Photocatalytic Degradation of Organic Pollutants in Purified Terephthalic Acid Wastewater with Activated Carbon Supported Titanium Dioxide

Abstract

Activated carbon (AC) supported titanium dioxide (TiO 2 ) photocatalyst (TiO 2 /AC) was prepared by two-step solgel process. Crystal structure, and surface morphology of TiO 2 /AC were characterized by X-ray diffraction (XRD), N 2 adsorption-desorption isotherm measurements (BET) and scanning electron microscopy (SEM), respectively. The results show that average crystal size of TiO 2 in 11% TiO 2 /AC catalyst is 17.6 nm and special surface area of AC carrier is 887.11 m 2 /g. The photocatalyst has highly developed microporous structure, improves the dispersion degree of TiO 2 , and decreases the size of aggregate. Meanwhile, TiO 2 /AC was applied to degradate organic pollutants in purified terephthalic acid (PTA) wastewater.The obtained optimum conditions of photocatalytic degradation are as follows: the mass amount of TiO 2 loaded on AC is 11 %, the usage amount of catalyst is 7 g/ L wastewater and reaction time is 7 h. Under the optimum conditions, the COD removal ratio of wastewater is up to 64.30 %.Keywords-TiO 2 /AC catalyst; photocatalytic degradation; purified terephthalic acid wastewater . INTRODUCTIONIn the production of PTA, large amount of organic wastewater is produced, which contains high concentration of various organic pollutants with wide range of pH value. PTA wastewater must be treated before discharge. The organic pollutants with benzene ring structure in wastewater are stable, so they are difficult to biodegradate [1]. The traditional treatment process is complicated and expensive, and always causes secondary pollution [2]. Therefore, it is crucial to develop a new method to eliminate organic pollutants in PTA wastewater. The effective and economical method is focused on the non-biodegradable treatment process.The study on the degradation of poisonous polychlorinated biphenyls with TiO 2 was carried out by Carey in 1976 [3], which marked the beginning of application and research of TiO 2 photocatalyst. However, TiO 2 particles are too small, which causes difficulties of catalyst recovery.In order to resolve the problem of catalyst loss, researchers supported TiO 2 particles on solid carrier [4][5][6][7][8]. Carbon as carrier was used to support TiO 2 by Mozia[4], * Corresponding author. and the preparede TiO 2 /carbon catalyst was put into the methylene solution for decoloring treatment. The results showed that the catalyst not only had good decoloring effect, but also could be recovered and recycled well. Recently, heterogeneous photocatalysts TiO 2 /AC have been applied in the degradation of organic pollutants in the dyeing wastewater [5], pesticides wastewater [6] et al, but there is little literacture about photocatalytic degradation of organic pollutants in PTA wastewater with TiO 2 /AC catalyst. In this paper, TiO 2 /AC catalyst was prepared by two-step sol-gel process [9], and characterized by XRD, BET and SEM. Then, the catalyst was applied to degradate organic pollutants in PTA wastewater, and the degradation effection was investigated. II. EXPERIMENTAL A. Preparation of TiO 2 /AC cat...

Visible light photocatalytic activity of rutile TiO2 fiber clusters in the degradation of terephthalic acid

“…Many synthetic methods were developed to produce rutile TiO 2 such as thermal hydrolysis, microemulsion, solgel, hydro-and solvothermal, thermal annealing, and sonochemical [3,9,14,[18][19][20][21][22][23][24][25][26][27][28][29][30]. They have different drawbacks; some of them are complex, require high energy or special equipment, cause a low yield, or need calcination at high temperature for phase transition.…”

“…Yener and Helvacı [32] studied the synthesis and photocatalytic performances of SiO 2 -supported rutile TiO 2 particles in the degradation of TPA under UV-C illumination. Yuefeng et al [28] and Shafaei et al [33] studied the photocatalytic degradation of TPA under UV-C illumination using commercial TiO 2 consists of anatase and rutile phases and activated carbon-supported anatase TiO 2 , respectively, as photocatalysts. Therefore, as a novelty, in the present study the photocatalytic activities of rutile TiO 2 particles were evaluated in the degradation of TPA in a slurry reactor under visible light illumination.…”