Ag/g-C3N4可见光催化技术降解水中磺胺嘧啶的研究

将Ag/g-C3N4(银/石墨相氮化碳)可见光催化技术应用于废水中磺胺嘧啶的去除,考察Ag/g-C3N4对磺胺嘧啶的降解效果、水质因素对降解效果的影响、降解机理、中间产物及其应用于实际水体时磺胺嘧啶的降解情况.结果表明:1)质量分数为5%的Ag/g-C3N4在可见光照射下能将磺胺嘧啶有效降解,去除率高达98.3%,且降解过程符合拟一级动力学模型;2)溶液的pH值和碱度对Ag/g-C3N4降解磺胺嘧啶的效果影响不大,但溶液中腐殖酸的存在对磺胺嘧啶的降解起抑制作用;3)在磺胺嘧啶的降解过程中,·O 2-和光生空穴是主要的活性物种;4)降解过程主要产生4种中间产物,分别为2-氨基嘧啶、对氨基苯磺酸、羟基化磺胺嘧啶和硝基化磺胺嘧啶;5)以松花江水和生活污水的二级出水为水质背景时,Ag/g-C3N4对磺胺嘧啶的去除率分别为95.4%和77.5%.

基于WASP石墨烯可见光催化的水质提升效果研究

为了寻求改善城市人工景观水体水质的可靠方法,文章以合肥市的人工景观水体翡翠湖为研究对象,针对其部分水体黑臭的现状,选择石墨烯可见光催化技术对其进行水质提升实验研究,采用水质分析模拟程序(water quality analysis simulation program, WASP)模型构建翡翠湖水质模型,利用数值模拟的方法以溶解氧(dissolved oxygen, DO)、化学需氧量(chemical oxygen demand, COD)、氨氮(NH_(3)-N)和总磷(total phosphorus, TP)为指标,模拟运用石墨烯可见光催化技术治理后的水质,并通过翡翠湖水质提升项目实验验证结果。结果表明:利用WASP水质模型可以有效地模拟石墨烯可见光催化技术对水体的水质提升效果,经过该技术治理后,翡翠湖实验河段水质在92 d内由劣Ⅴ类水提升至Ⅳ类水水质标准(ρ(COD)≤30 mg/L、ρ(NH_(3)-N)≤1.5 mg/L、ρ(TP)≤0.1 mg/L),为类似黑臭景观水体的水污染治理提供了新的治理方案与思路。

BiOCl-Bi12O17Cl2 nanocomposite with high visible-light photocatalytic activity prepared by an ultrasonic hydrothermal method for removing dye and pharmaceutical

A BiOCl-Bi12O17Cl2 nanocomposite with a high visible-light response and a low photoinduced electron-hole pair recombination rate was successfully synthesized using an ultrasonic-hydrothermal method.The texture,structure,optical,and photocatalytic properties of the composite were characterized.The results showed that the composite had a sheet flower-like structure with a large specific surface area.Ultraviolet-visible diffuse reflection spectra and photoluminescence spectra showed that the composite had an excellent visible-light response and a low recombination rate of photoinduced electron hole pairs.The photocatalytic property of the composite was evaluated by the removal efficiency of rhodamine B and ciprofloxacin under visible-light illumination.The composite’s reaction rate constant of removing rhodamine B(/ciprofloxacin)was approximately 8.14(/4.94),42.63(/11.91)and 64.66(/36.07)times that of Bi12O17Cl2,P25,and BiOCl,respectively.Furthermore,the composite showed a wide applicable pH range and excellent reusability.Mechanism analysis showed that photogenerated holes played a dominant role and·O2–also contributed to photocatalytic degradation.In summary,this study presents a high-efficiency photocatalyst for wastewater treatment.