AbstractThis research aims to develop a conceptual framework and assessment tool to assess sustainability of Multifunction Constructed Wetlands Projects (MCWP). First, by literature review to analyze the main points and identify the gaps in existing research to what concerns viewing constructed wetlands as multifunction sustainable landscape projects. To assess the performance of MCWP, urban sustainability indicators are proposed examining interconnections between environmental, economic and social aspects and their effects on each other. 12 environmental, 9 socio-cultural and 7 economic indicators are selected according to their relevance to the United Nations and National Sustainable Development Goals, the impacts of their weights according to a distributed questionnaire showed these percentages: environmental aspects 42%, Socio-cultural aspects 29% and the economic aspects 28%. Also, performance-oriented assessment tools for MCWPs were designed for wastewater treatment. The impacts of proposed indicators are then assessed using the adapted Leopold Matrix method. Hence, this study aims to establish an assessment model to evaluate the sustainability features of MCWPs, by proposing sustainability indicators to be assessed by measurement metrics and respective weights for indicators and sub-indicators.

Abstract With the growth of the industrial aluminum smelting sector, and the increasing proportion of incineration treatment in the field of waste management and disposal, there has been a corresponding increase in the production of secondary aluminum dross (SAD) and municipal solid waste incineration fly ash (MSWIFA) annually. In this research, ceramsite is prepared using SAD, MSWIFA, and municipal solid waste incineration bottom ash (MSWIBA) as raw materials. This study explores the impact of various factors on the mechanical properties of ceramsite and their mechanisms under different conditions, including sintering temperature, raw material ball particle size, raw material silica-alumina ratio, and sintering time. Single-factor experiments demonstrate that the compressive strength of ceramsite initially follows a non-linear ascending trend with increasing sintering temperatures. Additionally, the strength is enhanced with reductions in particle size of the raw material balls, prolongation of the sintering time, and a reduction in the silica-to-alumina ratio of the raw materials. Orthogonal experiments reveal the ideal preparation conditions for ceramsite as follows: a preheating temperature of 400 °C, a preheating duration of 20 min, a sintering temperature of 1270 °C, and a duration of 30 min. Under these conditions, the optimal composition ratio of ceramsite is Si:Al = 3, and the ideal particle size is 0.5 cm. Analysis through X-ray diffraction and scanning electron microscopy revealed the formation of new mineral phases such as sodium feldspar and potassium feldspar in the ceramsite, which display a dense structure under microscopic observation. These contribute positively to the mechanical properties of the ceramsite. Fourier-transform infrared spectroscopy analysis indicates that at a sintering temperature of 1260 °C or when the raw material ball size is 2 cm, the [SiO4] tetrahedral bands shift to higher wavenumbers, enhancing the degree of polymerization of the glass network in the ceramsite, thereby strengthening its compressive strength. As the silica-alumina ratio of the raw materials decreases and the sintering duration extends, the [SiO4] tetrahedral bands continue to shift to higher wavenumbers, further enhancing the compressive strength of the ceramsite.

This study investigated the effects of different pyrolytic temperatures on Pb(II) adsorption from synthetic wastewater using waste bamboo chopsticks (BCs) produced via conventional and microwave-assisted pyrolysis. Eleven biochars were prepared and characterized using Brunauer‒Emmett‒Teller analysis, elemental analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy. Thereafter, the selected biochars were further analyzed through batch adsorption studies. The influence of adsorbent dose, initial Pb(II) concentration, and contact time on the removal of Pb(II) from synthetic wastewater was studied. For the adsorbent dose, good removal efficiencies and adsorption capacities were observed at an adsorbent dose of 2 g L−1 and at an initial concentration of 50 mg L−1. For the initial Pb(II) concentration, high adsorption capacities and removal efficiencies were observed at 50 mg L−1 for concentrations ranging from 5 to 100 mg L−1. The contact time reached equilibrium within 24 h, where BC 450 W had the highest removal efficiency of 99.9%. Furthermore, the Langmuir isotherm model best represented the adsorption of Pb(II) onto biochar, with the highest qm of 81 mg g−1 at R2 = 0.978. Pseudo-second-order kinetics provided the best overall fit for the adsorption kinetics of the biochars, with R2 = 1.00 for BC 450 W and BC 700 °C. Among the many chemisorption processes identified in previous studies, surface complexation has been identified as a possible adsorption mechanism for Pb(II) on the biochars produced. BC biochar could be a sustainable means for remediating polluted mine water and managing waste.

SiO2 nanoparticles (SNPs), which are abundant in water and are used for various applications, for example, as food additives and anticaking agents, are of growing concern because of rising exposure to human health. Research has reported low potential side effects in animal models treated with SNPs; however, a few in vivo studies have shown cause for concern. Presently, high-fat foods have changed our lives and increased the incidence rates of fatty liver, obesity, and overweight, and high-fat foods issue is prevalent in our modern society. To understand the rising SNPs exposure in life and modern dietary habits combined effect, we design experiments to study this research. Institute of Cancer Research mice fed a normal or high-fat diet were treated with different concentrations of SNPs for long-term effects. Blood and liver tissue were collected and prepared for blood biochemical assays, histology analysis, silicon and triglycerides (TGs) accumulation, immunohistochemistry, fibrosis staining, and terminal deoxynucleotidyl transferase dUTP nick-end labeling staining to analyze the influence of the combination of SNPs and a high-fat diet. This research found that the presence of SNPs in drinking water with the consumption of a high-fat diet was associated with the accumulation of SNPs and TGs in liver tissue, elevated aspartate aminotransferase and alanine aminotransferase levels in serum, activation of fibrosis and inflammation, increased oxidative stress through 4-hydroxynonenal, and the development of liver steatosis. The results showed that the long-term effect of SNPs in drinking water might induce liver steatosis, particularly under modern dietary habits such as a high-fat diet. This study investigated the interactions between environmental nanoparticles, such as the long-term risk of exposure to SNPs, and dietary factors, suggesting a significant risk to liver health, especially in human health.

Chitosan is a biopolymer derived from chitin, which is the second most abundant and renewable polymer in nature after cellulose. Low-molecular-weight chitosan (LMWC) is the degradation product of chitosan through depolymerization. Compared with conventional chitosan, LMWC is considered as one of the most promising functional materials due to its characteristics of lower polymerization degree, lower viscosity, good water solubility, reactivity and degradability. This review focused on the preparation and characterization methods as well as the application in environmental remediation of LMWC. The three main methods of LMWC preparation including chemical, physical and enzymatic methods were summarized and compared in this paper. The mechanism, advantages and disadvantages of various preparation methods were also discussed. In addition, the applications of LMWC in environmental fields such as water treatment, soil remediation and air purification were briefly reviewed. With the continuous progress of science and technology and the improvement of environmental awareness, it is believed that more efficient, economical and environmentally friendly chitosan degradation methods will be developed, providing strong support for the wide application of LMWC in the field of environmental protection.

Algogenic organic matter (AOM) generated from cyanobacteria-impacted reservoirs poses a significant risk to drinking water. This study aimed to investigate the molecular degradation signature of Microcystis aeruginosa (MA)-derived AOM by electrochemical oxidation and the corresponding disinfection by-product formation potential (DBPFP). Boron-doped diamond (BDD)-based electro-oxidation (EO) and electro-Fenton (EF) were implemented at pH 3 and 10 mA cm−2 within 1 h. The fluorophore of extracellular organic matter (EOM), the mixture of EOM and intracellular organic matter (IOM), were characterized, and their corresponding molecular weight (MW) were fractionated. The results showed that dissolved organic carbon (DOC) degradation efficiency for BDD-EF treatment is superior and maintains DOC attenuation up to 84% for the EOM suspensions alone, while a low degradation efficiency occurs for IOM-EOM mixture. In contrast, BDD-EO exhibits a maximum DOC degradation around 66% for EOM suspensions alone, but DOC reduction is as low as 20% for IOM-EOM mixture. The H2O2 generated by BDD-EO preferentially degrades humic acid-like substances in EOM suspensions, whereas BDD-EF effectively degrades multiple fluorescent AOM by •OH. For IOM-EOM mixture, BDD-EO efficiently decomposes humics, but BDD-EF preferentially minimizes soluble microbial product-like and aromatic protein-like substances. Meanwhile, BDD-EF favors degrading biopolymers, humics, and low-MW substances, while BDD-EO merely degrades partial biopolymers and humic substances. After either EF or EO, specific DBPFP decreases as EOM presents alone where the toxicity of corresponding DBPs is mitigated effectively, instead the increased specific DBPFP appears for IOM-EOM mixture where the toxic potency ([DBP]/LC50) of corresponding DBPs increases. In summary, EO and EF are powerful in attenuating MA-derived DBP precursors of EOM in the absence of IOM, depending on the molecular signature.

Heavy metal pollution is a global environmental issue, and microorganisms play a crucial role in the bioremediation of heavy metal-contaminated wastewater. The study isolated heavy metal-resistant bacterium and observed their absorption ability toward Pb2+, Cd2+ and Zn2+. We isolated Agrobacterium tumefaciens S12 from acid mine drainage. The various factors influencing its adsorption performance, including pH, biomass dosage, initial metal ion concentration, and adsorption temperature, were investigated in detail. Chemisorption controls the adsorption rate due to the results better fitted by pseudo-second order kinetics. The maximum adsorption capacities of Pb2+, Cd2+ and Zn2+ on A. tumefaciens S12 were 234, 58 and 51 mg g−1 at 30 °C from Langmuir isotherm, respectively. The adsorption processes for the three heavy metal ions were spontaneous and exothermic in nature. In bimetallic systems, biosorption of Pb2+ ions was preferential to that of Cd2+ and Zn2+. Furthermore, scanning electron microscopy coupled to energy dispersive spectroscopy, Fourier-transform infrared spectra and X-ray photoelectron spectroscopy analysis demonstrated that the adsorption mechanisms include ion-exchange, complexation interaction between the heavy metal ions and the functional groups on the surface of biomass. The obtained results indicated that A. tumefaciens S12 can be applied as an efficient biosorbent in bioremediation technology to sequestrate heavy metal ions from aqueous solution.

Graphite has been a critical raw material in recent years due to its high economic importance and high risk of supply disruptions. The traditional source of graphite is natural graphite ores; however, the production of natural graphite ores is controlled by few countries. It is thus important to find an alternative source of graphite, and steelmaking byproducts, such as dust and slag, can be considered because of their high potential for the recovery of kish graphite. The original kish graphite normally has a low carbon content and large amounts of impurities, and purification is necessary before using kish graphite in industry. The purpose of this study was to recover kish graphite from steelmaking dust by combining multi-stage froth flotation and acid leaching processes. The conditions of acid leaching were examined, and physical auxiliary methods (heating, microwave irradiation, and ultrasonication) were studied. After the multi-stage froth flotation process, the carbon content of the kish graphite was approximately 84 wt%, and Fe, Ca, Al, Na, K, Si, and Mg were the major elements of impurities. The acid leaching process was useful for enhancing the carbon content of the kish graphite and removing the impurities, particularly when using HCl and HBF4. However, HCl should be a more appropriate selection for acid leaching when considering the price of acids. The carbon content of the kish graphite reached ~ 95 wt% when using 1.0 N HCl with ≥ 30 min of reaction time and a ≥ 5 L kg−1 liquid-to-solid ratio. The physical auxiliary methods can further increase the carbon content of the kish graphite. The kish graphite purified by heating 1.0 N HCl at 80 °C for 5 min had the highest carbon content of approximately 97 wt%. The purified kish graphite and the natural graphite had similar crystallinity and lamellar structures, but the purified kish graphite had more structural defects. The recovery of kish graphite from steelmaking dust can obtain valuable materials and should have benefits for the environment.

Cities worldwide are increasingly turning to underground spaces to address the challenges posed by high population density. These subterranean areas are now utilized for various purposes such as offices, shopping malls, subway terminals, and underground sidewalks. However, the semi-closed nature of most underground spaces presents difficulties in ensuring a comfortable environment due to the lack of natural ventilation. This study focuses on a representative underground shopping mall in South Korea, utilizing preliminary surveys and long-term sensor monitoring to identify existing problems. The aging ventilation system was retrofitted to enhance and assess indoor air quality. As a result, concentrations of carbon dioxide, total volatile organic compounds, and radon were reduced by over 33, 74, and 98%, respectively, while particulate matter with a diameter of 2.5 μm or less (PM2.5) concentrations remained the same as before. This not only contributed to maintaining proper indoor air quality, but also led to a reduction in total energy consumption. The goal of this project is to improve air quality in facilities located in underground spaces, such as underground shopping malls, where indoor air quality management is challenging, thereby creating a safe and healthy environment for users and enhancing the overall functionality of the facility.

India's rapid industrialization has led to an increase in waste generation, necessitating efficient disposal methods. This research addresses this challenge by exploring the use of Common Effluent Treatment Plant (CETP) sludge, a hazardous waste, in the production of Controlled Low-Strength Materials (CLSM). The study aims to mitigate the environmental impacts associated with CETP sludge disposal while providing a sustainable solution. To assess the feasibility of this approach, an experimental program was conducted with variations in the mix ratio of CETP sludge and slag sand, a byproduct of steel production. The properties of the produced CLSM, such as flowability and unconfined compressive strength (UCS), were thoroughly examined using Scanning Electron Microscopy, X-ray Diffraction, and X-ray Fluorescence analyses. The results reveal that the CLSM produced with CETP sludge and slag sand exhibits promising performance, with excellent flowability and UCS values ranging from 1.8 to 5.5 MPa. This research underscores the potential of waste materials in creating sustainable and environmentally friendly construction materials, contributing to effective waste management practices and sustainable industrial growth.