An efficient and magnetic adsorbent prepared in a dry process with enzymatic hydrolysis residues for wastewater treatment

Abstract

A clean and facile dry process was developed for the preparation of a novel magnetic absorbent by directly ball milling of enzymatic hydrolysis residues (EHRs) and Fe3O4 nanoparticles together. Different from the typical liquid processes, the dry-preparation of absorbent could get rid of the use of chemical reagents and the treatment of spent liquor, and thus simultaneously improve the preparation effect. It was demonstrated that the Fe3O4 nanoparticles not only endowed the absorbent with magnetic property, but also acted as a puncher to significantly increase the specific surface area of the obtained Fe3O4@EHRs adsorbent. Benefiting from these two advantages, the adsorption capacity of the as-prepared adsorbent was improved efficiently. Results indicated that the as-prepared Fe3O4@EHRs adsorbent exhibited high adsorption capacity for various adsorbates. The highest adsorption capacities obtained at equilibrium stage for Methylene blue, Congo red, and Cr (VI) were 562.17 mg/g, 587.94 mg/g, and 31.41 mg/g, respectively. Therefore, this study presents a facile and sustainable approach for the preparation of highly efficient adsorbent with the advantages of high adsorption capacity, inexpensive cost, and magnetic collectability, which have great practical potential for wastewater treatments.