Efficient adsorption of heavy metals from wastewater on nanocomposite beads prepared by chitosan and paper sludge.

Chitosan was commonly used with inorganic salt and organic compounds to prepare adsorption material for water treatment. Different materials were mixed for the preparation, leading to a high cost for water treatment. Sludge from papermaking has abundant fiber and inorganic salt, which can reduce the addition of raw materials in preparing the adsorption material and thus lower the cost. This work used recycled industrial paper sludge to prepare adsorption material to remove heavy metals from wastewater. The adsorption properties of the prepared sludge-chitosan material for Cu ²⁺ and Cr ³⁺ in wastewater were investigated. The impacts of adsorption time, pH, and initial concentrations of Cu ²⁺ and Cr ³⁺ on adsorption amount were studied and optimized. The saturated adsorption capacity of sludge-chitosan material for Cu ²⁺ and Cr ³⁺ can reach 114.6 and 110.3 mg/g. The adsorption kinetics satisfied the pseudo-second-order model, indicating two modes, physical diffusion, and chem-sorption, in the heavy metal adsorption by the sludge-chitosan materials. Physical distribution has little Effect on chemical adsorption. The materials can be applied to treating Cu ²⁺ and Cr ³⁺ containing wastewater with the proposed cheap and readily available sludge-chitosan material. The results confirmed that sludge-chitosan material possessed good regeneration performance and was an ideal adsorbent.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work presented in this paper.
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