Cr(Ⅵ)-乙酸复合体系中硫酸盐掺杂的含钛高炉渣光催化还原Cr(Ⅵ)

采用煅烧的硫酸盐掺杂的含钛高炉渣作光催化剂,研究了Cr(Ⅵ)-乙酸(AA)复合体系中Cr(Ⅵ)的光催化还原效率,考察了初始pH值、cr(Ⅵ)初始浓度、AA/Cr(Ⅵ)体积比、协同效率因子、光催化剂使用寿命等因素的影响.结果表明,增大AA/Cr(Ⅵ)比到0.2%,Cr(Ⅵ)的还原效率先增大到27.55%随后逐渐降低.酸性条件下,Cr(Ⅵ)单一体系和Cr(Ⅵ)-AA复合体系中Cr(Ⅵ)的还原率和吸附率都明显提高;相同反应时间下(110 min),初始pH 1.5时,2种体系中Cr(Ⅵ)的还原效率分别为76.32%(单一体系)和100%(复合体系).复合体系中协同效率因子始终大于0.循环使用5次后催化剂对Cr(Ⅵ)的光催化还原率为92.2%.Cr(Ⅵ)在Cr(Ⅵ)-AA体系中的光催化还原遵循Langmuir-Hinsheiwood 动力学规律.     

Cr（VI）-乙酸复合体系中硫酸盐掺杂的含钛高炉渣光催化还原Gr（VI）

采用煅烧的硫酸盐掺杂的含钛高炉渣作光催化剂,研究了Cr（VI）-乙酸（AA）复合体系中Cr（VI）的光催化还原效率,考察了初始pH值、Cr（VI）初始浓度、AA／Cr（VI）体积比、协同效率因子、光催化剂使用寿命等因素的影响。结果表明,增大AA／Cr（Vi）比到0.2％,Cr（VI）的还原效率先增大到27.55％随后逐渐降低。酸性条件下,Cr（VI）单一体系和Cr（VI）-AA复合体系中Cr（VI）的还原率和吸附率都明显提高;相同反应时间下（110m／n）,初始pH1.5时,2种体系中Cr（VI）的还原效率分别为76.32％（单一体系）和100％（复合体系）。复合体系中协同效率因子始终大于0。循环使用5次后催化剂对Cr（VI）的光催化还原率为92.2％。Cr（VI）在Cr（VI）-AA体系中的光催化还原遵循Langmuir-Hinshelwood动力学规律。     

酸度及酸介质对硫酸盐掺杂的含钛高炉渣光催化还原Cr (Ⅵ)的影响

利用高能球磨法制备了钙钛矿型硫酸盐掺杂的含钛高炉渣光催化剂,探讨了该催化剂的光催化原理,并系统地研究了不同酸度及酸介质对钙钛矿型硫酸盐掺杂的含钛高炉渣光催化还原Cr (Ⅵ)效率的影响。结果表明,酸度以及酸介质对六价铬的光催化还原效率都有十分重要的影响。在强酸性条件下（pH=1.5）,六价铬的光催化还原效率最高;且随着pH值的增大,六价铬的光催化还原效率显著降低。不同酸根离子对STBBFS催化剂光催化还原六价铬的促进作用按PO₄^3-＜NO₃^-＜Cl^-＜SO₄^2-逐渐增强;在光催化反应8 h后,六价铬的还原率差别显著,分别为9.32％、48.73%、100％、100％。因此,为了获得较高的光催化效果,必须控制六价铬废水的pH值以及用硫酸调节溶液的酸度。     

硫酸盐修饰的含钛高炉渣吸附去除水溶液Cr(Ⅵ)

由高能低温煅烧制备了硫酸盐修饰的含钛高炉渣(sulfate-modified titanium-bearing blast furnace slag,STBBFS)吸附剂.用X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)、Fourier转换红外光谱(Fourier transform infrared spectroscopy,FTIR)、X射线衍射和扫描电镜对吸附剂的成分、物相以及表面结构进行了表征.研究了STBBFS的初始质量浓度、溶液pH值、温度对溶液中Cr(Ⅵ)吸附过程的影响.结果表明:Cr(Ⅵ)在STBBFS吸附剂表面上的吸附遵循Langmuir吸附等温线模型;最大吸附容量在pH=1.5时最大,为8.25mg/g.不同吸附温度和初始浓度下,Cr(Ⅵ)的吸附过程都遵循二级吸附动力学模型.通过计算Cr(Ⅵ)吸附过程中的热力学参数:焓变化△H°、自由能变化△G°、熵变化△S°,得出Cr(Ⅵ)吸附至STBBFS吸附剂表面具有自发性,且升高温度易于Cr(Ⅵ)的吸附.根据XPS和FTIR分析结果,可以认为Cr(Ⅵ)先吸附至吸附剂表面,然后被还原为Cr(Ⅲ).     

含钛高炉渣催化剂光催化降解亚甲基蓝

实验制备了含钛高炉渣光催化剂,负载于玻璃表面,通过对水溶液中染料亚甲基蓝的降解实验,研究了含钛高炉渣的光催化效果,评价了含钛高炉渣光催化剂与热处理温度、溶液的pH值、不同光源、空气流量的影响关系. 结果表明,经处理的含钛高炉渣催化剂具有光催化性,经600oC处理的催化剂的光催化性最好,适当的pH值与空气通入量、提高紫外光强度及缩短光源的波长均有助于染料的降解.     

混合硫酸盐还原菌群还原Cr(Ⅵ)的初步研究

利用驯化后的耐受Cr(Ⅵ)的混合硫酸盐还原菌群处理含Cr(Ⅵ)废水,探讨了pH值、培养温度等对Cr(Ⅵ)去除率的影响。结果表明,当Cr(Ⅵ)浓度为50 mg·L-1、pH值为7.0、培养温度为36℃、培养时间为36 h时,该混合菌群对Cr(Ⅵ)的去除率达到最高,为97.6％。该混合菌群能适应较宽的pH值和温度范围且处理...     

光催化法处理含Cr(VI)废水的研究

采用P 25 TiO2作为光催化剂,研究了废水的pH值、Cr(VI)的初始浓度、气氛及有机物等因素对含铬废水中Cr(VI)去解率的影响。结果表明,在pH值为3.0时,光催化反应速率最大;反应气氛对该体系中Cr(VI)的光催化还原无明显影响;苯酚、葡萄糖等有机物的存在能有效地促进Cr(VI)的光催化还原,当加入与Cr(VI)等物质的量的苯酚或葡萄糖时,150 mL反应液[Cr(VI)浓度为0.96 mmol/L],0.15 g光催化剂,经12 W紫外灯照射反应120 m in,Cr(VI)完全被去除,相对于在反应体系中不加有机物时,Cr(VI)光催化还原效率提高了近100%;Cr(VI)的光催化还原符合L-H动力学规律。     

含钛高炉渣抗金黄色葡萄球菌的性能

以含钛高炉渣(titanium-bearing blast furnace slag,TBBFS)为原料,制备了粉状抗菌材料.采用抑菌环抗菌标准确定材料的抗菌性能.通过对金黄色葡萄球菌(staphylococcus aureus,sa)的生物抗菌实验,评价经过改性处理后的TBBFS的抗菌性能.结果表明:在800℃焙烧后的TBBFS粉体具有良好的抗sa性能;无掺杂样品的抑菌环厚度为4.7mm,氯化银(AgCl)掺杂后材料的抗菌性增强,抑菌环随掺杂比例的上升略有增大,氧化铜(CuO)掺杂降低了材料的抗菌性能.     

含钛高炉渣制备复合吸附剂及其铬吸附性能

Cr(Ⅵ)是一种有害污染物,既污染水环境,也会对人体造成伤害。本文以工业固废含钛高炉渣为原料,通过酸浸得到浸出渣基体,经壳聚糖改性,制备一种新型GLZ-jcz/CS复合吸附剂,用来去除废水中的Cr(Ⅵ)。研究了吸附温度、废水pH、吸附剂量、Cr(Ⅵ)初始浓度、吸附时间对Cr(Ⅵ)吸附性能的影响。以Cr(Ⅵ)吸附率为评价指标,确定最优实验条件,并研究了GLZ-jcz/CS复合吸附剂的再生性能。采用扫描电子显微镜、傅里叶红外变换光谱仪、X射线光电子能谱仪、BET比表面积测试仪对GLZ-jcz/CS复合吸附剂进行表征,结合吸附动力学模型和吸附等温线模型分析,确定吸附机理。实验结果表明：当吸附温度为70℃、废水pH=4、吸附剂用量为0.13g、Cr(Ⅵ)初始浓度为50mg/L、吸附时间为2h时,吸附率达到99.8%,吸附容量可以达到67mg/g,GLZ-jcz/CS复合吸附剂经过6次洗脱,吸附率仍可达到96%以上,吸附模型符合拟二级动力学模型和Langmuir吸附等温模型。     

电沉积ZnO薄膜光催化还原Cr(Ⅵ)

采用电沉积法在导电玻璃上制备了ZnO薄膜,用X-射线衍射仪和扫描电子显微镜对其进行了表征.研究了各种因素对电沉积ZnO薄膜光催化还原Cr(Ⅵ)的影响.结果表明,空穴清除剂的存在是光催化还原Cr(Ⅵ)的重要条件;酸性介质中,Cr(Ⅵ)光催化还原率最高;Cr(Ⅵ)光催化还原率随Cr(Ⅵ)浓度的减小而增加;NO3 、SO42-和Ni2+等共存离子明显抑制了Cr(Ⅵ)的还原;而Cu2+则有着显著的促进作用.在pH=4.0和c(柠檬酸)为1.2mmol/L的条件下,经过60min的反应后,0.1mmol/LCr(Ⅵ)在ZnO薄膜上的光催化还原率达到96%.     

钢渣颗粒对水中Cr(VI)的吸附与还原作用

以钢渣颗粒为水处理剂,分析了其组成和结构,研究了钢渣颗粒直接吸附去除水中Cr(VI)的工艺过程及机理. 结果表明,钢渣颗粒在适当的粒度与用量下,经10 min搅拌处理,水中Cr(VI)浓度由200 mg/L降低到0.5 mg/L,达到《污水综合排放标准》(GB8978-1996)的要求. 钢渣颗粒对水中Cr(VI)的吸附符合Langmuir等温吸附过程,对Cr(VI)的饱和吸附量达6.878 mg/g. 化学分析和XPS分析均表明,钢渣颗粒对水中Cr(VI)具有吸附与还原的联合作用,吸附后钢渣颗粒中Cr(III)含量由0.0985%提高到0.39%,而FeO含量由9.20%下降到8.35%. 吸附后钢渣颗粒表面形成了Cr(OH)3,说明钢渣颗粒中FeO充当了还原剂,将水中Cr(VI)吸附于钢渣颗粒表面并还原成了低毒的Cr(OH)3随钢渣颗粒沉降直接从水中去除.     

啤酒酵母吸附Cr（VI）的动力学及热力学研究

研究啤酒酵母对溶液中铬(VI)的吸附效果和机理,通过红外对吸附前后菌体表面特征分析,表明Cr (VI)与菌体表面基团发生配位络合反应.结果表明,在温度为35 ℃,pH=2,Cr(VI)初始浓度为20 mg/L时达到最大吸附量,最大吸附量为4.19 mg/g.酵母菌对Cr(VI)的吸附行为基本符合Langmuir方程,并且在 25,30和35 ℃条件下的理论最大吸附量qmax分别为4.472,4.533,4.702 mg/g.动力学研究表明,反应在240 min吸附基本达到平衡状态,准二级动力学模型能够更好的描述吸附过程.不同温度下的吸附热力学显示,该吸附过程为自发的吸热反应.     

Boron-Doped Diamond Electrode Performance in Cr(VI) Reduction Using Synthetic and Plating Wastewater

The goal of this work was to evaluate the effectiveness of iron and boron-doped-diamond (BDD) as cathodic electrodes on the reduction of Cr(VI) in synthetic and wastewater samples. The pH and electrolyte composition were varied, and the effect on the Cr(VI) reduction rate was measured. The optimized conditions from the synthetic water Cr(VI) reduction experimental data, were tasted on electroplating wastewater. The results indicated that both a pH of 2 and the use of NaCl as an electrolyte significantly increase the Cr(VI) reduction rate for all synthetic systems, especially the iron-BDD system. The Cr(VI) reduction rate in Fe-BDD systems was also affected by nitrate and sulfate ions. In the case of electroplating wastewater, Cr(VI) reduction by BDD cathodes was faster than with iron cathodes, achieving a complete reduction of 180 mg Cr(VI)/L in 25 min, with 40% less sludge produced. The elemental composition of sludge was analyzed using SEM/EDS and X-ray spectroscopy to confirm that iron and chromium precipitated out of the solution. The sludge had a chemical composition of (31.9%) Fe₂O₃, (29.6%) FeOOH, (21%) FeO, and (17.4%) FeSO₄. Therefore, BDD as an electrode material effectively reduces Cr(VI) in electroplating wastewater, and can be effectively scaled up to industrial applications.     

Well-designed ZnIn2S4/TiO2 Z-type heterojunction for efficient photocatalytic reduction of Cr(VI)

ZnIn₂S₄/TiO₂ photocatalyst was obtained by a facile hydrothermal method. Various techniques were used to characterize the ZnIn₂S₄/TiO₂, crystal structure and optical properties of ZnIn₂S₄/TiO₂. Cr (Ⅵ) as highly-toxic pollutant was used as the target reduction product to evaluate the catalytic performance of ZnIn₂S₄/TiO₂ under visible light irradiation. According to the experiment results, the reduction rate of Cr(VI) in the presence of ZnIn₂S₄/TiO₂ reaches 99% within 60 min, which is much better than ZnIn₂S₄ and TiO₂, respectively. At the same time, ZnIn₂S₄/TiO₂ also performs good stability for reduction rate hardly changes after 5 recycling experiments.     

Gamma irradiated orange peel for Cr(VI) bioreduction

This work presents the γ irradiation (600–3500 kGy) and acid hydrolysis onto orange peel for hexavalent chromium removal. SEM, AFM, TGA-DSC, FTIR, and UV-Vis showed that γ rays enhance degradation and cleavage of orange peel cellulose polymeric chains, increasing the presence of reducing sugars after acid hydrolysis (0.1552 g/g biomass, 3500 kGy). Bioreduction kinetics of Cr(VI) using both solid and solubilized liquid fractions of γ irradiated biomass showed a direct correlation between the applied dose and Cr(VI) removal, reaching 100% of Cr(VI) reduction at pH 2 and 3500 kGy. Cr(VI) reduction is explained as a function of hydrolyzed reducing sugar oxidation.     

Separation of Cr(VI) from Water by Green Reduction Reaction and Adsorptive Removal on Gelatin-Grafted-Yeast Biosorbent

A green chemical method was explored and described for separation and extraction of the toxic hexavalent chromium from aqueous solutions and real water samples. A green reduction reaction for the transformation of toxic hexavalent chromium into the nontoxic trivalent chromium ion was performed by using hydrogen peroxide. The produced Cr(III) was then extracted by biosorption on the surface of a novel and eco-friendly gelatin-grafted-baker’s yeast (Gelatin-Yeast) biosorbent. The investigated biosorbent was characterized by high capacity value of the reduced trivalent chromium species in pH 6.0 as 1.120 mmol g^?1. The biosorption processes were examined, monitored, and optimized in different experimental and controlling parameters. The potential applications of Gelatin-Yeast for separation and removal of Cr(VI) from real industrial and sea water samples were also studied.     

Nanorod-pillared mesoporous rGO/ZnO/Au hybrids for photocatalytic Cr (VI) reduction: Enhanced Cr(VI) adsorption and solar energy harvest

Herein, we fabricated mesoporous ternary hybrids composed of Au-functionalized ZnO nanorods grown on rGO nanosheets. The ZnO nanorods distributed on the rGO nanosheets can act as a pillaring layer to avoid the agglomeration of rGO, leading to the formation of abundant mesopores within the hybrids. The high-surface-area, mesoporous hybrids can offer sufficient active sites and transport channels for efficient adsorption and diffusion of Cr(VI), which was favorable for its photocatalytic reduction due to the adsorption enrichment effects. Moreover, the plasmonic-induced visible-light absorption of Au nanoparticles and efficient charge separation by rGO synergistically contributed to the significantly improved solar-light-driven photocatalytic Cr(VI) reduction properties of the ternary hybrids.