Energy crisis and solid waste management have remained challenging issues for authorities in Pakistan. These issues tend to rise with increasing population and economic growth of the society. Therefore, environmentally sustainable waste‐to‐energy program must be part of the waste management system since they may substitute fossil fuels with renewable energy sources by enabling energy recovery instead of landfill of solid wastes. In this work, the combustion characteristics of fossil fuel (coal) and solid wastes such as municipal solid waste (MSW) and refuse‐derived fuel (RDF) were investigated by thermogravimetric analysis (TGA) to compare their thermal decomposition behavior. Furthermore, proximate and ultimate analyses of these samples were carried out along with their heating values. The TGA profiles of samples indicate low reactivity of coal, whereas solid wastes present greater reaction rate reflecting their low ash and high volatile contents. It was found that the heating value of RDF sample was close to that of coal. The obtained thermal data were used to calculate the kinetic parameters using Arrhenius and Coats‐Redfern models with different reaction mechanisms. According to these models, the fuels could be arranged in order of activation energy as coal > RDF > MSW. The percentage difference between activation energy values found from Arrhenius and Coats‐Redfern models was in the range of 4.1%‐26.5%. However, the Coats‐Redfern model exhibited consistency in activation energy values, followed by a high value of R2. These results of the TGA could be very helpful to predict the combustion dynamics and confirm that MSW and RDF may be used as sustainable fuels, to meet the prevailing challenges of the energy crisis and solid waste management.
The thermal characteristics and kinetic behavior of various solid wastes, including refuse‐derived fuel (RDF) and municipal solid waste (MSW), were investigated as a potential renewable energy source, in comparison with low‐rank coal. The experimental data were obtained in nonisothermal conditions through TGA analysis at specific heating rates. In addition to thermal characteristics of solid fuels, four isoconversional (model‐free) kinetic methods: a: Kissinger‐Akahira‐Sunose (KAS), b: Flynn‐Wall‐Ozawa (FWO), c: Friedman, and d: Vyazovkin were applied to calculate activation energies. In case of solid wastes, it is possible to say that the trend of activation energies of all isoconversional methods remains almost same in the selected region of conversion (0.1‐0.6 and 0.7‐0.9). Whereas in case of coal, Friedman model exhibits lower and inconsistent values of activation energy than others selected isoconversional methods. The experimental and modeling results revealed that that solid wastes (RDF and MSW) can be promising alternative energy sources to encounter energy crisis and uncontrolled waste disposal issues.
This article provides a comprehensive review of the recent progress in the application of advanced two-dimensional nanomaterials (2DNMs) in membranes fabrication and application for water purification. The membranes fouling, its types, and anti-fouling mechanisms of different 2DNMs containing membrane systems are also discussed. The developments in membrane synthesis and modification using 2DNMs, especially graphene and graphene family materials, carbon nanotubes (CNTs), MXenes, and others are critically reviewed. Further, the application potential of next-generation 2DNMs-based membranes in water/wastewater treatment systems is surveyed. Finally, the current problems and future opportunities of applying 2DNMs for anti-fouling membranes are also debated.
Plant-mediated synthesis of nanoparticles exhibits great potential to minimize the generation of chemical waste through the utilization of non-toxic precursors. In this research work, we report the synthesis of magnesium oxide (MgO) and cobalt oxide (Co3O4) nanoparticles through a green approach using Manilkara zapota leaves extract, their surface modification by polyaniline (PANI), and antifungal properties against Aspergillus niger. Textural and structural characterization of modified and unmodified metal oxide nanoparticles were evaluated using FT-IR, SEM, and XRD. The optimal conditions for inhibition of Aspergillus niger were achieved by varying nanoparticles’ concentration and time exposure. Results demonstrate that PANI/MgO nanoparticles were superior in function relative to PANI/Co3O4 nanoparticles to control the growth rate of Aspergillus niger at optimal conditions (time exposure of 72 h and nanoparticles concentration of 24 mM). A percentage decrease of 73.2% and 65.1% in fungal growth was observed using PANI/MgO and PANI/Co3O4 nanoparticles, respectively, which was higher than the unmodified metal oxide nanoparticles (67.5% and 63.2%).
A class of intractable bio accumulative halogenated compounds polybrominated diphenyl ethers (PBDEs) was studied. Specifically, PBDEs and dechloran plus (DP) contamination in wheat and the assaulted environment—agricultural soil and dust—from metropolitan cities of Pakistan was the focus. The exposure of brominated flame retardants (BFRs) to humans, their probable toxicological impact on health, source apportionment, and the spatial tendency of BFRs were studied. Chromatographic analysis was performed, and concentrations (ng g−1) of ΣPBDE and ΣDP in soil, dust, and cereal crops were estimated in a range from 0.63 to 31.70 n.d. to 6.32 and n.d. to 3.47, respectively, and 0.11 to 7.05, n.d. to 4.56 and 0.05 to 4.95, respectively. Data analysis of source apportionment reflected that the existence of solid and e-waste sites, long-range transport, urban and industrial fraction can be the potential source of PBDE and DP pollution. Moreover, potential hazardous risks to human health across the study area via the dietary intake of cereal foods were deemed trifling, and were gauged on the basis of existing toxicological data.
In this study, a low-cost, efficient, and environmentally friendly anaerobic sludge process for the treatment of industrial beverage wastewater was investigated to analyze the effect of bacteria growth on the degradation of organic matter (chemical oxygen demand). Additionally, the mechanism, interactions between the microbe’s growth, and operating conditions of an anaerobic batch reactor along with the wastewater treatment efficiency were evaluated via microbial kinetics. The kinetic coefficients based on chemical oxygen demand (COD) by conventional techniques such as kinetic coefficients growth yield (0.46 mg VSS/mg COD), saturation coefficient (3500 mg/L COD), the maximum rate of substrate utilization per unit mass of biomass (0.0066 mg/L COD), growth rate by Monod equation, M (0.03833 L/h), and maximum growth rate, μm (0.03672 L/h) were calculated. The results show a higher rate of substrate degradation (0.54 day−1) due to the high COD removal efficiency (CRE) of 99.31% during 13 days that was achieved, which can be attributed to the active involvement of anaerobic microbes in the process of degradation. Based on these results, it can be concluded that the current study can be used as an effective way to analyze the industrial beverage wastewater at commercial levels.