Application of RSM for Bioremoval of Methylene Blue Dye from Industrial Wastewater onto Sustainable Walnut Shell (Juglans regia) Biomass

Abstract

Dyes are a significant group of organic contaminants known to negatively affect both humans and aquatic environments. In the textile industry, interest in agricultural-based adsorbents has increased, particularly around adsorption. In this study, methylene blue was eliminated from an aqueous solution using a walnut (Juglans regia) shell. These materials are widely available and inexpensive, and its cost can be a major factor in wastewater treatment batch experiments. Response surface methodology (RSM) is based on a face-centred central composite design, used to identify the independent variable. With the use of RSM, the biomass of J. regia shells was assessed for its capacity to absorb dyes from aqueous solutions, including methylene blue. Maximum methylene blue dye removal percentages (97.70%) were obtained with a 30 mg/L concentration of methylene blue dye, 1.5 gm of biomass, an initial pH of 6, and a contact duration of 60 min at 25 °C. Additionally, particles were absorbed onto the J. regia shell’s surface throughout the biosorption process, according to scan electron microscopy. Functional groups were discovered in the Fourier Transform Infrared Spectroscopy spectra, which are crucial for binding during the biosorption of methylene blue. It has been demonstrated that J. regia shell biomass performs well as a biosorbent in the removal of methylene blue from wastewater effluents. It is also a promising, biodegradable, environmentally friendly, economical, and cost-effective biosorbent.