SD/MnFe2O4 composite, a biosorbent for As(III) and As(V) removal from wastewater: Optimization and isotherm study

The present study proposed the mechanism of elimination of As(III) and As(V) from synthetically wastewater using SD/MnFe2O4 composite (MSD). A variety of techniques were utilized to characterize the structure, morphology of the composite. Influences of different parameters, like pH, biosorbent dose, contact time, temperature and initial arsenic concentration on the As(III) and As(V) biosorption were studied thoroughly to evaluate optimum condition. Initial As(III) and As(V) concentration influenced the removal efficiency of SD/MnFe2O4 composite. At optimum conditions, the elimination of As(III) and As(V) ions was 86.95% at pH 7.0 and 89.69% at pH 4.0, respectively. Non-linear regression analysis was carried out for identifying the best-fit isotherm based on three correlation coefficients and three error functions and also to predict the parameters involved in the one one-parameter, six two-parameter, nineteen three-parameter, three four-parameter and one five-parameter isotherms by OriginPro (8.5.1 version) software. The mean adsorption energy (E) evaluated from D-R model indicated the nature of adsorption being ion exchange type. Desorption study exhibited that over 79% of As(III) and 81% of As(V) could be desorbed from composite with 0.05 M NaOH solution. Effects of co-existing ions present in copper smelting wastewater were examined.