Utilization of a newly developed nanomaterial based on loading of biochar with hematite for the removal of cadmium ions from aqueous media

Abstract

In order to conserve the energy used for remediation of harmful metals from aqueous media, an adsorption process was performed. It is efficient and low-cost method with zero carbon emissions as compared to other methods. A hematite-based novel nanomaterial loaded onto biochar was utilized for the remediation of toxic cadmium metal ions from aqueous media. Saccharum munja has been employed as low-cost feedstock to prepare the biochar. Three adsorbents i.e., raw Saccharum munja (SM), Saccharum munja biochar (SMBC) and hematite-loaded Saccharum munja bichar (HLSMBC) were used in batch adsorption tests to study uptake of metal ions by optimizing the experimental parameters. Experimental data and calculated results revealed maximum sorption efficiency of Cd(II) removal was given by HLSMBC (72 ppm) and SMBC (67.73 ppm) as compared with SM (48.7 ppm). Among adsorption isotherms applied on work best fit for Cd(II) adsorption on SM was found for a Freundlich isotherm with high values of correlation coefficient R2 ≥ 0.9 for all sorbents and constant 1/n values between 0–1. Equilibrium results were evaluated using five different types of errors functions. Thermodynamic studies suggested feasible, spontaneous and endothermic nature of adsorption process, while, the ∆H parameter < 80 kJ/mol indicated physiosorption and positive ∆S values promoted randomness of ions with increase in adsorption process. Data fitted into type I of pseudo second order kinetics having R2 ≥ 0.98 and rate constants K2 (0–1). Desorption process was also performed for storage, conservation and reuse of sorbent and sorbate materials.