International Journal of Chemical Engineering

Microbial fuel cells (MFCs) have emerged as a viable method for bioremediation of toxic metals while also producing energy. In this paper, we examine the issue of organic substrate as a source of metabolism for microbe growth in MFC, as well as its significance for metal ion degradation in tandem with energy production. This study focused on the use of commercial sugar as an organic substrate in a single-chamber MFC. The MFC was operated for 27 days, with the highest voltage of 150 mV achieved on day 12, and toxic metal bioremediation efficiencies of 89%, 76.45%, and 89.45% for Pb²⁺, Cd²⁺, and Hg²⁺, respectively. Every 24 hours, the organic substrate (sugar solution) was fed into the cell. This study’s mechanism of metal ion degradation and electron transport is also thoroughly described. In addition, some future views have been highlighted.

A finite difference computational study is conducted to assess the influence of thermodiffusion and chemical reaction on unsteady free convective radiated magnetohydrodynamic flow past an exponentially accelerated inclined permeable plate embedded in a saturated porous medium of uniform permeability with variable temperature and concentration. The governing nondimensional set of coupled nonlinear partial differential equations with related initial and boundary conditions are solved numerically by using the accurate and efficient DuFort–Frankel’s explicit finite difference method. The physical features of fluid flow, heat, and mass transfer under the influence of the magnetic field, angle of inclination, plate acceleration, radiation, heat source/sink, thermodiffusion, chemical reaction, and time are scrutinized by plotting graphs and then discussed in detail. It was found that the effective magnetic field and angle of inclination tend to decline the fluid motion, whereas the reverse result is detected by increasing the porosity parameter and plate acceleration. The velocity and temperature of the fluid lessen with increasing the radiation parameter. The effect of thermodiffusion raises the fluid velocity and concentration, whereas a chemical reaction has the opposite impact. The Nusselt number increases with increasing the radiation parameter and time. Increasing chemical reaction and time causes to improve the Sherwood number. This kind of problem finds momentous industrial applications such as food processing, polymer production, inclined surfaces in a seepage flow, and design of fins.

Increased urbanization and consumerism have resulted in the excessive release of food waste and municipal solid waste. Such wastes contain abundant organic matter that can be transformed into energy, addressing the twin challenges of waste management and energy insecurity. In recent years, different studies have investigated ways of producing biogas through the codigestion of organic wastes. In this work, different food wastes were codigested and the biogas yield was determined. The effect of feedstock mixing ratios, temperature, and pH was studied. A mixing ratio of 1 : 1 produced the highest biogas yield (2907 ± 32 mL), nearly twice, which was obtained at a ratio of 1 : 4 (1532 ± 17 mL). The biogas yield increased with the temperature rise. The lowest yield of 2907 ± 32 mL was obtained at 20°C, while the highest yield of 4963 ± 54.6 mL was obtained at 40°C. Regarding pH, the yield was 2808 ± 31 mL at pH 6.5 and 7810 ± 86 mL at pH 7.3. This indicated a 178.1% increase in the biogas yield. The CN ratio for tuber waste and fruit waste was 18 and 28, respectively, while the corresponding pH was 6.7 and 6.9. A positive synergy index of 4.5 was obtained, which is higher than what is reported in the literature of codigested substrates. Irish potato peels and banana peels produced the highest biogas yield and are recommended for use as codigested feedstock.

Microbial fuel cell (MFC) is a method that is both effective and environmentally friendly for producing renewable electricity. Several studies have shown that one of the major challenges is the generation of electrons as a result of poor exploitation of organic substrates. One of the most talked about issues in modern molecular fusion is the reutilization of biological organic waste in an MFC. In this article, the effective utilization of domestic organic waste as an organic supply for bacterial species to generate energy was highlighted. The findings that were obtained corresponded to the one-of-a-kind MFC operation in which a voltage of 110 mV was generated in a time span of 12 days during operation with an external resistance of 500 ῼ. With an internal resistance of 117 ῼ, the maximum power density and the current density were recorded 0.1047 mW/m² and 21.84 mA/m², respectively. According to the results of the biological study, strains of bacteria such as Pseudomonas aeruginosa, Acinetobacter schindleri, and Pseudomonas nitroreducens are the ones responsible for producing energy. In addition, final remarks with proposals for the future have been enclosed.

Backgroundand Aim. Natural organic matter (NOM) has become one of the most serious environmental problems due to its persistence in aqueous solutions and the risk of carcinogenesis. In this study, the removal efficiencies of real and synthetic humic acid (HA) by multi-walled carbon nanotubes (MWCNTs) coated with iron oxide were evaluated. Materials and Methods. The MWCNs were synthesized and coated with iron oxide. In addition, the effects of pH, contact time, mixing speed, and adsorbent dose on the removal efficiency of NOM by MWCNTs-Fe₃O₄ were studied. Then, the removal efficiency of NOM from real samples was investigated at optimal conditions. The MWCNT-Fe₃O₄ was characterized by scanning electron microscopy (SEM) test and X-ray diffraction (XRD), respectively. Data analysis was performed using Minitab software based on the Taguchi method. Results. The results showed that MWCNTs were coated with Fe₃O₄. The SEM test shows particle (MWCNTs-Fe₃O₄) size in the range of 48–143 nm, and the particles have uniform spherical shapes. Enix software was used to identify the phase in this sample. The conditions including , mixing speed = 120 rpm, adsorbent dosage = 1.5 g·L⁻¹, and contact time = 90 minutes were selected as optimal for NOM adsorption. The mean removal efficiencies of NOM in synthetic samples at 5, 10, and 20 mg·L⁻¹ concentrations were 86.6%, 84.87%, and 95.41%, respectively. In addition, the mean removal efficiency of NOM in Choghakhor Wetland was 77%. Conclusion. Our findings demonstrated that the MWCNTs-Fe₃O₄ can be potentially used as an adsorbent for removing natural organic matter (HA) from aqueous solutions.

The large volume of tire waste generated globally poses a major waste disposal problem. In the natural environment, disposed of tires do not degrade easily, but they can be processed through pyrolysis, to get char, gas, and oil. In this study, tire pyrolysis was done using 0.00%, 1.50%, 2.50%, 5.00%, 7.50%, and 10.00% sodium carbonate catalyst in the feed material to produce oil. An evaluation of the effects of the catalyst on the cetane index, calorific value, pH level, and flash point of tire pyrolytic oil (TPO) was carried out since these are the essential properties in relation to safety in its handling and efficiency in engine performance and operation. There was a decrease in the calorific value by 3.09%, the flash point by 37.25%, and the cetane index by 71.2% with increasing catalyst percentage, while the pH was found to increase by 19.78% (between 0.00 and 5.00% sodium carbonate catalysts) and then decreased when more than 5.00% of the catalyst was employed. These results will provide theoretical information that will guide its handling and usage as fuel.