Photocatalytic degradation is an eco-friendly and efficient approach for decontaminating wastewater; however, remediation can be hindered by synergistic interactions among multiple pollutants. In this work, the S-doped gC3N4/Zn3In2S6/sophora flower-derived carbon dots (SCN/ZIS/CDs) ternary composite was fabricated via hydrothermal method. The photocatalyst exhibited remarkably enhanced visible-light absorption capacity and charge separation efficiency relative to monocomponent systems. The as-prepared composite exhibited excellent photocatalytic activity, demonstrating 99.2% degradation of rhodamine B (RhB) within 50 min and nearly complete reduction of Cr(VI) (99.5%) within 10 min under visible light irradiation. The degradation rate constants of SCN/ZIS/CDs-ii are 8.3 times higher than those of S-doped g-C3N4 (SCN) and 1.7 times higher than those of S-doped g-C3N4/Zn3In2S6 (SCN/ZIS), indicating a significant synergistic effect. The photocatalytic activity of SCN/ZIS/CDs-ii exhibited excellent stability throughout four continuous cycles involving the degradation of multiple pollutants. Additionally, radical scavenger experiments confirmed that superoxide (& sdot;O2-) and hydroxyl radicals (& sdot;OH) were the main reactive species driving photocatalytic degradation with SCN/ZIS/CDs. The results confirm that SCN/ZIS/CDs represent a candidate for future photocatalytic applications due to their exceptional performance and environmental compatibility.

The selection of simple and effective photocatalysts is a challenge for removing Norfloxacin (NOR) from water. This study successfully synthesized CuO nanoclusters and titanium dioxide (CuO/TiO2) Z-scheme heterojunction using the facile in situ self-growing method and used for photocatalytic degradation of NOR. The 1.4 % CuO/ TiO2 system achieves an 84.88 % NOR degradation efficiency in 60 min and maintains over 78.42 % efficiency after five cycles when exposed to visible light, which is higher than that of CuO and TiO2, respectively. The internal electric field established between them expedited the separation and transfer of electron-hole pairs, thereby boosting photocatalytic activity. Moreover, the active species that take part in the photocatalytic reaction were identified as center dot O-2(-), center dot OH, and h(+) radicals. According to the mass spectrometry (MS) test, the possible three photocatalytic degradation pathways of NOR were investigated. Finally, the heterojunction formation and charge transfer mechanism of CuO/TiO2 are proposed and validated with DFT calculation. This study applies simple, low-cost CuO/TiO2 for efficient NOR degradation under visible light, providing an insight into the scaleup removal of NOR from water.

Bi4O5Br2 material exhibits excellent performance in photocatalytic degradation of antibiotics, but high recombination rate of photoexcited electron-hole pairs limits its photocatalytic activity. Attapulgite (ATP) is an excellent candidate for load type catalyst due to its larger specific surface area. As a new type of carbon-based nanomaterials, carbon dots (CDs) have important application prospects in catalysis and other fields. Herein, Z-scheme CDs/Bi4O5Br2/ATP composite photocatalyst loaded with varied proportions of CDs was synthesized by dynamic adsorption method, which demonstrated excellent photocatalytic degradation performance by lowering the recombination rate of photoexcited electron-hole pairs. Ciprofloxacin degradation efficiency by 3 wt% CDs/Bi4O5Br2/ATP can reach up to 90% within 120 min under simulated sunlight, in addition, the 3 wt% CDs/Bi4O5Br2/ATP composite photocatalyst has good stability. As a result, our research helps to prepare high-efficiency Z-scheme heterojunction and contributes to study the degradation of antibiotics in the aquatic environment.

Bi4O5Br2 material exhibits excellent performance in photocatalytic degradation of antibiotics, but high recombination rate of photoexcited electron-hole pairs limits its photocatalytic activity. Herein, Z-scheme CDs/Bi4O5Br2/ATP composite photocatalyst loaded with varied proportions of CDs was synthesized by dynamic adsorption method, which demonstrated excellent photocatalytic degradation performance by lowering the recombination rate of photoexcited electron-hole pairs. Ciprofloxacin degradation can reach up to 90% in 120 minutes, while the CDs/Bi4O5Br2/ATP composite photocatalyst has great stability. This work also provided a plausible photodegradation pathway for the CDs/ Bi4O5Br2/ATP composite photocatalyst to ciprofloxacin. Furthermore, the highest kinetic constant of the 3wt% CDs/Bi4O5Br2/ATP composite photocatalyst (K=0.0178min-1) is 6.77 times that of pure Bi4O5Br2 (K=0.00263min-1). As a result, our research helps to prepare high-efficiency Z-scheme heterojunctions and contributes to the understanding of antibiotic degradation in aquatic environments.

为了解决富营养化河道中内源磷释放的问题,合成了一种新型磷负荷控制材料,即负载有碳酸钙微粒的高岭石复合材料(CLK),研究了其对底泥磷释放和磷组分的影响.结果发现,CLK能有效抑制底泥释磷,最佳投加量为100mg/g,2h内即将水中溶解态磷(SRP)浓度控制在0.021 mg/L.CLK的添加促使底泥中的可交换态磷(Ex-P)、铝结合态磷(Al-P)和铁结合态磷(Fe-P)向钙结合态磷(Ca-P)转变,其中Fe-P含量减少了 17.31％,Ca-P含量增加了 27.91％,有效降低了底泥磷释放的风险.

为研究芽孢杆菌投加到黑臭水体中不同位置对河道水体的修复效果,以某黑臭河道底泥和水体为研究对象,利用芽孢杆菌生物降解技术,分别将芽孢杆菌投加至底泥、泥水分界面、上覆水体3个不同位置,并测定相应指标进行分析.结果表明:芽孢杆菌投加至不同位置对黑臭水体均有修复效果,其中将芽孢杆菌投加至泥水分界面时对黑臭底泥和水体的修复效果最佳,此时对水体中氨氮、总氮、TP和COD的去除率分别为63.65％、42.71％、39.14％和63.13％,对底泥中氨氮、总氮、TP和有机质的去除率分别为59.88％、65.99％、59.07％和57.07％,底泥颜色由黑变黄,厚度下降18％,底泥生物降解能力增强.

为去除生活与工业污水中的磷酸盐,通过氧化钙与碳酸钠的联合作用,对高岭石进行连续改性,将碳酸钙引导至黏土层,制备了改性高岭石/碳酸钙复合吸附材料(KCA).利用SEM,XRD,FT-IR对KCA进行表征,并结合零电荷点 、吸附动力学 、吸附等温线 、实际废水研究KCA对磷酸盐的吸附特性.结果表明:KCA吸附量显著提升达到8.03 mg/g;KCA表面硅醇基团增加,并负载有碳酸钙颗粒层;KCA在水溶液中表面带正电,吸附磷酸盐的过程符合准二级动力学与Langmuir吸附模型.

Carbon dots (CDs) and Bi-riched bismuth oxyhalide have great potential in the field of photocatalysis. Here, a series of CDs/Bi4O5Br2 at different loading ratios were successfully synthesized by solvothermal method. Experiments of visible light degradation of ciprofloxacin (CIP) showed that 3 wt% CDs/Bi4O5Br2 had the highest activity (5.39 times that of Bi4O5Br2) and the degradation rate reached 98%. The samples were characterized by XRD, SEM, TEM, EDS, Mapping, UV-vis DRS, Raman, and PL spectra. The absorption edge of 3 wt% CDs/Bi4O5Br2 was red-shifted from 455 nm to 580 nm compared with Bi4O5Br2. The enhancement of photocatalytic activity was mainly due to the fact that the addition of CDs not only broadened the photo-response range, but reduced the recombination rate of photo-induced carriers with good electron transport interfaces formed. (C) 2019 Elsevier B.V. All rights reserved.