苯醌对聚合硅酸铁多相UV-Fenton体系的增效机制

通过构建苯醌增效聚合硅酸铁多相UV-Fenton体系,讨论了体系中橙Ⅱ的脱色和降解途径.在研究苯醌浓度对聚合硅酸铁铁离子的释放、Fe²⁺与Fe³⁺之间的转化、H₂O₂分解和·OH生成影响的基础上,提出了苯醌对聚合硅酸铁多相UV-Fenton体系的增效机制.结果表明,随苯醌浓度的增加,其紫外光下光解还原聚合硅酸铁并释放Fe²⁺的程度增大、H₂O₂分解速度加快、产生·OH浓度峰值增高且出现的时间提前;苯醌增效体系释放于溶液中的Fe²⁺可以通过Fenton反应转化成Fe³⁺,反应结束后聚合硅酸铁能重新吸附Fe³⁺并使其浓度降低,避免了增效体系铁离子的二次污染.本研究将为多相催化剂催化过程的调控提供新的视角,为多相光助-芬顿反应在有机废水资源化中的应用提供理论依据和技术支持.     

Adsorptive removal of phosphate by the bimetallic hydroxide nanocomposites embedded in pomegranate peel

This study aimed to fabricate new and effective material for the efficiency of phosphate adsorption. Two types of adsorbent materials, the zirconium hydroxides embedded in pomegranate peel (Zr/Peel) and zirconium-lanthanum hydroxides embedded in pomegranate peel (Zr–La/Peel) were developed. Scanning electronic microscopy (SEM), x-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD) were evaluated to give insight into the physicochemical properties of these adsorbents. Zr–La/Peel exceeded the adsorption efficiency of Zr/Peel adsorbents in batch adsorption experiments at the same pH level. The peel as a host can strive to have a strong “shielding effect” to increase the steadiness of the entrenched Zr and La elements. La and Zr are hydroxide metals that emit many hydrogen ions during the hydrolysis reaction, which contribute to protonation and electrostatic attraction. The highest adsorption capacity of La–Zr/Peel for phosphate was calculated to be 40.21 mg/g, and pseudo second-order equation is very well fitted for kinetic adsorption. Phosphate adsorption efficiency was reduced by an increase of pH. With the background of coexisting Cl^?, little effect on adsorption efficiency was observed, while adsorption capacities were reduced by almost 20–30% with the coexistence of ${{\text{SO}}_4}^{2?}$, ${{\text{NO}}_3}^{?}$ and humic acid (HA).     

SiO_2-TiO_2纳米管的制备及其光催化性能的研究

文章采用水热法制备SiO2-TiO2纳米管,通过扫描电镜(SEM)和透射电镜(TEM)考察了该纳米管的结构形态,并用X-射线衍射考察其晶体结构。实验结果表明所制得的纳米管是锐钛晶型,其两端开口,具有多层管壁;管径为8nm左右,管壁厚1～2nm。光催化降解酸性橙Ⅱ实验表明:SiO2-TiO2纳米管光催化速率比TiO2纳米管高出10%。这可能是因为Si元素的存在增大了钛纳米管的比表面积,同时SiO2的存在能降低光生电子和空穴的复合率。     

In situ preparation of g-C3N4/Bi4O5I2 complex and its elevated photoactivity in Methyl Orange degradation under visible light

A graphite carbon nitride(g-C_3N_4) modified Bi_4O_5I_2 composite was successfully prepared insitu via the thermal treatment of a g-C_3N_4/Bi OI precursor at 400°C for 3 hr.The as-prepared g-C_3N_4/Bi_4O_5I_2 showed high photocatalytic performance in Methyl Orange(MO) degradation under visible light.The best sample presented a degradation rate of 0.164 min~(-1),which is 3.2 and 82 times as high as that of Bi_4O_5I_2 and g-C_3N_4,respectively.The g-C_3N_4/Bi_4O_5I_2 was characterized by X-ray powder diffractometer(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Raman,X-ray photoelectron spectroscopy(XPS),ultraviolet-visible diffuse reflectance spectra(DRS),electrochemical impedance spectroscopy(EIS) and transient photocurrent response in order to explain the enhanced photoactivity.Results indicated that the decoration with a small amount of g-C_3N_4 influenced the specific surface area only slightly.Nevertheless,the capability for absorbing visible light was improved measurably,which was beneficial to the MO degradation.On top of that,a strong interaction between g-C_3N_4 and Bi_4O_5I_2 was detected.This interplay promoted the formation of a favorable heterojunction structure and thereby enhanced the charge separation.Thus,the g-C_3N_4/Bi_4O_5I_2 composite presented greater charge separation efficiency and much better photocatalytic performance than Bi_4O_5I_2.Additionally,g-C_3N_4/Bi_4O_5I_2 also presented high stability.·O_2~-and holes were verified to be the main reactive species.     

混凝辅助电化学法处理橙黄G染料废水

以石墨板为阳极,研究了电化学氧化法对橙黄G染料废水的降解效果。比较了在NaCl、Na2 SO4以及NaCl与FeSO4·7H2O组合的支持电解质体系中的处理效果,同时考察了电压、初始pH、电解质浓度、电极间距和电解时间等因素对废水中橙黄G脱色率及COD去除率的影响。研究结果表明,橙黄G的脱色主要是活性氯的氧化作用,橙黄G分子的矿化可能主要是电解过程中产生的·OH的作用,FeSO4·7H2O的加入增加了混凝作用,使得处理效果进一步提高。最佳脱色条件下橙黄G脱色率和COD的去除率分别为97．6％和56．3％,B／C（BOD／COD）由0．09提高至0．41,可生化性有较大改善,并且随着降解时间的增加,COD去除率逐渐升高。此结果表明,橙黄G废水COD的去除相对于脱色存在滞后性。     

Rapid decolorization of Acid Orange II aqueous solution by amorphous zero-valent iron

Some problems including low treatment capacity, agglomeration and clogging phenomena, and short working life, limit the application of pre-treatment methods involving zero-valent iron (ZVI). In this article, ZVI was frozen in an amorphous state through a melt-spinning technique, and the decolorization effect of amorphous ZVI on Acid Orange II solution was investigated under varied conditions of experimental variables such as reaction temperature, ribbon dosage, and initial pH. Batch experiments suggested that the decolorization rate was enhanced with the increase of reaction temperature and ribbon dosage, but decreased with increasing initial solution pH. Kinetic analyses indicated that the decolorization process followed a first order exponential kinetic model, and the surface-normalized decolorization rate could reach 2.09 L/(m². min) at room temperature, which was about ten times larger than any previously reported under similar conditions. Recycling experiments also proved that the ribbons could be reused at least four times without obvious decay of decolorization rate and efficiency. This study suggests a tremendous application potential for amorphous ZVI in remediation of groundwater or wastewater contaminated with azo dyes.     

Treatment of azo dye Orange II in a sequential anaerobic and aerobic-sequencing batch ractor system

We studied the biodegradation of Orange II in a sequential anaerobic and aerobic-sequencing batch reactor system. Granular activated carbon was used either packed into a column or added directly into the anaerobic reactor to investigate the treatment performance between the two operation conditions. We found that the circulation of mixed liquor between the anaerobic reactor and the carbon-packed column enhanced the chemical oxygen demand from 28 to 52% and Orange II removal efficiencies from 88 to 96%, under simultaneous adsorption and biodegradation process. The morphology of microbes was observed under an electron-scanning microscope.     

基于响应面优化条件下柚皮对Pb2+的吸附

采用Plackett-Burman(P-B)法和中心复合设计(Central Composite Design,简称CCD)对影响柚皮吸附Pb2+的6个条件进行筛选优化.P-B实验设计与统计学分析表明:pH值、Pb2+初始浓度、吸附剂用量是影响吸附率的3个关键因素.以吸附率为响应目标,对3因素进行中心复合设计,并经响应面法优化分析得到影响吸附率的二阶模型,确定了Pb2+吸附实验的最优操作条件:pH值5.4.Pb2+初始浓度为265.86mg·L-1,吸附剂用量为2.56 g·L-1,实测吸附率达到92.47%,吸附量为96.01 mg·g-1;整个吸附过程吸附剂柚皮没有经过任何化学预处理.效果优于一般的天然吸附剂.研究结果表明,柚皮是一种很具潜力的环保型廉价吸附剂.     

Anaerobic digestion of agro-industrial waste enriched with bovine bone meal for improved biogas production and biofertilization

The increase in animal and agro-industrial production must be accompanied by the development of appropriate waste and by-product management strategies. Anaerobic digestion is a promising approach to recycle these wastes and reintegrate them into the economic production cycle of biogas and biofertilizer. In order to improve the performance of the anaerobic mesophilic digestion of abundant agro-industrial wastes constituted by potato peel (PP), and poultry waste (PW) and study the contribution of bovine bone meal (BB) as additive rich in phosphorus, which can help to neutralize the acidity of the substrate. The 10-point simplex-centroid design and the isoresponse surfaces strategy were used. This study demonstrated that in mesophilic bio-digestion, the using bovine bones in admixture with agroindustrial residue provided for the proper balance of chemical components required for proliferation of microbiological agent of bioconversion, which also resulted in an increase in biogas production capacity. The best formula was so composed by 66.67% bovine bone, 16.67% potatoes peel, and 16.67% poultry waste. The stability was achieved here after only 12 days. The digestate generated from it was fulfilled with the microbiological and chemical requirements for safety defined by the NF U44-551 standard. Germination test revealed that this optimal produced digestate, did not hinder growth, in fact, almost 85% of seed was germinated. Finally, fertilization experiments prove that this digestate can boost the growth of bell pepper (Capsicum annuum).     

改性柚子皮吸附剂对模拟废水中Pb^2＋的吸附性能

以废柚子皮为原料,经ZnCl2浸泡一加热的化学改性手段制备改性柚子皮生物吸附剂,并通过模拟试验研究该吸附剂对废水中Pb^2＋的去除。考察了模拟废水的pH、吸附时间、吸附剂用量和Pb^2＋初始浓度、温度等因素对柚子皮吸附剂去除Pb^2＋的影响,并研究柚子皮吸附剂对Pb^2＋的吸附动力学及吸附特征。结果表明,模拟废水的pH、吸附时间、吸附剂用量和Pb^2＋初始浓度、温度等因素对柚子皮吸附剂吸附废水中Pb^2＋均有显著影响。适宜的吸附条件为pH5．3-6．5,吸附时间1．5h,吸附剂用量10g·L^-1,Pb^2＋初始质量浓度100mg·L^-1,温度30℃。在该条件下,废水中Pb^2＋去除率在90％以上。柚子皮吸附剂对废水中Pb^2＋的吸附符合动力学二级反应方程,等温吸附规律可用Langmuir、Freundlich和Temkin模型进行较好的描述。