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This paper addresses the analysis of hydrothermal carbonization of Tetra Pak residues using diluted sulfuric acid to obtain hydrochars for cleaning water polluted by heavy metal ions. The hydrochar samples were prepared under different carbonization conditions, and a detailed study of their composition, textural parameters, and surface functionalities was performed. It was found that the hydrothermal carbonization and dwell time of the Tetra Pak wastes significantly affected the composition of the hydrochars. These hydrochar samples contained oxygenated functional groups and aluminum-silicon moieties that were responsible for the Pb2+, Zn2+, and Hg2+ adsorption. The removal of these heavy metal ions using Tetra Pak hydrochars was an endothermic and multi-ionic process. Hydrothermal carbonization is a promising approach to improve Tetra Pak waste management, generating materials with interesting properties for addressing the problem of wastewater and industrial effluent depollution. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Nanoparticle synthesis has seen exponential development recently as its characteristics of high surface area, high rate of adsorption, and easy, cost-effective synthesis have been exploited for the purpose of ground water purification via the removal of organic and inorganic compounds, along with the removal of heavy metals and microbes. The synthesis of Zero-Valent Iron Nanoparticles (ZVI NPs) by green methods has proved to be environmentally friendly in many ways as it employs the use of naturally occurring plant extracts. These nanoparticles have large surface areas and efficiently remove heavy metals. The reducing potential of these ZVI NPs is mostly −0.44 V, thus allowing them to reduce heavy metal compounds such as cadmium, lead, zinc, copper, and arsenic present in wastewater. Irradiated nanoparticles have also exhibited antimicrobial resistance and adsorption. It is also observed that nanoparticles show a higher rate of efficacy at a lower pH. The adsorbent, which is ZVI NPs in this case, when present in large doses reduces heavy metal compounds rapidly and effectively. [ABSTRACT FROM AUTHOR]

Removal of heavy metal ions such as cadmium, lead, chromium, and iron from industrial wastewater is one of the most critical environmental problems. In this research, natural and low-cost adsorbents like the tangerine peel, bovine gut, tea waste, and sunflower seed hull were used for adsorption of heavy metals, such as chromium and iron, from contaminated solutions. The effects of environmental factors such as contact time, pH, the amount of adsorbent dose, and the initial concentration of metal ions in synthetic solution were investigated to obtain optimal conditions for the adsorption of heavy metal ions. For separation of chromium metal ion from aqueous solution, tea waste, tangerine peel, bovine gut, and sunflower seeds hull showed adsorption capacity of 85%, 51%, 46%, and 34%, respectively, while for the adsorption of iron (III), the adsorption capacities of tea waste, bovine gut, tangerine peel, and sunflower seeds hull were 96%, 96%, and 87%, respectively. The adsorption isotherms were in decent correlation with the Langmuir and Freundlich isotherm models. The adsorption kinetics of iron and chromium has a proper validation with the pseudo-second-order kinetic model. The BET and FTIR analyses were also reported to investigate the adsorption properties. This study suggests these adsorbents as low-cost and economical materials for the adsorption of chromium and iron ions with a high adsorption rate. [ABSTRACT FROM AUTHOR]