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Treating hazardous landfill leachate poses significant environmental challenges due to its complex nature. In this study, we propose a novel approach for enhancing the anaerobic digestion of landfill leachate using silver nanoparticles (Ag NPs) conjugated with eco-friendly green silica nanoparticles (Si NPs). The synthesized Si NPs and Ag@Si NPs were characterized using various analytical techniques, including transmission electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy. The anaerobic digestion performance of Si NPs and Ag@Si NPs was tested by treating landfill leachate samples with 50 mg/L of each NP. The results demonstrated an enhancement in the biogas production rate compared to the control phase without the nanocomposite, as the biogas production increased by 14% and 37% using Si NPs and Ag@Si NPs. Ag@Si NPs effectively promoted the degradation of organic pollutants in the leachate, regarding chemical oxygen demand (COD) and volatile solids (VS) by 58% and 65%. Furthermore, microbial analysis revealed that Ag@Si NPs enhanced the activity of microbial species responsible for the methanogenic process. Overall, incorporating AgNPs conjugated with eco-friendly green Si NPs represents a sustainable and efficient approach for enhancing the anaerobic digestion of landfill leachate., 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 demand for paper and paper-based packaging has seen a massive increase in past years, resulting in accelerated deforestation to meet the rising demand, negatively impacting the environment, and there is a need to look towards different non-woody raw materials. Kraft pulping (KP) is widely used in paper making, for which the chemical dose, temperature, time, and energy required must be optimized, for which many insignificant experimental trials are performed. An effort is made to solve this problem by developing the regression equations with the help of Excel using One Factor at a Time Analysis (OFAT), followed by carrying out design of experiments (DoE) using orthogonal approach and regression analysis in Minitab software. Life cycle Assessment (LCA) using the Open-LCA software estimates the effect of chemicals and energy required during pulping on human health, ecosystem quality, and resource depletion. Using regression analysis, the equations for predicting kappa number, yield (%), total energy consumed, and mechanical properties of the paper sheet showed a good fit with an R 2 value in the range of 0.90-0.99. Apart from that, the mechanical properties, namely tensile index (41.43 Nm/g), tear index (6.96 mN m 2 /g), bending stiffness (0.5 mN m), and burst index (3.92 kPa m 2 /g) of the unbeaten sheet, were determined experimentally at optimized conditions. Based on the Open-LCA result, the optimized pulping conditions had less impact on human health, ecosystem quality, and resource depletion. Industries can use the model to predict the values of kappa number, yield, mechanical properties, and energy consumption without performing optimization experiments that may impact the industry's economy to a greater extent., 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.)

Free nitrous acid (FNA) is a critical metric for stabilization of ANAMMOX but can not be directly and immediately measured by sensors or chemical measurement method, which hinders the effective management and operation for ANAMMOX. This study focuses on FNA prediction using hybrid model based on temporal convolutional network (TCN) combined with attention mechanism (AM) optimized by multiobjective tree-structured parzen estimator (MOTPE), called MOTPE-TCNA. A case study in an ANAMMOX reactor is carried out. Results show that nitrogen removal rate (NRR) is highly correlated with FNA concentration, indicating that it can forecast the operational status by predicting FNA. Then, MOTPE successfully optimizes the hyperparameters of TCN, helping TCN achieve a high prediction accuracy, and AM furtherly improves model accuracy. MOTPE-TCNA obtains the highest prediction accuracy, whose R 2 value gets 0.992, increasing 1.71-11.80% compared to other models. As a deep neural network model, MOTPE-TCNA has more advantages than traditional machine learning methods in FNA prediction, which is beneficial to maintain the stable operation and easy control for ANAMMOX 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 © 2023 Elsevier Ltd. All rights reserved.)

Releases of hydrogen sulphide (H 2 S) and sulphur ions (S 2- ) through sulphate reduction in black-odorous waterbody is a great environmental health concern. Aquatic planting for blackening and odour controls has received great attention in research and practice. Nitrate concentration in black-odorous waterbody can vary significantly but little is known about the responses of aquatic plants on H 2 S and S 2- releases under different nitrate levels. This controlled laboratory study explored the changes of H 2 S and S 2- releases in simulated black-odorous waterbody planted with Vallisneria natans and artificial plants (control). V. natans growth was stimulated by additional nitrate (6.6 mg/L NO 3 - -N), resulting in an increase of dissolved oxygen (DO) and pH in overlying water and an 11.0% decrease in removal efficiency of chemical oxygen demand (COD). At relatively low nitrate level (i.e., 2.0 mg/L NO 3 - -N in the absence of additional nitrate), V. natans after the 48th day inhibited H 2 S and S 2- releases by 81.5% and 66.8%, respectively, and their inhibition efficiencies were improved to 95.7% and 98.8% by the presence of additional nitrate. Additional nitrate reduced the relative abundance of sulphate-reducing bacteria (SRB) in the sediments while increased the relative abundance of sulphur-oxidizing bacteria (SOB) and nitrate-reducing sulphur-oxidizing bacteria (NR-SOB) in the leaf biofilms of V. natans and artificial plants. Genus compositions in leaf biofilms showed host specificity. Pearson correlation analysis showed that DO, pH, and nitrate concentration had a positive correlation with the relative abundance of SOB (Aeromonas) and NR-SOB (Hydrogenophaga), while were negatively correlated with the relative abundance of SRB (MSBL7). These results indicated that V. natans under additional nitrate altered microbial community to be unfavourable for H 2 S and S 2- releases. This study clarified the inhibition of H 2 S and S 2- releases by aquatic planting under additional nitrate and provided theoretical basis for improving black-odorous waterbody restoration technology., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

It is expected that low-energy and scientific zero discharge of chemical-mechanical pulping wastewater will be achieved by applying the mechanical vapor recompression (MVR) technology. In this paper, the equal-standard pollution load model was introduced into pulp and paper field to parse the pollution sources for the first time. The results from the source apportionment indicated that the screw press and concentrating were the major pollution unit operations, and their cumulative load ratio reached 92.92%. The further survey demonstrated that the dominating pollution factors in the traditional chemical-mechanical pulping process were Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD 5 ), and Suspended Solids (SS), whose cumulative load ratio was 92.69%. The environmental analysis demonstrated the implementation of MVR technology significantly decreased the pollution load and reduce the pressure of subsequent wastewater treatment. In addition, a further economic performance indicated that the utilization of MVR technology possessed a smaller operating cost of 2.899 $/m 3 . The result of the given model provides a scientific gist and instruction for the future treatment of water pollutants in the chemical-mechanical pulping process. The MVR technology is conducive for wastewater treatment to minimize environmental effects and costs., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Generally, the mechanical strength and stiffness of old corrugated cardboard (OCC) waste paper are decreased after multiple recycling procedures. Surface sizing starch, which is extensively used in the surface sizing of paper making, accumulates after dissolving from the fibers and is transformed into pollutant during the OCC re-pulping process. To overcome the pollution and reutilization problem of the waste starch during the recycling process of OCC paper, waste starch was ionized using hydrogen peroxide (H 2 O 2 ) to improve the mechanical properties of OCC paper during the reutilization. The results showed that the carboxyl group of waste starch increased with an increasing degree of ionization, resulting in enhanced copper ion adsorption capacity. Furthermore, the retention rate of the modified starch in the wet-end increased from 18.0% to 48.2%. The OCC paper presented the highest burst index and tensile strength of 8.94 kPa m 2 /g and 112.5 N m/g, respectively, when MS-2 was added. This work has great significance for implementation of the cleaning production of OCC waste papers and the reutilization of the waste starch., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Lignocellulosic hydrogels are valuable bio-products that have been considered widely in recent investigations. Also, application of low value recycled fibers for high value added products can be of much interest. In this respect, current research has focused on producing hydrogel from recycled old corrugated container (OCC) resources, using 1-butyl-3-methyl-imidazolium chloride ionic liquid (IL) as a green solvent. The results indicated that the IL successfully dissolved OCC fibers, allowing the production of lignocellulosic hydrogel. Considering total water absorption amount as a main criterion for evaluation of hydrogels, the fabricated hydrogel showed promising results (up to 4700% water absorption). X-ray diffraction analysis confirmed obvious reduction in cellulose material crystallinity and crystallite size as a result of the process. Field emission scanning electron microscopy also demonstrated the microstructure of the hydrogel, pore size and shape in the hydrogel, which well supported the laboratory research results. Furthermore, the effect of processing parameters showed that specimens washed with distilled water as the anti-solvent resulted in the highest water absorption. Infrared spectroscopy can be used to suggest the presence of more lignin content in the hydrogel washed with ethanol. Moreover, the best water re-absorption results were observed for the hydrogel washed with distilled water., 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.)

Papermaking is a capital-intensive industry that requires a high consumption of plant fibers, energy, and water. Previous sustainability assessments of papermaking industry primarily focused on separate evaluations for multiple criteria without the integration for criteria and could not compare the overall priority of the production alternatives. The life cycle sustainability for the most representative boxboard production is analyzed as a case study in this work. Life cycle water consumption, energy consumption, greenhouse gas emissions, and internal costs are selected as the assessment criteria. The two multi-criteria decision-making methods are applied to integrate the above criteria to obtain the sustainability sequence under different production pathways. When the papermaking enterprises are regarded as decision-makers, the alternative using waste paper as raw material to manufacture boxboard is the most sustainable, following by mixed fiber. The sustainability sequence of the alternatives using wood and straw as raw materials is controversial due to the different calculation models. Changing the proportion of raw materials and the criteria weights might adjust sustainability sequence of the alternatives., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The pulp and paper industry is highly dependent on forest and water resources. It has more concerns on fair utilization of these resources and their conservation for its further expansion. Present study emphasizes on the use of rice straw (agro waste) in papermaking to protect wood based resources. It further deals with ozone bleaching (Z) prior to elemental chlorine free bleaching that proved to be significant in terms of reducing the effluent load specially the reduction in toxic, recalcitrant and carcinogenic compounds. Z based sequences resulted in pulp brightness of ∼85% that was 3.6% higher than the elemental chlorine free bleaching. Bleached pulps of Z based sequences were found to be having better strength properties than elemental chlorine based sequence and thus may be adopted as improved bleaching technology. The analysis of handsheets prepared after pulp bleaching was performed using X-Ray diffraction, ATR-FTIR and SEM. Incorporating ozone stage resulted in marked reduction of 58% and 63% in total solids in bleaching wastewater. Reduction of more than 80% in BOD, COD and adsorbable organic halides was achieved in Z based bleaching in comparison to chlorine bleaching. The amount of chlorophenols, guaiacols, catechols, vanillins and syringols became negligible (approx. 90% reduction) in effluents of Z based bleaching sequences. The chlorine dioxide followed by peroxide bleaching after Z stage was found to be the most promising to reduce the effluent load., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

This study was done with the aim of lignosulfonate and ethanol production from different spent liquors of bagasse pulping process. For this purpose, alkali lignin from bagasse alkali liquor was separated and was sulfomethylated to produce soda lignosulfonate (SLig). Furthermore, raw bagasse was directly treated with sodium sulfite in acidic and neutral conditions to produce BLig and NLig bagasse lignosulfonate, respectively. In addition, the pentoses and hexoses impurities in lignosulfonates were fermented to ethanol using Candida guilliermondii. Results showed that the molecular weight of NLig lignosulfonate was considerably high comparing to the SLig and BLig lignosulfonates. A high level of thermal resistance was found in case of SLig regarding to the other samples at 500 °C. Fermentation of the spent liquors with Candida guilliermondii led to a maximum ethanol yield of 7.0, 1.0 and 5.1 g L -1 in NLig, SLig and BLig, respectively., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The importance of water pollutants on human health has been the subject of intense study and constitutes perhaps the most significant grand challenge for the future of human society. Water remediation faces many challenges in effectively combating pollution, especially for low income populations where poor water sanitation and little to no access to technically competent and cost effective remediation are nearly insurmountable issues. In an effort to provide low-cost adsorbents, research over the last few years has focused on biological residual materials from plants and animal biomass to not only to add value, but to remediate water at a lower cost with the same or improved efficiency as commercially available option. Crustacean shells are among a class of biological residues that are commonly treated as a waste product of the sea food industry. However, potential valorization by remediation of heavy metal ions, organic matter, and anionic species is a topic of high interest in the current eco-friendly environment. The aim of this review is to provide insight on the state of the art of crustacean shells for addressing water remediation and to offer some perspective regarding challenges and the future of this type of biomass., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The photocatalytic degradation of sulfanethazine (SMT), one of the sulfonamide antibiotics, in aqueous solution by TiO2 was investigated. The time courses of SMT concentration, the amount of non-purgeable organic carbon, and the concentrations of ions such as SO4(2-), NH4(+), and NO3(-) formed during the photocatalytic reaction were measured and the structures of seven intermediates formed with the disappearance of SMT were also estimated by LC/MS/MS analyses. In addition to that of SMT, the decomposition behaviors of model compounds sulfanilic acid (SA) and 4-amino-2, 6-dimethylpyrimidine (ADMP) were investigated using the TiO2/UV system. The observed photocatalytic degradation behaviors of SMT, SA, and ADMP gave new insight into the degradation pathway of SMT. Especially, the formation of p-aminophenol during SMT decomposition, which until now has not been reported in previous studies concerning the photocatalytic decomposition of SMT and other sulfonamide antibiotics. These results indicate the existence of a novel photocatalytic degradation pathway for sulfonamides. The direct substitution of the sulfonamide group with a hydroxyl group is suggested., (Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.)

This work assesses the effects of white rice husk ash (WRHA) as pozzolanic material, virgin kraft pulp (VKP), old corrugated container (OCC) and fibers derived from fiberboard (FFB) as reinforcing agents on some properties of blended cement composites. In the sample preparation, composites were manufactured using fiber-to-cement ratio of 25:75 by weight and 5% CaCl(2) as accelerator. Type II Portland cement was replaced by WRHA at 0%, 25% and 50% by weight of binder. A water-to-binder ratio of 0.55 was used for all blended cement paste mixes. For parametric study, compressive strength, water absorption and density of the composite samples were evaluated. Results showed that WRHA can be applied as a pozzolanic material to cement and also improved resistance to water absorption. However, increasing the replacement level of WRHA tends to reduce the compressive strength due to the low binding ability. The optimum replacement level of WRHA in mortar was 25% by weight of binder; this replacement percentage resulted in better compressive strengths and water absorption. OCC fiber is shown to be superior to VKF and FFB fibers in increasing the compressive strength, due to its superior strength properties. As expected, the increase of the WRHA content induced the reduction of bulk density of the cement composites. Statistical analysis showed that the interaction of above-mentioned variable parameters was significant on the mechanical and physical properties at 1% confidence level., (Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.)

Concerns over possible gaseous emissions from lignosulfonate dust suppressant agents used on dirt roads prompted an investigation into the possible release of sulfur dioxide and organic vapors. Emissions from eight commercial lignosulfonates products applied to three different soil types were measured in environmental chambers. It was determined that except under extreme soil pH conditions (<1), the release of sulfur dioxide from the application of lignosulfonates to roads is essentially non existent. The odor associated with the application was found to be due to trace amounts of organic compounds mainly of the furfural variety. Levels of odor compounds in these products was significantly lower than the previously reported values for spent sulfite liquors because the majority were removed during processing operations prior to sale.