water. [1] Furthermore, looking into the future, increasing amounts of fresh water will be required to account for population growth, greenhouse gas induced climate change, contamination of freshwater resources, industrial expansion, and agricultural activities. It has been reported that the only methods capable of meeting the increasing demands for freshwater supply are desalination and water reuse. [2] Of these, seawater and brackish water desalination offers a seemingly unlimited and high-quality water supply since 71% of the planet's surface is covered by ocean. Presently, two of the most successful commercialized technologies for water desalination are the multistage flash (MSF) distillation and reverse osmosis (RO) processes. [3] The MSF process is being gradually replaced by the RO process since it produces large quantities of fresh water while consuming less electric energy and having a smaller CO 2 footprint. [4] In the past two decades, numerous large-scale seawater desalination plants based on the RO processes have been built worldwide to harvest available water resources, and the global water production by desalination is projected to exceed 38 billion m 3 per year in 2016. [5] Compared to conventional drinking water treatment processes (coagulation, sedimentation, filtration, and disinfection), seawater desalination consumes a greater amount of electric energy, and thus emits a larger quantity of greenhouse gases. [4] Moreover, a large number of marine organisms, especially juvenile-stage fish, are killed during the seawater intake process. [6] In addition, electric power and centralized water desalination maybe unavailable for the RO process in some remote and rural areas.To overcome these two disadvantages of the RO process, a new concept, named "Air-Water Interface Solar Heating" (AWISH), has been employed for seawater desalination by modifying the old "Solar Distillation Seawater Desalination" (SDSD) process. [7,8] In this conceptually new process, black materials that are capable of efficiently absorbing the solar irradiance and converting it to heat energy are coated on meshes, gauzes or other floating supports. To date, black materials that have been investigated to function as solar-thermal absorbers in AWISH desalination apparatuses include Fe 3 O 4 /C, [8] carbon nanoparticles, [9] black gold, [10] polypyrrole, [7] aluminum nanoparticles, [11] hollow TiO x (x < 2) nanoparticles with tunable colors from white to gray to bluegray to black are synthesized by magnesium (Mg) reduction of white P25 TiO 2 nanocrystals followed by removal of excess Mg with aqueous HCl and distilled water. Increasing amounts of Mg smoothly decrease the oxygen content in TiO x which is responsible for the gradual increase in light absorption and concomitant darkening of its color from white to black with decreasing values of x. The as-synthesized TiO x nanoparticles are spin-coated onto the surface of a stainless steel mesh followed by surface superhydrophobization in order to test their performance as a solar water...

Hydrophobic magnetic microspheres can self-assemble into a thin film and float on the surface of water. The formed film was used as a photothermal material for water evaporation based on a new concept of interfacial solar heating.

BiOCl microspheres with exposed {001} facets have been synthesized through a simple solvothermal method. The adsorption and photocatalytic activities of BiOCl microspheres were evaluated by removal of ibuprofen (IBP) as the model reaction. Parameters including IBP concentration, BiOCl dosage, and inorganic ions were investigated to reveal the role of adsorption in BiOCl-based photocatalysis. We found that the high IBP removal rate by BiOCl is not due to photocatalytic oxidation but to surface adsorption. The combination of ICP/MS, IC, XPS, and FT-IR results directly proved that anion exchange between dissociated IBP and Cl accompanied by the formation of surface complex (O-Bi-OOC-CH) onto the BiOCl surface is the main adsorption mechanism. In addition, we also demonstrated that organic compounds with carboxyl group (-COOH) such as diclofenac, benzoic acid, and p-phthalic acid can be adsorbed by BiOCl while organic compounds without carboxyl group such as carbamazepine, nitrobenzene, and p-chloronitrobenzene cannot be adsorbed. We believe that the BiOCl adsorption behavior and mechanism should be considered when discussing its photocatalytic mechanism.

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