Arabian Journal of Chemistry (Sep 2024)
Optimizing coolant oil wastewater treatment via modified air-Fenton process with bimetallic particles from auto parts manufacturing waste
Abstract
This study evaluated the efficiency of aluminium (Al)/iron (Fe) bimetallic particles, produced from waste by-products of auto parts manufacturing—namely, aluminum dross (AD) and shot blast (SB)—in removing chemical oxygen demand (COD) and total organic carbon (TOC) from coolant oil wastewater originating from an auto parts manufacturer. Two different molar ratios of ADSB bimetallic particles, namely, 1:1 (ADSB1) and 2:1 (ADSB2), were investigated for their characteristics and applied in the modified air-Fenton (MAF) process which enhances the traditional Fenton method by utilizing ADSB bimetallic particles instead of Fe0 and Al0, and by incorporating aeration to stimulate the reaction. The wastewater contained an initial COD ranging from 60,000 to 120,000 mg L–1 (at 3–5 % v/v) and a TOC ranging from 10,000 to 40,000 mg L−1. The experimental design included varying reaction times, pH values, quantities of bimetallic particles, airflow rates, and wastewater concentrations were performed using the Minitab-19 software package. X-ray fluorescence (XRF) analysis revealed that the bimetallic particles have SiO2 content ranging from 39.69 % to 56.03 %, Fe2O3 ranging from 20.52 % to 30.90 % and Al2O3 ranging from 16.51 % to 16.66 %, with surface areas varying between 5 and 6 m2 g−1. As a result of XRF analysis, SiO2 can be contaminated by the sand molds used in the manufacturing process of products. Notably, ADSB1 exhibited impressive removal efficiencies of 98.70 % and 98.50 % for COD and TOC, respectively, at 0.6 g, pH 3, airflow rate of 1.5 L min–1, and reaction time of 105 min. Conversely, ADSB2 achieved removal efficiencies of 96.30 % and 98.43 % for COD and TOC, respectively, at 0.2 g, pH 9, airflow rate of 2.0 L min–1, and reaction time of 180 min. Pareto charts and 3D surface plots derived from the data showed the number of bimetallic particles as the most influential factor, followed by the initial pH. The MAF process significantly extends the pH range under diverse conditions by incorporating ADSB particles and reduces the reliance on traditional chemicals like hydrogen peroxide. This research presents a promising advancement in wastewater treatment technology.
