The Removal of aclonifen from water by adsorption using carbon nanotubes

Yılmaz, Pelin
Aclonifen has adverse human and environmental effect at high concentrations. Conventional treatment may be insufficient for aclonifen treatment and may cause toxic effects on the living organisms. Therefore, removal of Aclonifen from wastewater is important in terms of ensuring surface water quality and preventing harmful effects. Adsorption, which is one of the advanced treatment methods, is generally applied by using activated carbon. However, recently adsorption with carbon nanotubes (CNT) is attracted great interest. In the removal of various inorganic and organic pollutants from water, the superior adsorption ability of carbon nanotubes is remarkable when compared with activated carbon. In this study, the aim was to investigate removal of aclonifen from wastewater by adsorption process with carbon nanotubes. Based on the monitoring results of TÜBİTAK project (115Y013) “Management of Point and Diffuse Pollutants Sources in Yeşilırmak River Basin” aclonifen was observed to exceed to Environmental Quality Standards (EQS) in early sampling seasons. Aclonifen is also in the new priority substance list that was recently revised (2013/39/EU). Thus, aclonifen was selected as model pollutant. To investigate effectiveness of different adsorbent aclonifen removal, laboratory scale batch experiments were carried out. In the equilibrium studies, different aclonifen/adsorbent ratios were used. Throughout this work, isotherm and kinetic model studies were performed, effects of pH, sonication and water matrix were studied. As a result of equilibrium studies, COOH functionalized CNT was chosen as the best adsorbent for the removal of aclonifen. Maximum removal was observed at the 1/100 aclonifen/adsorbent ratio. The removal efficiencies for aclonifen observed as 96%, 96%, 96%, 95% and 92% for COOH CNT, MWCNT, PAC, OH CNT and SWCNT respectively. It was observed that pH and temperature of the solution do not affect the adsorption of aclonifen by CNTs. Moreover, sonication of the CNT suspensions significantly accelerated the COOH CNT.