Use of cellulose acetate–tin (lV) phosphate composite (CA/TPC) in highly effective removal and recovery of heavy metal ions

摘要

A novel cellulose acetate–tin (IV) phosphate composite material has been synthesized under varying conditions. The material was characterized by FTIR, SEM, EDX and XRD. The composite material was explored for its use in separation of toxic metal cations present in electroplating waste discharge and similar synthetic fluid by varying the system conditions [temperature (298–313?K), pH (2–12), time (10–420?min), dosage (1–10?g) and initial concentration of metal cations (1.0–15.0?mg/dm3)]. Highest removal rate was achieved for Cr3+, Ni2+ and Zn2+ (99, 98 and 94?%) under optimal conditions. Experimental equilibrium data for Cr3+, Ni2+ and Zn2+ ions fitted well with Langmuir isotherms (R2?>?0.99). The adsorption capacities for Cr3+, Ni2+ and Zn2+ ions were found to be 31.5, 43.7 and 43.4?mg/g. Pseudo-second-order model explained the kinetics of adsorption (R2?>?0.99) for all the metal ions undertaken in the study. Thermodynamic parameters such as ΔG, ΔS and ΔH show spontaneity and endothermic nature of the process at all the concentration ranges studied (2–15?mg/dm3). Desorption of metal ion from (CA/TPC) surface was carried out using 0.1?N nitric acid as an eluent under varying system pHs (1–6). Maximum desorption’s for all the metal ions were observed at pH 1. The adsorption efficiencies of CA/TPC for the metal ions were maintained after four consecutive cycles of adsorption/desorption process. The loss in the dry weight of CA/TPC was not more than 10?% after each cycle of process. Due to easy and high regeneration properties of CA/TPC, it was found to be economical and have shown potential benefits in recovery of metal ions from wastewater.