Highly efficient removal of thallium(I) by facilely fabricated amorphous titanium dioxide from water and wastewater

Abstract

In this study, amorphous hydrous titanium dioxide was synthesized by a facile precipitation method at room temperature, aiming to effectively remove thallium(I) from water. The titanium dioxide prepared using ammonia as precipitant (TiO2I) is more effective for thallium(I) uptake than the one synthesized with sodium hydroxide (TiO2II). The TiO2 obtained particles are amorphous, aggregates of many nanoparticles and irregular in shape. The thallium(I) uptake increases with the rise of solution pH value. Under neutral pH conditions, the maximal thallium(I) adsorption capacities of TiO2I and TiO2II are 302.6 and 230.3 mg/g, respectively, outperforming most of the reported adsorbents. The amorphous TiO2 has high selectivity towards thallium(I) in the presence of multiple cations such as K+, Ca2+, Mg2+, Zn2+ and Ni2+. Moreover, the TiO2I is efficient in removing thallium(I) from real river water and mining wastewater. Additionally, the spent TiO2I can be regenerated using hydrochloric acid solution and reused. The Tl(I) adsorption is achieved via replacing the H+ in hydroxyl group on the surface of TiO2 and forming inner-sphere surface complexes. Owing to its high efficiency, facile synthesis and environmental friendliness, the TiO2I has the potential to be used as an alternative adsorbent to remove Tl(I) from water.

Removal of Thallium from Aqueous Solutions by Adsorption onto Alumina Nanoparticles

“…Its acute toxicity to humans brings about vomiting, diarrhea, temporary loss of hair; affects the nervous system, lungs, heart, liver, and kidneys; and can even lead to death [9]. Epidemiological data showed that exposure to Tl during pregnancy may also have negative effects on birth outcomes, such as fetal death, congenital malformations, or decreased birth weight [10,11]. An exposure to Tl concentration levels in the range of 0.1 to 100 µg/L may be considered chronic [12][13][14].…”

“…To date, few studies have reported adsorption behavior and removal efficiency of thallium (I) at low concentration. As a matter of fact, most of the investigations were carried out at high thallium (I) concentration ranging from 1-150 mg.L −1 , whereas thallium is found to be in the range of a few µg.L −1 in real polluted water sources [11,16,28]. In this paper, the removal of Tl(I) ions at low concentration, through adsorption onto synthesized gamma-alumina nanoparticles, was investigated for the first time.…”