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Bismuth tungstate (Bi2WO6) was well known for its low price, nontoxicity and stability in the removal of organic pollutions. However, poor visible light absorption and fast carrier recombination led to its moderate activity. Therefore, a Z-scheme photocatalyst constructed by Bi2WO6 nanosheets, graphene oxide (GO) and silver bromide (AgBr) nanoparticles was successfully prepared. Previous reports suggested that Z-scheme structure based on Bi2WO6 nanosheets could obtain more active sites. And characterization results clarified that the addition of AgBr brought broadened visible light response range, inducing more photocarrier generation. Meanwhile, the optimized Z-scheme composite 15%AgBr/5GO/Bi2WO6 (15A/5G/BW) possessed accelerated interfacial charge separation and transfer, which was resulted from excellent electron conductivity in GO. As a result, 15A/5G/BW exhibited superior photocatalytic activities for tetracycline hydrochloride (TC). The highest degradation efficiency could reach 84% under visible light illumination, and the kinetic constant was 0.0515 min−1 which was approximately 4.60 and 3.16 times higher than that of AgBr and Bi2WO6, respectively. Furthermore, liquid chromatography-mass spectrometry (LC-MS) and trapping experiments revealed possible TC degradation pathways and main active radicals during photocatalysis process. A facial strategy for rational design of ternary photocatalyst towards the degradation of refractory antibiotics was proposed.

Pyrogenic carbonaceous materials (PCM) with diverse surface functionalities are recently described as efficient, heterogeneous, nonmetallic mediators or catalysts, and show excellent performances in the degradation of organic contaminants. Herein, surface functionalities considered to be responsible for the reactivity of PCM are overviewed. It is shown that chemical surface functionalities of PCM can mediate the production of reactive species from oxygen, peroxides, persulfate, ozone for contaminants elimination, including oxygen functionalities, nitrogen functionalities, sulfur functionalities, and persistent free radicals. The possible generation processes of various reactive species promoted or inhibited by surface functionalities and the underlying reaction mechanisms of the further organic transformations are also summarized. The reaction mechanisms of electron transfer, addition and hydrogen abstraction are established. Furthermore, the applications of PCM mediators in aquatic environment, soil and atmosphere are presented to highlight the bright application prospects, and future prospects for the organic contaminant degradation mediated via PCM are proposed.

The growing concerns over the environmental toxicity of sulfonamides (SNs) require immediate action to establish efficient and sustainable processes to address this issue. Adsorption, photodegradation and Fenton/Fenton-like reactions are the most applied processes to remove SNs. However, the adsorption behavior, degradation mechanisms and toxicity of intermediates need further investigation to guide engineering applications. The review focuses on the recent progress and challenges on adsorption, photodegradation and Fenton/Fenton-like techniques for SNs removal. In addition, influences of solution pH and matrix components on adsorption mechanisms are discussed. In particular, the degradation pathway of SNs and toxicity assessment of their intermediates are also analyzed. Finally, conclusions and research gaps in this field are briefly proposed. Publications on this topic have grown exponentially over the last decade. This review provides a unique and comprehensive environmental perspective, as well as the latest knowledge on SNs adsorption and reactive removal by different technologies.

Since the global energy demand and consumption increased sharply, photocatalytic water splitting becomes a promising solution to provide continuous and sustainable energy resources. However, exploring photocatalysts that could meet energy needs and put into industrial manufacture remains a challenging task. Metal-organic frameworks (MOFs), as a class of porous crystalline materials with tailorable structure and ultrahigh surface area, are regarded as an ideal candidate for photocatalysis application. Recently, their peculiar employment in photocatalytic water splitting aroused tremendous interests. Although this topic still in early stage, recent advanced experiments results have certified its potential for future application. This review starts with the fundamentals of photocatalytic water splitting, and subsequently summarizes and exemplifies recent developments of MOFs based- and derived-photocatalysts for water splitting, including water-splitting half reaction and overall water splitting. Particularly, two strategies to enhance photocatalytic performance of MOFs are specific emphasized, namely functional modification and surface or pore decoration. Finally, this review identifies the scarcities of MOFs based- and derived-photocatalysts and proposes pertinent suggestions for further improvement, whilst highlights a green future for photocatalytic water splitting.