乳状液膜法治理氧化铁氨氮废水的研究

研究了采用液膜分离技术从氧化铁行业生产氨氮废水中处理氨氮的工艺,并通过实际工业废水进行了验证。主要考察了表面活性剂的用量、外水相pH值、内相试剂的选择、油内比、乳水比等因素对氨氮去除率的影响。通过实验结果表明:以3%EA表面活性剂(质量分数),10%内水相硫酸浓度,油内比为2∶1的乳状液膜体系,处理初始浓度为1057mg/L氧化铁行业氨氮废水,在pH值为11.8,乳水比Rew为1∶8的传质条件下,氨氮去除率可达94%以上。     

水合氧化铁对含磷废水的吸附特性研究

以Fe(NO3)3为前驱物,制备了水合氧化铁吸附剂样品,以NaOH为解吸剂,研究了样品对模拟废水中磷酸根的吸附和解吸性能。结果表明,水合氧化铁对磷酸根有较好的吸附效果;随着pH的降低,水合氧化铁对磷酸根的吸附能力增强,在pH为2时吸附达92.5%;吸附前15 min吸附速率较快,约150 min达到平衡,吸附动力学曲线符合二级动力学模型;用水合氧化铁对初始浓度为50~100 mg/L模拟含磷废水吸附,随着初始浓度的增大,磷的去除率下降;水合氧化铁对磷酸根的吸附等温线较符合Langmuir吸附模型;用NaOH对水合氧化铁行解吸,浓度为40 g/L有最好的解吸率,60 min时达到解吸平衡。     

OPTIMIZATION OF DUAL-MEDIA FILTER PERFORMANCE1

ABSTRACT: Rapid-rate filter with sand or anthracite as filter media was studied at filtration rates of 4.5 and 9.0 m³/m²-h. Different parameters were evaluated by adopting a proposed simplified model. A suitable combination of anthracite-sand as filter media was given by using corresponding filter parameters of single-medium filters and break-even optimization technique.     

兰州市沙尘天气与痤疮门诊量的时间序列

研究沙尘天气、非沙尘天气下颗粒物（PM_2.5、PM_C、PM₁₀）对痤疮门诊量的影响,并进行性别、年龄分层研究,筛选敏感人群.收集了2013~2017年兰州市沙尘期与非沙尘期3家三甲医院痤疮门诊量资料、大气颗粒物及气象数据,采用基于泊松分布的分布滞后非线性模型（DLNM）,控制气象因素、季节性和长期趋势、星期几效应等混杂因素,分析沙尘期与非沙尘期颗粒物对痤疮门诊量的影响及滞后效应.结果表明：沙尘期时,兰州市3家三甲医院痤疮日均门诊量为26人次,范围3~54人次.非沙尘期时痤疮日均门诊量为37人次,范围1~89人次;单污染物模型显示,PM_2.5、PM_C、PM₁₀均在滞后第6d （lag6）时效应量达到最大值,其浓度每增加10μg/m³,痤疮门诊量的超额危险度（ER）及95%可信区间（95% CI）分别为1.065（95% CI：0.260~1.877）、0.355（95% CI：0.018~0.693）、0.310（95% CI：0.054~0.567）,PM_2.5对痤疮门诊量的影响最为显著;性别及年龄分层发现,性别分层中PM_2.5对女性的影响有统计学意义,其浓度每增加10μg/m³,痤疮门诊量增加1.077（95% CI：0.124~2.039）;年龄分层中,0~18岁组受PM_C、PM₁₀影响显著,19~24岁组受PM_2.5、PM₁₀影响显著,各颗粒物对25~34岁组及≥35岁组效应无统计学意义.在非沙尘期时,PM_2.5、PM_C、PM₁₀不引起痤疮门诊量增加.双/多污染物模型显示,分别调整其他污染物后,PM_2.5、PM_C、PM₁₀对痤疮门诊量的影响与单污染物模型类似,仍具有统计学意义.兰州市沙尘天气下大气颗粒物（PM_2.5、PM_C、PM₁₀）可使痤疮门诊量增加,对女性及青少年影响显著.     

Superior trichloroethylene removal from water by sulfide-modified nanoscale zero-valent iron/graphene aerogel composite

Sulfide-modified nanoscale zero-valent iron (S-nZVI) is a promising material for removal of organic pollutants from water, but S-nZVI nanoparticles (NPs) easily agglomerate and have poor contact with organic contaminants. Herein, we propose a new S-nZVI/graphene aerogel (S-nZVI/GA) composite which exhibits superior removal capability for trichloroethylene (TCE) from water. Three-dimensional porous graphene aerogel (GA) can improve the efficiency of electron transport, enhance the adsorption of organic pollutants and restrain the agglomeration of the core-shell S-nZVI NPs. The TCE removal rates of FeS, nZVI, GA and S-nZVI were 27.8%, 42%, 63% and 75% in 2?hr, respectively. Furthermore, TCE was completely removed within 50?min by S-nZVI/GA. The TCE removal rate increased with increasing pH and temperature, and TCE removal followed the pseudo-first-order kinetic model. The results demonstrate the great potential of S-nZVI/GA composite as a low-cost, easily separated and superior monolithic adsorbent for removal of organic pollutants.     

外磁场调控的聚合硫酸铁水解过程研究

基于聚合硫酸铁的UV-vis光谱学特征,利用外加电磁场对聚合硫酸铁进行磁化调控,研究了不同磁化时间和磁场强度对PFS中铁形态分布的影响.研究表明,水解过程中铁盐逐渐与羟基结合,存在由低聚态向相对较高聚态转化的趋势.整体来看,在一定范围内增加磁化时间和磁场强度可以有效促进絮凝剂的水解,但是在多工艺参数调控中,提升磁场强度能够获得更为明显的效果.通过上述研究表明,借助UV-vis光谱学特征变化的分析,可有效判断PFS在水解过程中的水解进程及转化.在相同磁场强度下,磁化4~6min时,由低聚态向高聚态转化速率更快.而在控制磁化时间相同的情况下,增大磁场强度相应水解产物的转化速率也会提高1.9%~12.3%.该研究为设计适当的磁场强度获得更好的磁絮凝效果以及PFS絮凝工艺的调控提供更为科学有效的理论指导.     

铁铝吸附剂对起爆药污染土壤中锑的稳定化研究

采用3种铁基吸附剂（FeSO₄•7H₂O、针铁矿、Fe⁰）和铝基吸附剂（Al（OH）₃）,对某起爆药污染场地土壤中锑（Sb）进行稳定化处理,通过等温吸附实验、批量浸出实验、比表面积测定以及BCR分析,研究了铁、铝单一和混合吸附剂的稳定化效果以及稳定化前后土壤比表面积及Sb形态的变化.结果表明：不同铁基吸附剂对Sb的等温吸附符合Freundlich模型,FeSO₄ （log K_f= 5.85）的吸附能力明显高于Fe⁰ （log K_f = 3.21）和针铁矿（log K_f = 4.32）;稳定时间为10d的条件下,不同铁基吸附剂对Sb的稳定化效率随添加量的增大而提高,且10%FeSO₄（97.1%） > 10% Fe⁰（72.3%） > 针铁矿（41.0%）;FeSO₄的添加明显促进了土壤中Zn、Cu、Pb的浸出,达到原土壤浸出浓度的1990.2、2.8倍和21.6倍,添加Al（OH）₃后能够显著降低Zn、Cu、Pb的浸出浓度,添加量为4%时,稳定化效率分别达到93.8%（Zn）、93.5%（Cu）和98.3%（Pb）;5%FeSO₄和4% Al（OH）₃混合吸附剂对Sb及Zn、Cu、Pb的综合稳定化效率最好,处理10d后稳定化效率最高可达94.6%、74.2%、82.2%和97.6%;进一步分析表明,混合吸附剂添加后比表面积能够达到原土壤的1.31~1.67倍,残渣态Sb比例增加0.037~0.197倍,与稳定化效果相一致,表明铁铝混合吸附剂是处理起爆药污染场地复合重金属污染土壤的有效途径.     

S-NZVI/PS凝胶反应带修复硝基苯污染地下水

采用前置硫化法合成制备硫化纳米铁,研究其与过硫酸盐对硝基苯的联合降解效果,检测反应前后溶液中铁离子和TOC浓度变化,对反应前后的S-NZVI进行表征,分析S-NZVI和PS对NB的联合降解机制.以纳米硅胶溶液为胶结剂,以PS为活性成分,制备缓释PS溶胶,注入砂柱中扩散形成凝胶,与S-NZVI构成S-NZVI/PS组合反应带,研究其对模拟硝基苯污染地下水的原位修复效果.结果表明,S-NZVI能够高效去除NB并生成大量苯胺（AN）,S-NZVI被PS氧化产生的Fe²⁺与PS组成活化过硫酸盐,对AN具有较好的降解和矿化效果.当NB浓度为100mg/L、S-NZVI和PS的投加量分别为0.5,2.5g/L时,NB去除率达91%,AN出水浓度为1.96mg/L,TOC去除率达64.09%.反应后S-NZVI的主要铁氧化产物为Fe₃O₄和FeO（OH）.反应带实验结果表明,S-NZVI/PS组合反应带可有效去除地下水的NB并高效消减NB还原产生的AN,当进水中NB浓度为100mg/L,流量为0.4mL/min,注入S-NZVI含量为1200mg/L的浆液200mL,二氧化硅含量为30%、PS含量为12.5%的PS凝胶4.8g时,S-NZVI/PS组合反应带7d内对AN的去除率最高达97.6%,NB当量累计去除率为83.7%.     

A.ferrooxidans对高硫煤矸石去除酸性水体中Cr(VI)的强化作用

本研究考察了Acidithiobacillus ferrooxidans（A.ferrooxidans）联合高硫煤矸石（富含FeS₂）对模拟煤矿酸性水体中Cr（VI）的去除效果.结果表明,处理Cr（VI）初始浓度为50mg/L的模拟煤矿酸性废水（pH=2.5）时,投配率为6.67~33.33g/L高硫煤矸石可使Cr（VI）去除达到良好效果.50mg/LCr（VI）在24h内即可完全被高硫煤矸石中的FeS₂还原成Cr（III）,且在反应终点时（120h）,6.67,13.33,33.33g/L高硫煤矸石对还原产物Cr（III）的吸附去除率分别为7.1%、20.2%、29.1%.然而,在高硫煤矸石的还原和吸附作用下,大部分的Cr仍以Cr（III）形式残留在酸性水体中,且高硫煤矸石的大量投加也给水体带来了Fe²⁺、Fe³⁺、SO₄^2-等二次污染物.在高硫煤矸石-Cr（VI）体系中引入A.ferrooxidans和9K培养基后,A.ferrooxidans介导的Fe²⁺生物氧化及产物Fe³⁺水解矿化过程可促进部分Fe²⁺、Fe³⁺、SO₄^2-等向次生铁矿物（包括施氏矿物和黄钾铁矾）转变,从而使模拟酸性水体中残留的Cr（III）通过次生铁矿物的吸附或共沉淀作用被清除.在A.ferrooxidans强化作用下,模拟煤矿酸性废水中Cr（VI）在96h即可达到99.4%的去除率.     

Novel synthesis of aluminum hydroxide gel-coated nano zero-valent iron and studies of its activity in flocculation-enhanced removal of tetracycline

A newly designed aluminum hydroxide gel-coated nanoscale zero-valent iron(AHG@NZVI)with enhanced activity and dispersibility of NZVI was successfully synthesized.The AHG@NZVI composite was synthesized via control of the surface AHG content.AHG@NZVI-1,AHG@NZVI-2 and AHG@NZVI-3 were prepared under centrifugal mixing speeds of 1000,2000 and 4000 r/min,respectively.The activity of AHG@NZVI was evaluated by its tetracycline(TC) removal efficiency.The effects of AHG content,pH value,reaction temperature,and presence of competitive anions on TC removal were investigated.TC could be removed by both adsorption and chemical reduction on AHG@NZVI-2(centrifugal speed 2000 r/min) in a short time with high removal efficiency(≥98.1%) at the optimal conditions.Such excellent performance can be attributed to a synergistic interaction between aluminum hydroxide gel and NZVI:(1) AHG could enhance the stability and dispersity of NZVI;(2) aluminum hydroxide gel could absorb a certain amount of TC and Fe~(2+)/Fe~(3+),which facilitated the mass transfer of TC onto the NZVI surface,resulting in acceleration of the reduction rate of TC by the AHG@NZVI composite;and(3) AHG-Fe~(2+)/Fe~(3+)could absorb a certain amount of TC by flocculation.The kinetics of TC removal by AHG@NZVI composite was found to follow a two-parameter pseudo-first-order model.The presence of competitive anions slightly inhibited the activity of AHG@NZVI systems for TC removal.Overall,this study provides a promising alternative material and environmental pollution management option for antibiotic wastewater treatment.