Organics adsorption on novel amorphous silica and silica xerogels: microcolumn rapid breakthrough test coupled with sequential injection analysis

The adsorption capacities of a novel amorphous silica and silica xerogels for aromatic compounds were investigated using microcolumn rapid breakthrough tests coupled with sequential injection flow-based automated instrumentation in order to evaluate their operative feasibility under conditions typically used in water treatment facilities. Extraction columns were fabricated using stereolithographic 3D printing. Sorbent reusability was also investigated using automated flow-based techniques. Benzene was selected as the target dissolved organic compound usually present in produced waters from the oil and gas sector, continuously increasing. 3,4-Dichloroaniline (3,4-DCA) was selected as part of the endocrine disrupting chemicals, which are becoming a source of major concern for human and wildlife toxicity. Novel amorphous silicas were synthesized at low temperature and under ambient pressure from a sodium metasilicate precursor and were subjected to postsynthetic methylation. Silica xerogels were prepared via acid catalysis of a sodium metasilicate solution and functionalized with trimethylchlorosilane at low temperature and under ambient pressure. The removal efficiency of the silica xerogels tested was found to be equal to or greater than 22.62 mg/g for benzene at a flow rate of 0.6 mL/min, while the uptake of 3,4-DCA was found to be > 4.63 and > 7.17 mg/g, respectively, at flow rates of 1.8 and 0.6 mL/min.