced Raman spectroscopy (SERS) is a promising technique that facilitates onsite detection of organic toxins. However, the fabrication of a SERS substrate is complicated and difficult to provide flexibility, fastness and cost-effectiveness. This study aims to develop a paper-based SERS method using grape skin-gold nanoparticles/graphene oxide (GE-AuNPs/GO) as SERS substrate and evaluate its efficiency with rhodamine 6G (Rh6G) as a model organic toxin and a real water and food contaminant. GE-AuNPs synthesized by green method using grape skin waste extract and GE-AuNPs/GO showed a surface plasmon resonance at 536 and 539 nm, particle size 18.6 and 19.5 nm, and zeta potential -44.6 and -59.7 mV, respectively. Paper-based SERS substrates were prepared by coating a hydrophobic thin-film of 30% polydimethylsiloxane solution in hexane on Whatman no. 1 filter paper, followed by drop-casting GE-AuNPs or GE-AuNPs/GO and drying. The SERS signals of Rh6G showed an enhancement factor of 5.8 × 10 4 for GE-AuNPs and 1.92 × 10 9 for GE-AuNPs/GO, implying that a combination of electromagnetic surface plasmon, charge transfer and molecular resonances may be responsible for a higher enhancement of signal by the latter. A low detection limit of 7.33 × 10 -11  M in the linear range of 10 -11 -10 -5  M was obtained for GE-AuNPs/GO, while the relative standard deviation of repeatability and reproducibility was 9.6 and 12.6%, respectively. Paper-based GE-AuNPs/GO SERS substrate was highly stable as <20% loss in efficiency was shown over a 60-day storage period. Application to real samples showed a high recovery of Rh6G from tap water (93.9-100.8%) as well as food samples such as red chilli powder (91.0-95.4%), red glutinous rice ball (96.6-98.3%) and tomato ketchup (98.9-102.3%) after QuEChERS extraction. Collectively, the developed paper-based GE-AuNPs/GO can be a potential substrate for sensitive onsite detection of rhodamine 6G by SERS method., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Thermal paper contains potentially toxic compounds such as bisphenol A (BPA), which is used as a color developer. BPA has been reported in thermal paper in concentrations up to 42,600 μg g -1 . The exposure to BPA via dermal transfer has been recently discussed as a significant contribution to the overall human exposure and the estimated daily intake (EDI) has been reported up to 218 μg d -1 . BPA has been also detected in recycled paper with concentrations up to 46 μg g -1 . Due to the fact that BPA is a known endocrine disruptor and migrates from materials, regulatory restrictions have been established to prevent risks for the human health. As a consequence, structural analogues, such as bisphenol S (BPS) have been introduced into the market. Little is known about the presence and toxicity of these emerging replacements, and concern has risen about them. The present review gives an overview of the occurrence and levels of BPA and replacements in thermal paper. BPA is still the most common color developer found in thermal paper, followed by BPS. The analytical methods used for quantification of BPA and BPA replacements in paper products are also reviewed. BPA is transferred from thermal paper products to the finger pads upon handling it. Paper-skin transfer followed by penetration of BPA depends on conditions (e.g. greasiness of fingers and use of hand cream). It is, however, still debated whether thermal paper as a source for human exposure contributes significantly to the overall internal BPA exposure., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

A lignin peroxidases-producing Serratia liquefaciens was used for bioremediation of pulp and paper (P&P) mill effluent. The treatment led to reduction of chemical oxygen demand (COD), colour, lignin and phenolic content by 84%, 72%, 61% and 95%, respectively. The effluent detoxification was studied by genotoxicity assays using Allium cepa L. (onion) root tip cells. Genotoxicity studies included measuring mitotic index (MI), chromosomal aberrations (CA) and nuclear abnormalities (NA) in root tip cells following treatment with 25, 50, 75 and 100% (v/v) of effluent. The root tip cells grown in untreated effluent showed a significant decrease in MI from 69% (control) to 32%, 27%, 22% and 11% at 25%, 50%, 75% and 100% effluent concentration, respectively. This indicated that the untreated effluent was highly cytotoxic in nature. Further, root tip cells, when treated with different concentrations of effluent showed various CA and NA including c-mitosis, stickiness, chromosome loss, chromosome break, anaphase bridge, multipolar anaphase, vagrant chromosomes, micronucleated and binucleated cells. The MI observed in root tip cells grown in bacterial treated effluents at similar concentrations (25, 50, 75 and 100% v/v) showed an increase of 33%, 36%, 42% and 66%. CA showed a substantial decrease and in some instances, complete absence of CA was also observed. The findings suggest that S. liquefaciens culture could be a potential bacterial culture for bioremediation of P&P mill effluent, as it is effective in substantial lowering of pollutants load as well as reduces the cytotoxic and genotoxic effects of effluent., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

This study firstly investigated the species, concentration variation, and emission factors of mercury emitted from the burning of incenses and joss papers in an Asian temple. Both indoor and outdoor speciated mercury (GEM, GOM, and PHg) were sampled by manual samplers, while ambient GEM at an indoor site was in-situ monitored by a continuous GEM monitor. Field measurement results showed that the total atmospheric mercury (TAM) concentrations in indoor and outdoor environments were in the range of 8.03-35.72 and 6.03-31.35 ng/m 3 , respectively. The indoor and outdoor ratios (I/O) of TAM in the daytime and at nighttime were in the range of 0.64-0.90 and 1.50-2.04, respectively. The concentrations of GEM, GOM, and PHg during the holiday periods were approximately 1-4 times higher than those during the non-holiday periods. GEM was the dominant mercury species in the indoor and outdoor environments and accounted for 63-81% of TAM, while the oxidized mercury accounted for 19-37% of TAM. Burning incenses and joss papers in a combustion chamber showed that the concentration of GEM from joss paper burning ranged from 4.07 to 11.62 μg/m 3 , or about 13.97 times higher than that of incense burning, while the concentration of PHg from incense burning ranged from 95.91 to 135.07 ng/m 3 , or about 3.29 times higher than that of joss paper burning. The emission factors of incense burning were 10.39 ng/g of GEM and 1.40 ng/g of PHg, while those of joss paper burning were 12.65 ng/g of GEM and 1.27 ng/g of PHg, respectively. This study revealed that speciated mercury emitted from worship activities had significant influence on the indoor and outdoor mercury concentrations in an Asian temple. Higher intensity of worship activities during holidays resulted in a higher concentration of speciated mercury in indoor and outdoor air, which might cause health threats to worshipers, staffs, and surrounding inhabitants through long-term exposure., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

In the present study, the concurrent fixed-bed dual technology (photocatalysis and photo-Fenton) was performed as a polishing step for the color removal of tertiary treated agro-based paper & pulp industry effluent. For this purpose, the cheap and visibly dynamic Fe-TiO 2 composite was prepared using industrial waste materials which also promoted the idea of the circular economy. The effectiveness of the prepared composite and the dual process was evaluated in terms of color removal efficiency and rate constant along with optimizing the process factors. Various kinetic models namely Log-linear, Weibull, and Biphasic with shoulder were used for the comparative study of three different processes i.e. photocatalysis, photo-Fenton, and dual process. Several parameters such as pH (4.5), % surface area covered (100%), and H 2 O 2 dose (525 mgL -1 ) were optimized which gave the best output using dual-process i.e. 91.6% of color reduction along with good R 2 values i.e. 0.874, 0.981 and, 0.998 for Log-linear, Weibull and, Biphasic with Shoulder model respectively. The proposed composite was durable enough to retain its dual catalytic ability with minor activity reduction of 5-10% even after 50 recycles. Thus, this innovative technology with the dual effect of photocatalysis and photo-Fenton can be a potential bet as a tertiary treatment option in the existing industrial wastewater treatment system for removing color from the final treated effluent., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The pulp and paper industry consumes enormous quality of freshwater, leading to wastewater. It must be treated to remove pollutants, particularly residual dyestuffs, before releasing them to water bodies to avoid adverse environmental effects. The traditional wastewater treatment methods used for the pulp and paper industry are less efficient in colour and chemical oxygen demand (COD) removal. The current study is aimed at developing a novel catalyst for the catalytic ozonation of pulp and paper wastewater with better colour and COD removal for sustainable resources of clean water. The proposed catalyst is impregnated by iron on natural zeolites. Various parameters such as catalyst dose, pH, ozone dose, initial COD concentration, and reaction time are studied and optimized. The performance was evaluated by comparing the results with the single ozonation process (SOP) and catalytic ozonation process (COP). The highest COD and colour reduction efficiencies have been achieved, i.e., 71%, and 88% at a natural pH of 6.8. The proposed process achieved higher COD and colour efficiencies than the single ozonation process and catalytic ozonation process using raw zeolites. The improvement in efficiencies are 23% and 29% for SOP and 17% and 19% for COP, respectively. Hence, the results proposed the sustainability and applicability of COP to treat paper and pulp sector effluent., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Facing the huge output of food waste (FW) and paper waste (PW), long-term semi-continuous experiments were carried out to investigate the effect of the substrate organic composition on mesophilic and thermophilic anaerobic co-digestions (Co-ADs) of their mixtures. The experimental results showed that the organic composition of the substrate affected the biogas and methane production and yield of the two Co-ADs of the FW and PW mixtures, and its effect on thermophilic Co-AD (Co-TAD) was lower than that on mesophilic Co-AD (Co-MAD). The two Co-ADs had similar biogas (2.158 ± 0.136 L/L/d and 2.183 ± 0.142 L/L/d) and methane production (1.245 ± 0.082 L/L/d and 1.279 ± 0.088 L/L/d), and organic matter degradation (81.79 ± 1.07% and 83.81 ± 1.09%) when the substrate organic composition was carbohydrates:proteins:lipids = 6.8:1.8:1 (low carbohydrate composition, FW:PW = 4:1). When the substrate organic composition was carbohydrates:proteins:lipids = 13.5:2:1 (high carbohydrate composition, FW:PW = 1:1), the thermophilic temperature was more favorable than the mesophilic temperature for the Co-AD of FW and PW mixtures. The characteristics (pH, total ammonia, total volatile fatty acids, and total alkalinity) of the Co-TAD digestate were more sensitive to changes in the organic composition of the substrate than those of the Co-MAD digestate. Increasing the carbohydrate content of the FW:PW mixture lowered the production of biogas and methane, and degradation of organic matter in both Co-ADs., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Bisphenol A (BPA) a synthetic, high production volume chemical identified as endocrine disruptor and toxic to reproduction is mainly used in the production of polycarbonate plastics, in epoxy resins, polyvinylchloride, thermal papers as color developer, and is present in a wide range of consumer goods such as food packaging materials, storage containers, and cash receipts. Due to its effects on health and legal restrictions, BPA is increasingly replaced by other bisphenols. In this study, BPA and 13 alternatives including BPS, Bisphenol F (BPF), Bisphenol B (BPB), Bisphenol C (BPC), Bisphenol Z (BPZ), Bisphenol M (BPM), Bisphenol P (BPP), Bisphenol AF (BPAF), Bisphenol FL (BPFL), Bisphenol C12 (BPC12), Tetramethylbisphenol A (tmBPA), 4,4-bisphenol (BP-4,4), and p,p-oxybisphenol were analyzed in thermal paper cash receipts (content) and migration studies were carried out in BPA-free labelled reusable plastic drinking bottles using a sensitive UHPLC-MS/MS method. The receipts contained almost only BPA and BPS, whereas BPS was found in all samples ranging at levels up to 38 μg/g. BPA was detected at low concentrations, only in one sample 11,000 μg/g were found, exceeding the EU limit of BPA in thermal paper of 0.02% per weight. In leaching solutions from the drinking bottles BPA, BPS and BPF were found at concentrations up to 0.047 μg/L BPA, 0.043 μg/L BPS, and <0.01 μg/L BPF. No other analogues were detected. However, these levels identified are far below the legal limits. In addition, a theoretical exposure assessment was conducted indicating that exposures were within the current regulatory guidelines., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Herein, using dialdehyde waste paper (DAWP) as a cross-linking agent to immobilize persimmon tannin (PT) was first used to remove the U(VI) and Cr(VI) via the "waste control by waste" concept. The microscopic and macroscopic surface properties of the as-prepared adsorbent was characterized by the advanced characterization techniques. Factors that affected the elimination process such as variable pH, coexistence ions and equilibrium time were investigated by batch techniques. The results showed that the maximal removal capacities of U(VI) and Cr(VI) on DAWP-PT were 242.3 mg/g (pH = 6.0) and 178.7 mg/g (pH = 2.0) at 298 K, which exhibited competitiveness with most of the reported solid materials. Meanwhile, adsorption data were fitted perfectly to the Langmuir and Pseudo-second-order equations, which indicated that the monolayer and homogenous chemisorption dominated the removal process. The SEM-EDX, DFT and XPS analysis conformed that adsorption of U(VI) was mainly via surface complexation, while the elimination of Cr(VI) was a redox reaction process, and about 65.33% of Cr(III) and 34.67% of Cr(VI) co-existed onto the surface of DAWP-PT. Thus, this study would provide a high-efficiency and low-cost adsorbent for radionuclide and heavy metal treatment., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Herein, bifunctional two-dimensional copper-aluminum modified filter paper composite (2D-Cu/Al-C) was successfully prepared by simple calcination and showed ultrahigh adsorption performance and degradation potential. The adsorption removal of TC on 2D-Cu/Al-C all exceeded 92.2% under solution conditions of 10-200 mg/L TC, 100 mg/L 2D-Cu/Al-C, pH 8 and 298 K. The pseudo-second-order kinetic and Langmuir models better fitted the kinetic and isotherm data via spontaneous and exothermic process, and the maximum capacity of the 2D-Cu/Al-C was 2391.78 mg/g. Additionally, 2D-Cu/Al-C showed desired specific adsorption for TC (TC: 98.7%, norfloxacin: 5.8%, sulfamethoxazole: 2.1%, and ciprofloxacin: 1.8%) and it could effectively adsorbed TC even in the binary system (various coexisting ions or natural organic matter). After TC adsorbed on adsorbent was mineralized into CO 2 and H 2 O by adding peroxydisulfate to generate high electrode potential radical in another limited systems, the 2D-Cu/Al-C still had ∼89.12% on TC removal (initial concentration of 50 mg/L) after five experimental cycles. Zeta potential, FT-IR and XPS results indicated that the multi-adsorption mechanism, including electrostatic interactions, complexation, and H-bonds, played a vital role in the fast and efficient adsorption process. Thus, the way of combining adsorption and regeneration via degradation are green, non-polluting strategy which are expected to be applied for water purification in future environmental remediation., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The study was conducted with an aim to remediate effluent from a pulp and paper mill, after treating it for 28 days with an aquatic fern, Salvinia cucullata. The effluent had high BOD, COD, TS, TSS, TDS, P, hardness and chloride, and several heavy metals (Cd, Cu, Cr, Ni, Pb, Mg, Mn, Fe and Zn) above national limits. However, the plant survived a wide range of effluent concentrations (25%, 50%, 75% and 100%, v/v), and flourished well, particularly at 25% (v/v), resisted membrane injury and generation of H2O2 and O2, showed better growth and induced all the major antioxidant enzymes. The plants also induced lipid peroxidation. Most of the elemental profiles were higher than the toxic levels stipulated for plants, indicating tolerance to metal. In fact, barring Fe, for Cr, Cu, Pb, Zn, Mg and P, at all the effluent doses, and for Cd, Ni and Mn, up to 75% (v/v) effluent, greater concentrations were observed in leaf than in root. This plant was more suited for nutrient removal, as it effectively reduced BOD, Zn, Fe, Ni, Mg, P and increased dissolve oxygen. Further, pH, hardness, chloride, TS and Mn was reduced optimally by 25-50% (v/v) treatments. SEM revealed prominent structural damages from 50 to 100% treatments. Presence of Pb as well as Fe in the EDX peaks were observed in the cortex rather than in the root vascular zone. This plant could be suggested to be an effective phytoremediator of multi-contaminant effluent with maximum benefit at low doses (25-50%, v/v)., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

A SERS substrate FP/Ag/ZIF-8 composed of filter paper (FP), silver nanoparticles (AgNPs) and zeolitic imidazolate framework (ZIF-8) film arranged in a layered structure was developed for sensitive detection of pesticide thiram in various samples. Roles of these components in analyte adsorption and Raman signal enhancement were studied using a pesticide intermediate 4-Aminothiophenol (4-ATP) as the probe. The substrate showed high adsorption and optimized SERS response with thick metal organic framework (MOF) coating (125 nm), which is different from previous reported plasmonic particle-MOF composite substrate, where thinnest MOF coating produced the strongest SERS signal. Detection limit for 4-ATP improved 1000-fold on FP/Ag/ZIF-8 (3 pM) compared with that on FP/Ag (3 nM). Importantly, the FP/Ag/ZIF-8 with porous and flexible property can efficiently capture pesticide thiram in different real samples using soaking, filtration or swabbing operation. The subsequent SERS detection of thiram showed advantages of low detection limit (soaking, LOD: 0.04 nM in lake water), fast detection (filtration, within 1 min in peach juice) and suitable for curve surface analysis (swabbing, LOD: 0.1 ng/cm 2 on apple peel), respectively. The substrate also displayed good reproducibility, high stability and size-selective response for thiram detection. Such a layered plasmonic particle/MOF hybrid may hold great promise for toxicant analysis in environment and food., (Copyright © 2021. Published by Elsevier Ltd.)

The sustainable application of an up-flow anaerobic baffled reactor (UABR) to treat real paper and cardboard industrial effluent (PCIE) containing bronopol (2-bromo-2-nitropropan-1, 3-diol) was investigated. At a hydraulic retention time (HRT) of 11.7 h and a bronopol concentration of 7.0 mg L -1 , the removal efficiencies of total chemical oxygen demand (COD total ), COD soluble , COD particulate , total suspended solids (TSS), volatile suspended solids (VSS), carbohydrates, and proteins were 55.3 ± 5.2%, 26.8 ± 2.3%, 94.4 ± 4.6%, 89.4 ± 2.6%, 84.5 ± 3.2%, 72.1 ± 1.8%, and 22.4 ± 1.8%, respectively. The conversion of complex organics (e.g., carbohydrates and proteins) into bio-methane (CH 4 ) was assisted via enzyme activities of, in U (100 mL) -1 , α-amylase (224-270), α-xylanase (171-188), carboxymethyl cellulase (CM-cellulase) (146-187), polygalacturonase (56-126), and protease (67,000-75300). The acidogenic condition was dominant at a short HRT of 2.9 h, where methane yield dropped by 32.5%. Under this condition, the growth of methanogenic bacteria could be inhibited by volatile fatty acids (VFA) accumulation. The analysis of Fourier-transform infrared (FTIR) spectra detected peaks relevant to methylene and nitro groups in the sludge samples, suggesting that entrapment/adsorption by the sludge bed could be a major mechanism for removing bronopol. The economic feasibility of UABR, as proposed to receive 100 m 3  d -1 of PCIE, showed a payback period (profits from environmental benefits, biogas recovery, and carbon credit) of 7.6 yr. The study outcomes showed a high connection to the environmental-, economic-, and social-related sustainable development goals (SDGs)., (Copyright © 2021. Published by Elsevier Ltd.)

Over the past three decades, groundwater remediation using permeable reactive barriers (PRBs) has proven to be effective. The majority of installed PRBs uses metallic iron (Fe(0)) as a reactive material. However, the success of implemented Fe(0) PRBs is yet to be rationalized as Fe(0) is a generator of iron oxides (contaminant scavengers) and secondary reducing agents (e.g. Fe(II), Fe 3 O 4 , H 2 , green rust), This communication demonstrates that Fe(0) is not an environmental reducing agent. Therefore, more science-based investigations are needed to optimize the operation of Fe(0) PRBs. In particular, Fe(0) PRBs and Fe(0)-based water filters should be regarded as particular cases of "metal corrosion in porous media". A key feature of such systems is that the extent of Fe 0 corrosion temporally depends on the residual porosity (capillarity). Thus, the functionality of any Fe 0 PRB should be monitored in a way that the time-dependent variation of the kinetic of iron corrosion is discussed., (Copyright © 2021. Published by Elsevier Ltd.)

The aim of the study was to use black liquor produced during the soda pulping process in a pulp and paper mill to increase methane production during pulp and paper industry sludge treatment and decrease the treatment cost. The effects of black liquor on sludge solubilization and methane production were assessed and the economic feasibility of the process was evaluated. Black liquor and NaOH were found to be equivalent in the thermochemical pretreatment process to solubilize sludge and disintegrate flocs. However, adding black liquor increased the background chemical oxygen demand and volatile fatty acid concentration and increased the amount of methane produced by approximately 7-30%. A start-up delay was emphasized by first-order kinetics model due to black liquor addition while methane production remained stable. Economic assessments of five scenarios were performed. It was found to be economically feasible to use black liquor to replace NaOH for the thermal pretreatment process. The surplus methane generated suggested that co-digestion of sludge and black liquor allows surplus bioenergy to be produced during the thermochemical pretreatment anaerobic digestion process., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Microplastics are among the ubiquitous contaminants in our environment. As emerging contaminants, microplastics are still facing with lots of challenges on the characterisation, including their capture, identification and visualisation, particularly from a complex background. For example, when we print documents using a laser printer, we are printing microplastics onto paper, because the plastics are the main ingredient of the toner powder mixture. Characterisation of these microplastic mixture meets an even more complicated challenge, because plastic's signals might be shielded by other toner powder ingredients such as the pigments, the dyes, the black carbon, and the paper fabrics as well. To solve this challenge, we employ various techniques, including SEM, TEM, XPS, FT-IR, TGA and Raman, to characterise the microplastics printed via the toner powders. Interestingly, we show that Raman can distinguish and visualise the distribution of the microplastics from the complex background of the mixture. We estimate the millions of toner powders, each of which is ~4-6 μm in size, are printed out per A4 sheet as microplastics. The findings send a strong warning that millions of microplastics might be generated from the printing activities in our daily lives., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

In this study, a facile and effective route to prepare hybrid photocatalysts (paper-TiO 2 , paper-TiO 2 -AgBr and paper-AgBr-TiO 2 ) has been reported. The preparation procedure consisted of the direct adsorption of the previously synthesized titania nanoparticles (TiO 2 sol) to generate the TiO 2 nanosphere and the immersion process in an aqueous suspension of AgBr to form the AgBr nanoclusters on paper fibers. The synthesis technology is economic, efficient, environmentally friendly and easy to implement even at industrial scale. A cellulose-based structure with well dispersed TiO 2 particles of around 1 μm and a pseudo-liquid coating of Ag + and AgBr species was obtained. All the prepared photocatalysts demonstrated effective photocatalytic performance in gaseous phase ethanol degradation with simulated sunlight illumination, through the direct mineralization to CO 2 and the parallel reaction via acetaldehyde degradation. A relevant improvement in the photocatalytic activity was noticed when TiO 2 was associated with AgBr nanocrystals, with a higher effect observed when AgBr was loaded onto the paper surface prior to TiO 2 . Ag-Ti interaction reduces the pair recombination rate and increases the available charge carriers generating reactive OH- radicals from both Ag-species and TiO 2 , and O 2 - radicals from Ag + -AgBr species, which would be involved in the ethanol degradation process., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In this study, carbon-based aerogels derived from waste paper (CWP) were explored as an efficent adsorbent to remove organic pollutants including phenol (Ph) and 2-chlorophenol (2CP) from wastewater. CWP exhibited a highly porous structure and large specific surface area of 892 m 2  g -1 , which facilitated the adsorption of Ph and 2CP in wastewater. The adsorption behavior of Ph and 2CP on CWP could be well described by the pseudo-second-order kinetics and Langmuir isotherm models. Based on the Langmuir isotherm, the maximum adsorption capacities of CWP for Ph and 2CP were 238 and 278 mg g -1 , respectively, and these values were much higher than those of other adsorbents. The removal of the organic pollutants mainly occurred through electrostatic attraction, pore-filling, hydrogen bonding, and π-π interactions. The CWP can be directly applied for the removal of Ph and 2CP at low concentration (<200 mg L -1 ) in the wastewater, while they can be used with additional pre-treatment for wastewater containing high concentration of organic pollutants. The adsorptive recovery of organic compounds and potential reuse of treated wastewater were also discussed. This work provides an efficient approach to produce effective adsorbent for the removal and recovery of chemicals from wastewater., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Bisphenol A (BPA) was commonly used as color developer for thermal paper such as cash register receipts, labels or tickets. Therefore, thermal paper was considered by the European Food Safety Authority (EFSA) as the main source of human exposure to BPA beside epoxy based food contact materials. In this study, a German market analysis on the use of BPA and alternative color developers in thermal paper receipts is provided for the years 2015, 2016 and 2017.114 (2015), 98 (2016) and 99 (2017) samples were randomly collected and analyzed by HPLC-DAD. In summary, BPA was still the most frequently found color developer (48.2% in 2015, 46.9% in 2016 and 52.5% in 2017). The most commonly used alternative was the phenol-free substance Pergafast ® 201 (34.2%, 33.7%, 40.4%). The bisphenol analogs bisphenol S (BPS; 11.4%, 9.2%, 6.1%) and D8 (6.1%, 7.1%, 1.0%) were less common. Another phenol-free substituent, a urea urethane compound (UU), was also detected (3.1% in 2016). Concentrations of color developers in thermal paper ranged from 1.4 to 32.4 mg/g (median values between 2.5 and 15.9 mg/g). Concentrations of BPA were found to be highest followed by BPS, UU, Pergafast ® 201 and D8. In addition, two pharmacologically active substances, dapsone (6.0 mg/g) and tolbutamide (5.5 mg/g), were detected in a non-marketed thermal paper, that was supposed to use ascorbic acid as initial color developer. Different release experiments of the detected color developers were performed. Sensitizers 1,2-diphenoxy-ethane, 1-phenylmethoxy-naphthalene and diphenylsulfone, used frequently in the thermal paper processes, were quantified., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Enzyme-aided Cl 2 bleaching is widely considered as promising replacements for conventional Cl 2 bleaching in wood pulp and paper mills. However, the effects of using enzyme-aided bleaching on the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the non-wood pulp and paper mills are unclear. A field study was performed to investigate PCDD/F formation when enzyme-aided Cl 2 bleaching was used to replace conventional Cl 2 bleaching in non-wood pulp and paper mills. Unexpectedly, the PCDD/F toxic equivalents (TEQs) in solid samples were higher when using enzyme-aided bleaching (0.49-5.4 pg TEQ/g) than that using conventional Cl 2 bleaching (0.15-2.44 pg TEQ/g). Large amounts of octachlorodibenzo-p-dioxin were formed during the enzyme-aided bleaching process. This could have been because enzyme strongly promoted the release of organic molecules bound to lignin and thus accelerated the formation of octachlorodibenzo-p-dioxin through organic molecular precursors. Although enzyme-aided Cl 2 bleaching was previously considered to be efficient for reducing PCDD/F releases and to be the best available technologies and best environmental practices for wood pulp and paper mills, the results obtained in this study suggested the necessity and urgency to evaluate the suitability of enzyme-aided Cl 2 bleaching for non-wood pulp and paper mills that intensively practiced in developing countries., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Nanowires synthesized from metal oxides exhibit better conductivity than nanoparticles due to their greater aspect ratio which means that they can transmit electrons over longer distances; in addition, they are also more widely available than pili because their synthesis is not affected by the bacteria themselves. However, there is still little research on the application of metal oxides nanowires to enhance power generation of microbial fuel cells (MFC). In this study, a simple hydrothermal synthesis method was adopted to synthesize α-FeOOH nanowires on carbon paper (α-FeOOH-NWs), which serve as an anode to explore the mechanism of power generation enhancement of MFC. Characterization results reveal α-FeOOH-NWs on carbon paper are approximately 30-50 nm in diameter, with goethite structure. Electrochemical test results indicate that α-FeOOH nanowires could enhance the electrochemical activity of carbon paper and reduce the electron transfer resistance (R ct ). Furthermore, α-FeOOH-NWs made the power density of MFC 3.2 times of the control device. SEM result demonstrates that nanowires are beneficial to the formation of biofilms and increase biomass on the electrode surface. Our results demonstrate that nanowires not only improve the electrochemical activity and conductivity of carbon paper but also facilitate the formation of biofilms and increase the biomass of the anode surface. These two mechanisms work together to boost extracellular electron transfer and power generation efficiency of MFC with α-FeOOH-NWs. Our study provides further evidence for the electrical conductivity of metal nanowires, promoting their potential applications in electricity generation such as MFC or other energy development fields., Competing Interests: Declaration of competing interest The authors declare no competing financial interests related to the publication of this study., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

By exploiting the hydrophilicity of cellulose filter paper (FP) and the excellent chelating property of chitosan (CH) for Mn 2+ , we have designed an efficient and retrievable dip catalyst MnO 2 /CH-FP for Fenton-like degradation of methylene blue (MB) over a wide pH range from 2.8 to 11.2. The MnO 2 nanoparticles were uniformly immobilized in the CH-FP matrix by in-situ redox precipitation method where Mn(NO 3 ) 2 was treated with KMnO 4 at mild conditions. A series of MnO 2 /CH-FP hybrids with different MnO 2 loading were fabricated via varying concentration of Mn(NO 3 ) 2 solution, and their structure-function relationships were discussed based on detailed characterization. The optimal catalyst 1.0MnO 2 /CH-FP could cooperate with multiple low-concentration dosages of H 2 O 2 to efficiently degrade 95.6% MB in 90 min (50 mg L -1 MB, 1 g L -1 catalyst, 30 mg L -1 H 2 O 2 , pH 7). It is also shown that 1.0MnO 2 /CH-FP could still keep 83.3% degradation efficiency of MB after six cycles. Moreover, the activity of this composite greatly surpassed that of bare MnO 2 for nearly 50%, owing to its larger surface area and more accessible active sites. This method for preparing MnO 2 /CH-FP could effectively avoid the agglomeration of MnO 2 nanoparticles and make the reaction turn on/off almost instantaneously by mere insertion/removal., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The current technologies to treat hypersaline produced water (PW), such as thermal evaporation, are usually energy-intensive and cost-prohibitive. This study developed a low-cost, robust, solar-driven carbon black and airlaid paper-based evaporator (CAPER) for desalination of PW in the Permian Basin, United States. The study aims to better understand the removal of aromatic organic compounds and heavy metals during solar distillation, water output, and heat transfer. Outdoor experiments using CAPER assisted with polystyrene foam in a single slope, single basin solar still achieved an enhanced average evaporation rate of 2.23 L per m 2 per day, 165% higher than that of a conventional solar still. Analysis of heat transfer models demonstrated that CAPER solar evaporation achieved an evaporative heat transfer coefficient of ∼28.9 W m -2 ·K -1 , 27.9% higher than without CAPER. The maximum fractional energy of evaporation and convection heat transfer inside the solar still with and without CAPER was ∼81.4% and ∼78.2%, respectively. For the PW with a total dissolved solids concentration of 134 g L -1 , solar distillation removed 99.97% salts and over 98% heavy metals. The high removal efficiency of 99.99% was achieved for Ca, Na, Mg, Mn, Ni, Se, Sr, and V. Organic characterization revealed that solar distillation removed over 83% aromatic compounds. Solar desalination using CAPER provides a low-cost and high-performance process to treat PW with high salinity and complex water chemistry for potential fit-for-purpose beneficial uses., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Perfluoroalkyl acids (PFAAs) are widely used as multi-purpose surfactants or water/oil repellents. In order to understand the contamination level and compositional profiles of PFAAs in aqueous environment in textile, leather, and paper making industrial areas, surface waters and tap waters were collected along the watershed of the Qiantang River where China's largest textile, leather, and paper making industrial bases are located. For comparison, surface water and tapwater samples were also collected in Hangzhou and its adjacent areas. 17 PFAAs were analyzed by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry. The results show that the total concentrations of PFAAs (ΣPFAAs) in the Qiantang River waters ranged from 106.1 to 322.9 ng/L, averaging 164.2 ng/L. The contamination levels have been found to be extremely high, comparable to the levels of the most serious PFAA contamination in surface waters of China. The PFAA composition profiles were characterized by the dominant PFOA (average 58.1% of the total PFAAs), and PFHxA (average 18.8%). The ΣPFAAs in tap water ranged from 9.5 to 174.8 ng/L, showing PFAA compositional pattern similar to the surface waters. Good correlations between PFAA composition profiles in tap waters and the surface waters were observed., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Chlorine bleaching technology (C process, CEH process, H process and theirs combination), which was identified as a primary formation source of PCDD/Fs, is still widely used by the vast majority of Chinese non-wood pulp and paper mills (non-wood PMs). The purpose of this study was to provide information and data support for further eliminating dioxin for non-wood PMs in China, and especially to evaluate the PCDD/Fs release reduction for those mills converting their pulp bleaching processes from CEH to ECF. The PCDD/Fs concentrations of the bleached pulp and bleaching wastewater with ECF bleaching were in the ranges of 0.13-0.8 ng TEQ kg -1 , and 0.15-1.9 pg TEQ L -1 , respectively, which were far lower than those with CEH process, indicating that the ECF process is an effective alternative bleaching technology to replace CEH in Chinese non-wood PMs to reduce dioxin release. The release factor via flue gas of the alkali recovery boiler in Chinese non-wood PMs was first reported to be 0.092 μg TEQ Ad t -1 in this study. On the assumption that pulp bleaching processes of all Chinese non-wood PMs were converted from CEH to ECF, the annual release of PCDD/Fs via the bleaching wastewater and bleached pulp would be reduced by 79.1%, with a total of 1.60 g TEQ., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Tricaine methanesulfonate (MS-222) has been widely used in intensive aquaculture systems to control stress during handling and confinement operations. This compound is dissolved in the water tanks and, once it is present in the Recirculating Aquaculture Systems (RASs), MS-222 can reach the environment by the discharge of contaminated effluents. The present work proposes the implementation of the adsorption process in the RASs, using pyrolysed biological paper mill sludge as adsorbent, to remove MS-222 from aquaculture wastewater. Adsorption experiments were performed under extreme operating conditions, simulating those corresponding to different farmed fish species: temperature (from 8 to 30 °C), salinity (from 0.8 to 35‰) and different contents of organic and inorganic matter in the aquaculture wastewater. Furthermore, the MS-222 adsorption from a real aquaculture effluent was compared with that from ultrapure water. Under the studied conditions, the performance of the produced adsorbent remained mostly the same, removing satisfactorily MS-222 from water. Therefore, it may be concluded that the produced adsorbent can be employed in intensive aquaculture wastewater treatment with the same performance independently of the farmed fish species., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Parahydroxybenzoates (parabens) are considered as emerging environmental contaminants because of their extensive usage in our daily life products, causing parabens contamination into environmental water systems and lead to toxic effects on environmental health. This study describes a greener extraction method using a new cationic polymer poly (ethyleneimine) functionalized acid-treated carbon nanofibers (PEI-CNFs) coated cellulose paper (CP) as solid-phase extraction (SPE) sorbent material for the extraction of parabens from environmental water samples. The fabrication of PEI-CNFs modified CP was confirmed using field-emission scanning electron microscope, transmission electron microscopy, and fourier-transformer infrared spectroscopy techniques. Various factors affecting the adsorption and desorption of parabens on PEI-CNFs@CP and its extraction efficiencies were studied using HPLC-UV analysis. Under the optimal experimental conditions, maximum extraction efficiencies were achieved for four target parabens, and PEI-CNFs@CP/HPLC-UV method exhibited excellent linearities ranged from 0.5-50 ng mL -1 with regression coefficient values were between 0.9952-0.9970. The presented method showed good sensitivity with quantification limits between 0.5-0.75 ng mL -1 and detection limits between 0.1-0.25 ng mL -1 . The developed technique was applied for the real sample analysis (river, lake, domestic sewage water, and drinking tap water). The spiked recovery revealed good recoveries between 86.8-116.0% with RSD less than 8.8% for all the water samples. These results proved that it a simple, fast, efficient, low-cost, and eco-friendly method for the extraction and determination of parabens in environmental water samples and can be applied as a routine analytical tool in environmental monitoring and quality control laboratories., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Three of the primary bottlenecks, which should be consider for practical, point-of-need use of microbial fuel cell (MFC) analytical devices were surpassed in this work: i) the use of a diffusive barrier, hence, an electrogenic biofilm; ii) longer enrichment/stabilization times to produce a biofilm, made in a laboratory environment, over the electrode; and iii) difficulty comparing results obtained from MFCs based on electrogenic biofilms with standardized bioassays, a setback to be adopted as a new method. Here we show an easy way to determine water toxicity employing planktonic bacteria as biorecognition agents. The paper-based MFC contain an electron carrier (or mediator) to facilitate charge transfer from bacteria to the anode. In this way, there is no need to use biofilms. As far as we know this is the first paper-based MFC containing P. putida KT2440, a well characterized non-pathogenic bacteria previously used in standardized water toxicity bioassays. Results were obtained in 80 min and an effective concentration 50 of 9.02 mg L -1 , calculated for Zn 2+ (a reference toxic agent), was successfully compared with previously published and ISO standardized bioassays, showing a promising future for this technology. The practical design and cost (less than one U.S. dollar) of the paper-based MFC toxicity test presented will open new market possibilities for rapid and easy-to-use MFC analytical devices., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)