Improvement in performance of sludge-based adsorbents by controlling key parameters by activation/modification: A critical review (original) (raw)
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Water Science & Technology, 2006
With an objective of production of carbonaceous sorbent for industrial effluent treatment, physical activation by steam of biological sludge collected from the municipal wastewater treatment plant of Nantes (France) was studied and optimised using experimental design. Thus, this activation process consists of a carbonisation under N2 atmosphere at 600 °C for 1 h, followed by a thermal oxidation using steam (760 °C, 0.5 h, 2.5 L/min). The global mass yield of the process is equal to 38%. The thermal treatment allows a specific surface area of up to 225 m2/g to be reached, the porous structure being composed of both micropores and mesopores. The content of acidic surface groups is 0.71 mEq/g whereas that of basic surface groups is 0.55 mEq/g. The adsorption properties of the sorbent made from sludge are estimated with regard to various pollutants representative of industrial pollution of wastewaters and compared with those of commercial activated carbon. Whereas the adsorption capacit...
Development of sustainable adsorbents for wastewater treatment
2016
The purpose of this study was to develop adsorbents from slag materials as a low cost method to purify acid mine drainage of high acidity and toxic metal ions content. The study included adsorbent characterisation and adsorption experiments to understand the adsorption behaviour of a multi-adsorbate system of Cd\(^2\)\(^+\), Co\(^2\)\(^+\), Cu\(^2\)\(^+\), Fe\(^2\)\(^+\) and Mn\(^2\)\(^+\) ions. It was found that the adsorbents had low surface area and unfavourable pore size distribution. The chemical activation of the adsorbents improved the adsorbent properties, and thus increased amounts of metal ions adsorbed. However, the adsorption of multiple metal ions was only effective in dilute solutions, with adsorption efficiency increasing with increase in phase ratio, pH and temperature. The adsorption data was best described by pseudo second order kinetic and double exponential diffusion models. The mechanisms involved adsorption, precipitation and ion exchange. The adsorbent capacit...