Arsenic Uptake From Artisanal Gold Mining Wastewater Using Magnetized and Functionalized 2‐Mercaptobenzothiazole Nanosilica: Characterization, Taguchi Optimization, Statistical Analysis and Adsorbent Reusability
Lekan Taofeek Popoola, Nacer Badi, Usman Taura, Yuli Panca Asmara, Alfred Ogbodo Agbo, Celestine Chidi Nwogbu, Tajudeen Adejare Aderibigbe, Saheed Olalekan Alawode, Lois Onyejere NwobodoABSTRACT
Arsenic is a naturally occurring pathfinder element in gold mineralization, making its release into process effluents unavoidable. This study evaluates advanced wastewater treatment methodology to selectively remove and immobilize arsenic. Effective decontamination is imperative to mitigate the health risks associated with exposure to highly toxic, carcinogenic metallurgical byproducts, ensuring regulatory compliance, and safeguarding public health. This study applied nanosilica from rice husk, magnetized and functionalized with FeSO 4 /FeCl 3 and 2‐mercaptobenzothiazole, respectively, (MFMBTnS) to remove As 5+ from local gold mining wastewater (GMW). The removal efficiency of MFMBTnS was investigated via checking the effect of reaction time, dosage, temperature, and mixing rate on batch adsorption of As 5+ from GMW using Taguchi Orthogonal Array. Adsorbent was characterized via XRD, SEM, FTIR, BET, and evaluation of saturation magnetization. MFMBTnS removed 98.97% ± 1.26% of As 5+ from GMW at optimum predicted point (where t = 90 min, D = 3 g, T = 50°C and M = 130 rpm). ANOVA test revealed R 2 , F ‐value and p ‐value of 0.9967, 13.01, and 0.0316, respectively suggesting high significance of the model. MFMBTnS was suitable for the adsorption process. After five cycles of reusability, MFMBTnS was able to remove 92.73% ± 1.23% of As 5+ from GMW. MFMBTnS is a low cost adsorbent having a production cost of $13.2/kg of raw rice husk processed.