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This study explored the efficacy of red mud, an aluminum production by-product, as an adsorbent for Pb(II) ion removal from contaminated water and assessed the adsorption isothermal model and kinetics. Red mud, characterized by its richness in oxide minerals with reactive surfaces, has potential for heavy metal adsorption, but its capacity for larger ions like Pb(II) is limited. This research aimed to enhance red mud's adsorption properties through modification with ascorbic acid. The modification process involved heating a mixture of red mud and ascorbic acid to its boiling point, followed by the formation of adsorbent beads using red mud and Na-alginate mixture dropped into a 2 % CaCl2 solution at -2 °C. The beads were tested over varying durations ranging from 30 to 210 min. The results indicated that ascorbic acid modification led to the transformation of minerals in red mud, improving its pore diameter, pore volume, and specific surface area of the adsorbent. The modified and unmodified red mud adhered to both Langmuir and Freundlich isotherms, with R² values converging to one, and displayed pseudo-second-order kinetics. Notably, the introduction of ascorbic acid augments the adsorption efficacy of red mud for Pb(II) ions from 84.8 % to a compelling 99.3 %. This underscores the augmented capability of ascorbic acid-modified red mud, highlighting its prospective applicability as a potent adsorbent in the remediation of heavy metalcontaminated water. [ABSTRACT FROM AUTHOR]

This study investigates the viability of utilizing microcellulose extracted from pineapple peel waste as a sustainable and cost-effective matrix material for polypyrrole (PPy)-based capacitors. A novel PPy/microcellulose composite was synthesized with varying pyrrole volumes (1-2 mL) and characterized using Fourier Transform Infrared (FTIR) and Xray diffraction (XRD) analyses. FTIR analysis confirmed successful cellulose isolation, while XRD indicated a similarity between the extracted pineapple peel and commercial cellulose. Capacitor cells were fabricated using the synthesized composites, and their capacitance performance was evaluated. Notably, cells containing 2 mL of PPy exhibited the highest capacitance values. Additionally, the source of cellulose had minimal influence on the resulting capacitance. This study suggests that microcellulose derived from pineapple peel waste holds promise as a sustainable alternative to traditional matrix materials for high-performance capacitors. [ABSTRACT FROM AUTHOR]

A major challenge in developing countries concerning domestic wastewaters is to decrease their treatment costs. In the present study, a new cost-effective reactor called gradual concentric chambers (GCC) was designed and evaluated at lab-scale. The effluent quality of the GCC reactor was compared with that of an upflow anaerobic sludge bed (UASB) reactor. Both reactors showed organic matter removal efficiencies of 90%; however, the elimination of nitrogen was higher in the GCC reactor. The amount of biogas recovered in the GCC and the UASB systems was 50% and 75% of the theoretical amount expected, respectively, and both reactors showed a slightly higher methane production when the feed was supplemented with an additive based on vitamins and minerals. Overall, the economical analysis, the simplicity of design and the performance results revealed that the GCC technology can be of particular interest for sewage treatment in developing countries. [ABSTRACT FROM AUTHOR]