Arsenic Adsorption by TiO 2 Nanoparticles Under Conditions Similar to Groundwater: Batch and Column Studies
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RESEARCH PAPER
Arsenic Adsorption by TiO2 Nanoparticles Under Conditions Similar to Groundwater: Batch and Column Studies Atieh Nazari1 · Mohammad Nakhaei1 · Ahmad Reza Yari2 Received: 8 December 2019 / Revised: 17 October 2020 / Accepted: 28 October 2020 © University of Tehran 2020
Abstract Nano-sized TiO2 particles containing anatase and rutile were applied to arsenic removal from water in natural groundwater conditions in the batch and column experiments. Arsenic concentrations were 200 µg L −1 and the pH range was 6–8.5 (similar to groundwater conditions). The results showed that anatase and rutile could adsorb 95.5% and 63.5% of arsenic in a solution after 60 min, respectively. In both adsorbents, arsenic adsorption was increased by increasing the adsorbent concentration. Increasing pH results increased adsorption in rutile more than anatase. The maximum adsorption capacity of 2.58 mg g−1 and 1.86 mg g−1 were calculated for anatase and rutile, respectively at the adsorbent concentration of 3 g L−1. Isotherm studies showed Freundlich model was more valid to the empirical adsorption data for both nanoparticles. The kinetics of the adsorption processes fitted well the pseudo-first-order adsorption model. To investigate the dynamic sorption, column study was carried out with fine and coarse silica sand porous media. According to the batch experiments, only anatase nanoparticles were injected into the column as an adsorbent at different doses. Breakthrough curves (BTC) showed the best efficiency of arsenic removal can be obtained by an adsorbent dose of 8 g L−1 in the fine sand column. Article Highlights • • • •
TiO2nanoparticles (anatase and rutile) could be the effective adsorbent for reducing arsenic content from water. The kinetic of the adsorption by rutile fitted well the pseudo-first-order adsorption model. Anatase nanoparticle is more efficient than the rutile for the arsenic removal in groundwater conditions. Anatase nanoparticle could be an instrumental agent for the in situ remediation in arsenic-contaminated aquifers.
Keywords TiO2 nanoparticles · Arsenic · Isotherm · Kinetic · Column studies
Introduction Natural water contaminations by heavy metals are important because of their toxicity for the human and environment (Al-Abdullah et al. 2018; Tang et al. 2016). Arsenic is a common toxic heavy metal contaminant and a high concentration of it has been reported in most parts of the world’s groundwater. Millions of people in the world are dependent * Atieh Nazari [email protected] 1
Departement of Applied Geology, Faculty of Earth Science, Kharazmi University, Tehran, Iran
Research Center for Environmental Pollutants, School of Health, Qom University of Medical Sciences, Qom, Iran
2
on groundwater for drinking water (Deedar and Aslam 2009; Erickson 2003; Jain and Loeppert 2000). Long-term drinking of water containing arsenic can cause changes in skin pigments and increase the risk of developing some cancers including liver, lungs, bladder and, kidney (Mujawar et al. 2018; Shaky
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