Waste Disposal & Sustainable Energy最新文献

Antibiotics and their metabolic byproducts are found in wastewater and natural water as a result of increased consumption, posing a major threat to humans and other living organisms. One of the most promising methods for their removal is adsorption using biochar because it offers excellent adsorption potential and is both affordable and environmentally beneficial. However, raw biochar frequently has a low adsorption capacity due to its limited pore structure and unfavorable surface characteristics. Biochar surface modifications using modifiers such as H₃PO₄, KOH, and NaOH have improved the surface area and thereby the adsorption capacity. Experimental methods for assessing the effectiveness and adsorption mechanism of modified biochar are costly and time-consuming. Density functional theory (DFT) was used to investigate the interfacial interactions and adsorption mechanism of tetracycline (TC), a widely used antibiotic for personal care and veterinary medication, on unmodified and modified biochar. The DFT calculations showed that the adsorption energy of TC on unmodified and modified biochar is in the following order: KOH-modified biochar (− 2.38 eV)<NaOH-modified biochar (− 2.20 eV)<unmodified biochar (− 1.56 eV)<H₃PO₄-modified biochar (5.48 eV). The lower adsorption energy is associated with a stronger and more stable interaction between the adsorbent and the contaminant. This suggests that the adsorption of TC on KOH-modified biochar is more prolific and stable compared to the other biochar. This study provides an understanding of the mechanism underlying the adsorption of TC by modified biochar and can be used as a guide to screen for biochar with promising adsorption potential prior to experimental efforts.

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Pharmaceutical is one of the noteworthy classes of emerging contaminants. These biologically active compounds pose a range of deleterious impacts on human health and the environment. This is attributed to their refractory behavior, poor biodegradability, and pseudopersistent nature. Their large-scale production by pharmaceutical industries and subsequent widespread utilization in hospitals, community health centers, and veterinary facilities, among others, have significantly increased the occurrence of pharmaceutical residues in various environmental compartments. Several technologies are currently being evaluated to eliminate pharmaceutical compounds (PCs) from aqueous environments. Among them, adsorption appears as the most viable treatment option because of its operational simplicity and low cost. Intensive research and development efforts are, therefore, currently underway to develop inexpensive adsorbents for the effective abatement of PCs. Although numerous adsorbents have been investigated for the removal of PCs in recent years, biochar-based adsorbents have garnered tremendous scientific attention to eliminate PCs from aqueous matrices because of their decent specific surface area, tunable surface chemistry, scalable production, and environmentally benign nature. This review, therefore, attempts to provide an overview of the latest progress in the application of biochar for the removal of PCs from wastewater. Additionally, the fundamental knowledge gaps in the domain knowledge are identified and novel strategic research guidelines are laid out to make further advances in this promising approach towards sustainable development.

Solid waste management is a severe challenge in India due to massive and rapid growth in waste generation rates, environmental difficulties, and financial constraints for proper treatment. Poorly managed municipal solid waste (MSW) has substantial negative consequences for society, including financial and aesthetic harm, contamination of natural resources, environmental pollution, and severe health danger. Both qualitative and quantitative factors are required to select the appropriate solid waste treatment and disposal technologies. Multi-Criteria decision-making tools helped in analyzing solid waste in terms of qualitative and quantitative factors. In this paper, seven criteria and their sub-criteria are selected for ranking solid waste treatment and disposal technology using fuzzy-analytic hierarchy process. The results showed that composting is the most suitable option for solid waste treatment and disposal technology, followed by refuse-derived fuel. The incineration and sanitary landfills are the least preferred  MSW management alternatives. The sensitivity analysis reveals a high consistency, robustness, and stability level.

Empty fruit bunch (EFB) is an industrial waste that is abundantly available in Malaysia. Traditionally, EFBs were burned and dumped on the plantation site, resulting in global warming pollution from methane and carbon dioxide. In this study, the EFB was transformed into a high-surface area of activated biochar through a microwave physicochemical approach involving the combination of steam followed by a hydroxide mixture for palm oil mill effluent (POME) treatment. It was found that BET (Brunauer–Emmett–Teller) surface area and total pore volume of activated biochar were 365.60 m²/g and 0.16 cm³/g, respectively. The surface morphology of activated biochar revealed the formation of well-developed pores that can potentially be used as adsorbents to treat POME. The removal efficiency of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) of POME achieved 75%–55%, respectively. This study offers insight into the transformation of industrial waste into value-added products for sustainable environmental remediation.

Intensive land use has several detrimental effects on land function and imposes an undue burden on the environment. Continuous farming and pollution by heavy metals have negatively influenced many soils. Biochar is now gaining attention as a major research subject in the areas of agriculture, environment, and energy as an eco-friendly soil conditioner. The use of biochar for agricultural and environmental purposes has been widely studied and reviewed. Unfortunately, there are few reviews on biochar structures and other biochar uses. This review presents an overview of current developments in the effects of numerous biochar physicochemical properties and biochar uses, such as utilization as a soil microbial activity, contaminant adsorbent, ion exchange, soil amendment, gas storage and water retention. The physical, chemical and biological properties have been discussed following amendments to the soil and conditions of preparation. However, scientific observation and research are required to identify the negative effects of biochar in preparations and applications. It is envisaged that further in-depth studies of biochar amendment will lead to a deeper understanding of biochar's relationships with soils and that reviews of the negative impacts of biochar could reveal ways in which they might be mitigated.

Microwave steam pyrolysis (MSP) is an innovative thermochemical approach to converting biomass into high-quality biochar using steam to improve the dielectric heating of microwave radiation. Biochar shows high fixed carbon and carbon contents at a maximum temperature of 550 °C in 10 min. The MSP achieved a heating rate of 112 °C/min from 200 °C to 400 °C to produce biochar effectively. Furthermore, the thermal properties of biochar in microwave heating were investigated in this study to explore its potential as a microwave heat-absorbent material. Microwave is able to perform volumetric and controllable heating to the biochar. Moreover, biochar shows good microwave heat absorbency, storing and transferring heat effectively. The temperature profile of three different sizes of biochar was investigated to examine the efficiency of biochar in heat absorption from microwave radiation. It was found that the powder form of biochar showed a higher heat transfer rate of 40 °C/min and a low cooling rate of 7.5 °C/min. The presented results are useful for evaluating the application of biochar as a promising medium for heat storage systems.

Alum sludge is a typical by-product of drinking water treatment processes. Most sludge is disposed of at landfill sites, and such a disposal method may cause significant environmental concern due to its vast amount. This paper assessed the feasibility of reusing sludge as a supplementary cementitious material, which could efficiently exhaust stockpiled sludge. Specifically, the pozzolanic reactivity of sludge at different temperatures, the reaction mechanism of the sludge–cement binder, and the resistance of sludge-derived mortar to microbially induced corrosion were investigated. The obtained results indicated that 800 °C was the optimal calcination temperature for sludge. Mortar containing sludge up to 30% by weight showed comparable physical properties at a curing age of 90 days. Mortar with 10% cement replaced by sludge can significantly improve the resistance to biogenic corrosion due to the formation of Al-bearing phases with high resistance to acidic media, e.g., Ca₄Al₂O₇·xH₂O and strätlingite.

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A novel selective catalytic reduction (SCR) catalyst with high catalytic activity on chloroaromatic organics at lower temperatures (160–180 ℃) is critical for municipal solid waste incineration (MSWI) plants. This study prepares a series of honeycomb-type VO_x/TiO₂ catalysts and finally develops a new low-temperature catalyst with high catalytic activity in eliminating chloroaromatic organics. Based on the conversion efficiency (CE) of 1,2-dichlorobenzene (1,2-DCB) and CO₂ selectivity, the optimal VO_x content of 4.06% (in weight) in VO_x/TiO₂ catalyst is first confirmed. By modifying CeO_x and WO_x, a novel honeycomb-type catalyst of VO_x–CeO_x–WO_x/TiO₂ achieves the highest CE (93.1%–93.6%) and CO₂ selectivity (40.9%–60.7%) at 150–200 ℃. It was found that the CeO_x and WO_x can improve the catalytic activity by enriching the surface content of V and O, increasing the proportion of V⁵⁺ and O_surf, enlarging the supply source of reactive oxygen species and their storage capacity, and accelerating the redox cycle of VO_x, CeO_x, WO_x, and reactive oxygen species. This study can guide the development of monolithic low-temperature catalysts with high catalytic activity in eliminating chloroaromatic organics in MSWI flue gas.

Hydrothermal carbonization (HTC) of food waste can produce hydrochar for further utilization as high-quality fuel or carbon materials, but the by-product of liquid effluent, named HTC wastewater, has a high chemical oxygen demand (COD) content and other organic pollutants. This study focused on the feasibility of Fenton oxidation combined with activated carbon (AC) to reduce COD in HTC wastewater. The effects of different parameters including pH, dosage of hydrogen peroxide, molar ratio of Fe²⁺/H₂O₂, and reaction time were tested and discussed. Eventually, through the optimized Fenton oxidation (pH = 3, H₂O₂ dosage = 1.5 mol/L, Fe²⁺/H₂O₂ = 1:15, reaction time = 60 min) combined optimized AC adsorption process (AC dosage = 30 g/L), the COD value reduced from 42,000 mg/L to 3075 mg/L, indicating a COD removal efficiency of 92.7% and a color removal ratio of 91.9%, respectively. The comparison of GC/MS (gas chromatography mass spectrometer) and FTIR (Fourier transform infrared spectrometer) of liquid residual from different treatment methods also indicated that the types of organic substances in HTC wastewater were significantly reduced through Fenton oxidation and AC adsorption.

Coal fly ash (CFA) is the main combustion residue of fine ground coal in the process of coal-fired thermal power generation, and crude glycerol (CG) is the byproduct of biodiesel production. The novel polyurethane/CFA (PU/CFA) foam composites were prepared from CFA and CG. Two kinds of CFA, CFAI and CFAII were used as fillers for the property enhancement of PU/CFA composites, and the effects on foaming behavior and the reinforcement for the PU/CFA composites were investigated. It was found that the addition of CFA can prolong the rising time and tack-free time, and the maximum rising time and tack-free time increased to 40 s and 42 s. Meanwhile, the maximum compressive strength of PU/CFAI and PU/CFAII increased to 0.2186 MPa and 0.2284 MPa with the addition of CFA. The thermogravimetric analysis showed that the PU/CFA composites underwent three stages of thermal decomposition, and the amount of carbon residue increased from 23.11% to 67.91% with increasing CFA dosage. Moreover, the values of the limit oxygen index increased from 21.5% to 23.7% with the incorporation of CFA into the PU foam matrix, indicating that CFA improved the thermal stability and flame retardant performance of the composites. This study provided a new method for the recycling and high-value utilization of CG and CFA.