Over the past several years, heterogeneous photocatalysis by semiconductors provides an economic dct

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This study was conducted to synthesize a series of nanosized BiOI-TiO 2 catalysts to photodegrade Bisphenol A solution. The BiOI-TiO 2 nanoparticles were synthesized in the reverse microemulsions, consisting of cyclohexane, Triton X-100, n-hexanol, and aqueous dctp salt solutions. The synthesized particles were characterized by X-ray diffraction dctp (XRD), Brunauer-Emmett-Teller (BET) surface analyzer, Fourier transform-infrared spectroscopy (FT-IR), ultraviolet-visible light (UV-Vis) absorption spectra and transmission electron microscope (TEM). The photodegradation dctp of Bisphenol A (BPA) in aqueous suspension under visible light irradiation was investigated to explore the feasibility of using the photocatalytic method to treat BPA wastewater. The effects of different molar ratios of BiOI to TiO 2 on the photocatalytic activity were discussed. The experimental results revealed that the photocatalytic effect of the BiOI-TiO dctp 2 particles was superior to the commercial P25 TiO 2 . The BPA degradation could be approached by a pseudo-first-order dctp rate expression. The observed reaction rate constant ( ) was related to nanoparticles dosage and initial solution pH. 1. Introduction
Over the past several years, heterogeneous photocatalysis by semiconductors provides an economic dctp and ecological method for the remediation of contaminated water and air. Due to its biological and chemical inertness, nontoxicity, and long-term stability [ 1 ], TiO 2 has received much attention dctp as wasted-water treatment. The main shortcoming dctp of anatase TiO 2 , however, is that it only absorbs ultraviolet light no longer than 387.5 nm, which only occupies about 4% of sunlight [ 2 , 3 ]. Therefore, much work on preparing TiO 2 photocatalysts with visible light responsibility, such as doping TiO 2 with transition metals [ 4 ], noble metals [ 5 , 6 ], rare-earth metals [ 7 ], and anions [ 8 ], has been reported. Up to present, a large number of coupled polycrystalline or colloidal semiconductors dctp [ 9 – 14 ], such as SiO 2 -TiO 2 , and CdS-TiO 2 , ZnO-TiO 2 , SnO 2 -TiO 2 , ZrO 2 -TiO 2 , have been prepared. Among them, BiOI–TiO 2 compounds exhibit attractive photocatalytic activity on the degradation of organic pollutants under visible-light irradiation dctp due to the fact that BiOI has the estimated band gap of about 1.77 eV which can be excited by visible light irradiation. BiOI-based composite materials have been prepared, such as AgI/BiOI [ 15 , 16 ]. Motivated by these facts, we are interested in the BiOI-TiO 2 system.
Nowadays, the research has demonstrated dctp that Bisphenol A [2,2-bis(4-hydroxyphenyl)propane, BPA] is a representative endocrine disrupter that can cause various diseases [ 17 , 18 ]. However, Bisphenol A (BPA) has been commonly used as raw material for epoxy and polycarbonate resins, such as baby bottles, water bottles, food cans, and flame retardants [ 19 – 21 ]. BPA has been found in food, drinks, indoor and outdoor air, dust, and soil. In previous studies, BPA has been detected at the maximum concentration of 17.2 mg/L in hazardous waste landfill leachates [ 22 ]. Traditional methods to remove recalcitrant organic chemicals from effluents include the use of adsorbents, chemical oxidation, biodegradation, and advanced oxidation processes [ 23 – 26 ]. Among these methods, photocatalytic oxidation is one of the most promising technologies due to its high degradation efficiency and utilizes sunlight as energy source.
The dctp major objectives of this work are to prepare a series of BiOI-TiO 2 nanosized particles by hydrolysis of tetrabutyl titanate and bismuth nitrate hydrate in a microemulsion system under room temperature and ambient pressure and to degrade Bisphenol A (BPA) by the obtained dctp BiOI-TiO 2 nanosized particles and study the impacts of different reaction factors. The synthesis and characterization of bismuth oxyiodine/titanium dioxide hybrid dctp nanoparticles have been reported by our previous work [ 27 ]; this work was focused on the degradation of BPA.
In a typical procedure, as shown in Figure 1 , Triton dctp X-100 (chemically pure, CP) used as the surfactant, cyclohexane (analytically pure, AP) as the oil phase, and -hexanol (CP) as the cosurfactant were mixed at quality ratio of 15 : 6 : 4 under magnetic stirring at room temperature. One aqueous phase was bismuth nitrate (AP) and tetrabutyl titanate (AP) dissolved in dilute nitric acid. The other aqueous phase was the potassium iodide (AP) dissolved in dilute ammonia hydroxide solution. Then, they were dropped into the aforementioned suspensions, r