The decontamination of bisphenol A (BPA) from aqueous solution by graphene adsorption was investigated. The maximum adsorption capacity (q(m)) of graphene for BPA obtained from a Langmuir isotherm was 182 mg/g at 302.15 K, which was among the highest values of BPA adsorption compared with other carbonaceous adsorbents according to the literature. Both π-π interactions and hydrogen bonds might be responsible for the adsorption of BPA on graphene, and the excellent adsorption capacity of graphene was due to its unique sp(2)-hybridized single-atom-layer structure. Therefore, graphene could be regarded as a promising adsorbent for BPA removal in water treatment. The kinetics and isotherm data can be well described by the pseudo-second-order kinetic model and the Langmuir isotherm, respectively. The thermodynamic studies indicated that the adsorption reaction was a spontaneous and exothermic process. Besides, the presence of NaCl in the solution could facilitate the adsorption process, whereas the alkaline pH range and higher temperature of the solution were unfavorable.

The influence of defects on the photoactivity of ZnO has been revealed. The defects can be formed via ball-milling treatment, and part of the defects can be repaired via annealing treatment. The photocatalytic activity of the ZnO sharply decreased as the ballmilling speed and milling time increased. After the annealing treatment, the photocatalytic activity recovered partly but could not return to the activity of the pristine ZnO. The bulk defects such as oxygen vacancies (V O ), zinc vacancies (V Zn ) and a lot of nonradiative defects were formed after the milling treatment. The annealing treatment can only repair part of the bulk defects and nonradiative defects. Thus, only part of the photoactivity was recovered. The species trapping experiments showed that the introduction of the bulk defects did not change the photocatalytic mechanism. The main oxidative species for the pristine ZnO, the milled ZnO, and the annealed ZnO are photogenerated holes and hydroxyl radicals.

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Fullerene (C60)-modified Bi2WO6 photocatalyst is prepared by a simple absorbing process. The as-prepared samples show the high efficiency for the degradation of nonbiodegradable azodyes methylene blue (MB) and rhodamine B (RhB) under visible light (lamda >420 nm) and simulated solar light (lamda >290 nm). After being modified by C60, the photocatalytic activities of Bi2WO6 samples increase about 5.0 and 1.5 times for the degradation of MB and RhB under visible light irradiation, whereas 4.6 and 2.1 times under xenon lamp irradiation, respectively. The enhanced photocatalytic activity for C60-modified Bi2WO6 comes from the high migration efficiency of photoinduced electrons on the interface of C60 and Bi2WO6 which is produced by the interaction of Bi2WO6 and C60 with the conjugative pi-system. The optimum synergetic effect is found at a weight ratio of 1.25 wt % (C60/Bi2WO6). The photocatalytic reaction process of C60-modified Bi2WO6 is mainly governed by direct holes and O2*- oxidation.