Simultaneous removal of Cong red and Cr (VI) in aqueous solution by using Mn powder extracted from battery waste solution

Adsorption capacity of manganese powder synthesized from spent battery waste solution was analyzed for simultaneous removal of congo red and hexavalent chromium. Manganese powder was synthesized by heat treatment followed by reaction with sodium borohydride to spent lithium-ion batteries. The removal conditions viz., pH, dosage of manganese and various concentrations of congo red and hexavalent chromium were optimized. The synthesized manganese powder was characterized by X-ray fluorescence spectrometer (XRF), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Further, FESEM was done to observe the difference in surface morphology of the particles with and without treatment. The adsorption performance was studied and the highest adsorption by the zero manganese was 475 mg/g and 125 mg/g for CR and Cr (VI), respectively when different concentrations of the contaminants (400 mg/L CR and 100 mg/L Cr (VI)) was used. Under the optimum conditions, simultaneous removal from 450 mg/L of CR to 250 mg/L and 125 mg/L of Cr (VI) to around 74 mg/L was achieved. Desorption study of the treated zero manganese exhibited that acid treatment (0.1 M HCl) for CR and alkali treatment (0.1 M NaOH) for Cr (VI) as the suitable reagent for desorption.