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A novel technique for photocatalytic removal of elemental mercury (Hg 0 ) using visible-light-driven Ag/AgBr-Ag 2 CO 3 hybrids was proposed. The ternary Ag/AgBr-Ag 2 CO 3 hybrids were synthesized by a simple modified co-precipitation method and characterized by N 2 adsorption-desorption, scanning electron microscope (SEM), X-ray diffraction (XRD), UV–vis diffused reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) techniques. The effects of AgBr content, fluorescent lamp (FSL) irradiation, solution temperature, SO 2 and NO on Hg 0 removal were investigated in detail. Furthermore, a possible reaction mechanism for higher Hg 0 removal was proposed, and the simultaneous removal of Hg 0 , SO 2 and NO was studied. The results showed that a high efficiency of Hg 0 removal was obtained by using Ag/AgBr-Ag 2 CO 3 hybrids under fluorescent lamp irradiation. The AgBr content, FSL irradiation, solution temperature, and SO 2 all exhibited significant effects on Hg 0 removal, while NO had slight effect on Hg 0 removal. The addition of Ca(OH) 2 demonstrated a little impact on Hg 0 removal and could significantly improve the SO 2 -resistance performance of Ag/AgBr(0.7)-Ag 2 CO 3 hybrid. The characterization results exhibited that hydroxyl radical ( OH), superoxide radical ( O 2 − ), hole (h + ), and Br 0 , were reactive species responsible for removing Hg 0 , and the h + played a key role in Hg 0 removal. [ABSTRACT FROM AUTHOR]

Abstract: In order to remove perchlorate from water via adsorption, three modified inorganic-bentonites, such as hydroxy-aluminum pillared bentonite (Al-Bent), hydroxy-iron pillared bentonite (Fe-Bent), and mixed hydroxy-iron–aluminum pillared bentonite (Fe–Al-Bent), were synthesized and characterized. Bench-scale batch experiments were performed to study mechanisms behind the adsorption phenomenon and explore the factors affecting the perchlorate adsorption on pillared bentonites. The significant increase of interlayer spacing, BET surface area and total pore volume suggested a larger amount of active adsorption sites of the pillared bentonites surface and a wider perchlorate channel from the surface to the inner adsorption sites of bentonites, respectively. The results during adsorption process represented that the adsorption capacity of perchlorate followed the order: Fe-Bent>Fe–Al-Bent>Al-Bent. The perchlorate uptake on these three modified bentonites from 0.1mmol/L solution rapidly attained equilibrium within 100min. Pseudo-second-order kinetic model could provide satisfactory fitting of the kinetic data (R 2 >0.99). The Langmuir model fitted the adsorption isotherm very well (R 2 >0.98). The thermodynamic analysis indicated that the adsorption process was endothermic and spontaneous in nature. The pH changes appeared to have a little impact on the perchlorate adsorption performance using the Fe-Bent. While perchlorate removal by Al-Bent and Fe–Al-Bent decreased significantly with the increase of pH. Co-existing anions tests showed that the order of anion influence of the adsorption amount of on pillared bentonite was . The present study confirmed that inorganic-pillared bentonites would be one of candidates for perchlorate adsorbent. [Copyright &y& Elsevier]