Valorization of walnut husks as a natural coagulant for optimized water decolorization

Abstract

Coagulation-flocculation is an essential wastewater treatment and decolorization process. This study investigates walnut husks, an abundant agricultural waste, as a biocoagulant. The aim is to evaluate the coagulation efficacy of walnut husk powder (WHP) for removing methylene blue (MB) and turbidity (TUR) from water. WHP was prepared and characterized using Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM-EDX), and X-ray fluorescence spectrometry (XRF) techniques. Jar tests were conducted in varying doses, granulation, and the initial pH. Box Behnken Design based on the response surface method (BBD-RSM). Predicted MB and TUR eliminations matched experimental values. Under optimal conditions at pH 9, 89.48 % MB and 96.59 % TUR removal were attained at 900 mg. L-1 and 1000 mg. L-1 doses. Results prove that WHP shows promise as an efficient biocoagulant for the removal of dyes and turbidity from wastewater.