Efficient selenium(IV) detection and removal from water by tailor-made novel conjugate adsorbent

Abstract

Selenium occurs naturally in the environment and is toxic at elevated concentrations, which has been a challenging issue for environmental scientists. This work was devoted to the detection and removal the selenium (Se(IV)) from aqueous solutions using organic ligand an immobilized conjugate adsorbent. The organic ligand of (3-(3-(methoxycarbonyl) benzylidene)hydrazinyl) benzoic acid was synthesized and indirectly immobilized onto the mesoporous silica. The adsorbent was applied to detect and remove Se(IV) in aqueous solutions at optimum conditions. This adsorbent exhibited high surface area-to-volume ratios and pores were uniform nanostructures. The adsorbent permitted rapid Se(IV) capturing detectable by naked eye observation. The limit of detection was 2.02μg/L by the proposed method of the conjugate adsorbent. The Se(IV) capture system was optimized by varying the parameters of contact time, pH, initial concentration, competing ions and elution operations. The pH effect played an important role and the solution pH ranging from 0.5 to 7.0 was investigated. The data confirmed that acidic pH enhanced the Se(IV) sorption on the conjugate adsorbent resulting in an increased sorption efficiency percentage of Se(IV) to >98% at pH 1.50. The data were also fitted to the Langmuir isotherm, and the maximum sorption capacity was 93.56mg/g. The introduction of diverse ions was individually added to solution, and these had no significant effect on the Se(IV) sorption by the adsorbent. The 0.20M NaOH was used an eluent in the elution operation, and the adsorbent was used in many cycles without loss of cage cavities. Therefore, the conjugate adsorbent has shown favorable capturing ability in water samples, and this could be used as efficient adsorbents in potential practical applications for Se(IV) detection and removal from wastewater.