Waste Disposal & Sustainable Energy最新文献

In this study, acrylic fibers waste blended with different ratios of nanochitosan (0.5%, 1%, 2% and 4%, in weight) were converted into antifouling ultrafiltration nanocomposite membranes using a phase separation technique for the remediation of Congo red (CR) and crystal violet (CV) dyes from water. The fabricated nanocomposite membranes were investigated using Fourier Transform Infrared (FTIR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscope (SEM). The membrane hydrophilicity was estimated using contact angle measurements, which revealed that the 4% loaded nanochitosan had the highest hydrophilicity. Additionally, the water uptake, porosity, water contact angle and water flux of the nanocomposite membranes were assessed. The membrane filtration performances were explored for the removal of CR and CV as anionic and cationic dyes, respectively, at different concentrations and various applied pressures (1 bar to 4 bar). The experimental data revealed a high rejection (R) performance for CR (R≃100%) with a high water flux of about 150 L/(m²·h) to 183 L/(m²·h) for the optimized membrane with 2% nanochitosan at an applied pressure of 4 bar. The rejection for CV showed a variant rejection (70%–99%) at different dye concentrations with fluxes ranging from 93.6 L/(m²·h) to 149.5 L/(m²·h) for the same composite membrane. The composite membrane showed enhanced flux recovery after fouling by bovine serum albumin and was resistant to widespread gram-positive (Staphylococcus aureus) bacteria.

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Iron element is known to be an effective additive for accelerating the anaerobic digestion (AD) process for treating organic wastes. However, the effects of different kinds of iron additives on food waste (FW) and sewage sludge of co-digestion process have not been yet investigated thoroughly. This study aimed to elucidate how different kinds of iron components affect methane production during FW and sewage sludge anaerobic co-digestion (co-AD) process and to investigate the possible mechanism of Fe amendment. Experimental results revealed that Fe amendment could effectively promote the substrate degradation and methane production, and FeCl₃ amended group presented the best digestion performance, boosting the methane production from 465.9 mL to 2650.4 mL. The results of the excitation-emission matrix fluorescence spectra analysis further supported that Fe supplements facilitated the waste hydrolysis with a higher concentration of dissolved organic matters and thereby more substrates can be used for methane generation. In addition, the activity of coenzyme F420 and direct interspecies electron transfer in FeCl₃ group were 5.82 and 5.89 times higher than those in the control group, respectively, indicating that electron transfer, particularly the interspecies one, was enhanced by Fe amendment. As compared to that in the control group, the increased cytochrome c concentration in Fe amended groups also proved it. Therefore, this study will provide a reference regarding Fe amendment in the co-AD process for FW and sewage sludge.

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Kitchen waste solid residues (KWSR) are secondary organic solid wastes generated from kitchen waste (KW) after oil and slurry separation. In this study, two recycling methods for KWSR were investigated: direct membrane-covered aerobic composting (T1) and a two-stage method combining vermicomposting with membrane-covered aerobic composting (T2). Compared with T1, T2 had a faster increase in pile temperature, a shorter thermal stage, lower greenhouse gas emissions and higher NH₃ emissions. The vermicomposting promoted the formation of humus and shortened the maturation time during aerobic composting, resulting in a shorter treatment period for T2 (18 d) than for T1 (21 d). The initial bacterial communities of T1 and T2 were significantly different, but they became similar as composting progressed. The economic feasibility analysis showed that 1000 kg of KWSR generated a profit of 285 CNY using the T2 method, which was higher than that of T1 (36 CNY). The outcomes of the present study provide an improved strategy for the management of KWSR.

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Slum dwellers often fail to expend enough on waste disposal to have a healthy life, and remittances provide funds for a household to expend on the betterment of life conditions. This paper examines the impact of remittances on total monthly waste disposal expenditures and the impact of better waste disposal on monthly health expenditures among slum households in Bangladesh. Propensity score matching was adopted as an identification strategy to reduce selection bias. In this study, remittance includes both remittances received from within and outside Bangladesh. Remittance receipt equals 1 if a household receives remittances from within and/or outside of Bangladesh. Our results show that remittances increase expenditures on waste disposal by 28.77% to 32.74% among slum households in Bangladesh. Waste disposal expenditure is considered as an indicator of better waste disposal. Furthermore, we find that better waste disposal reduces total outpatient expenditures. A reduction in outpatient expenditure indicates that waste disposal results in better health conditions for slum dwellers. The findings of this study can be connected to Sustainable Development Goal 11, which targets sustainable cities and communities and suggests that remittances are a bottom-up financial mechanism for improving waste disposal at the micro level to improve health status.

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This paper reviews recent advances in the use of graphite carbon nitride (g-C₃N₄)-based composite photocatalysts for antibiotic and dye degradation and hydrogen production. It also discusses the structure, synthesis, modification, morphology, doping, preparation, and application of a particular subject and evaluates the advantages and disadvantages of different morphologies and preparation processes. The photocatalysts based on g-C₃N₄-based composites have demonstrated great potential. The g-C₃N₄ has been modified and tailored into various novel structures and morphologies to improve its efficiency in the photocatalytic degradation of pollutants. The techniques such as doping, metal deposition, heterojunction formation, and structural tuning enhance the rate of light absorption, charge transfer, and charge separation of g-C₃N₄. This leads to improved photocatalytic performance for antibiotic and dye degradation and hydrogen production.

Chicken manure (CM) is one of the most common animal wastes produced worldwide. The conventional application of CM is as a fertilizer; however, in the present study, we introduce an approach for the straightforward and affordable use of CM for fuel cell applications. It reports the functionalization of carbon nanofibers (CNFs) using CM to confer multiple functionalities. The elements that make up the functionalized CNF are nitrogen (7.40%, atoms ratio, the same below), oxygen (6.22%), phosphorous (0.30%), and sulfur (0.02%), etc., according to energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy studies. It has been verified that following treatment with CM, the morphology of the CNFs remains the same. The CM-modified CNFs exhibit a higher electrocatalytic activity (onset potential: −0.0756 V; limiting current density: 2.69 mA/cm²) for the oxygen reduction reaction (ORR) at the cathode of a fuel cell. The electron transfer number for this sample is 3.68, i.e., the ORR favours a four-electron pathway like Pt/C. The direct method of functionalizing the CNF is more effective; however, treatment of CNFs with Triton X-100 prior to functionalization shields their otherwise exposed open edge sites and in turn affects their ORR activity. A large surface area (99.866 m²/g), the presence of multiple functional elements (oxygen, nitrogen, phosphorous, sulfur, etc.), surface charge redistribution and induced donor–acceptor interactions at the surface of CM-modified CNFs contribute to their enhanced electrochemical activity. This preliminary study reports the suitability of a facile and economical approach for treating CM for the most advanced clean energy applications. Hopefully, this study will pave the way for cutting-edge methods for handling other biowaste materials as well.

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