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SUMMARY Hydrogen generation by the reaction of pure Al powder in water with the addition of Al(OH)3, γ‐Al2O3, α‐Al2O3, or TiO2 at mild temperatures was investigated. It was found that the reaction of Al with water is promoted and the reaction induction time decreases greatly by the above hydroxide and oxides. X‐ray diffraction analyses revealed that the hydroxide and oxide phases have no any change during the Al–water reaction, indicating that they are just as catalysts to assist the reaction of Al with water. A possible mechanism was proposed, which shows that hydroxide and oxides could dissociate water molecules and promote the hydration of the passive oxide film on Al particle surfaces. Copyright © 2013 John Wiley & Sons, Ltd.

Different Al(OH) 3 powders were used as adsorbents for fluoride removal from water. The results showed that the defluoridation performance of ultrasonically prepared Al(OH) 3 (UAH) is much better than that of commercially available Al(OH) 3 and is comparable to that of activated alumina, because the ultrasonic waves effectively break the agglomerates in the suspension so that the UAH particles are fine and have a beneficial phase constituent. Furthermore, the residual aluminum concentration in aqueous solution after defluoridation by Al(OH) 3 was found to be one order of magnitude lower than that obtained with activated alumina which is below the World Health Organization (WHO) guideline for aluminum (0.2 mg L À1 ) in drinking water. The defluoridation dynamics and mechanism for UAH are discussed in detail.

Fe-based metal-organic framework MIL-88A microrods were synthesized by hydrothermal method, which were used to adsorb As(V) in water for the first time. The experimental results indicated that MIL-88A has a very fast adsorption rate towards arsenic in water. The kinetic and isothermal data for arsenic removal were better fitted to the pseudo-second-order kinetic model and Langmuir model, respectively, implying a chemical and monolayer adsorption for As(V) on MIL-88A microrods. Two rate-controlling processes during adsorption were revealed by the intraparticle diffusion model. The maximum adsorption capacity of MIL-88A reached 145 mg g, higher than those of Fe-based MIL adsorbents reported previously, which probably originates from its unique microstructure with abundant OH groups and an unusual large swelling towards water. These show that Fe-based MIL-88A is a good candidate for arsenic removal.

Excessive intake of fluoride can lead to a series of fluorosis based diseases, and how to remove the excess fluoride from water is an urgent issue worldwide. Among various defluoridation...