萃取净化废水中镉的动力学研究简

采用恒界面池研究了二壬基萘磺酸（简称DNNSA或HD）-煤油体系萃取废水中镉离子的动力学。考察了搅拌转速、二壬基萘磺酸浓度、镉离子浓度和温度对萃取速率的影响,并得到了DNNSA萃取废水中镉离子的萃取动力学方程。实验结果表明,镉离子的萃取速率在200 r/min时出现与搅拌强度无关的化学反应动力学“坪区”,FT-IR结果表明,反应产物为磺酸盐;在动力学“坪区”,镉离子萃取速率随着萃取剂浓度、水相中的镉离子浓度增加而增加;随着温度升高,萃取速率增加,萃取活化能为11.8 kJ/mol。     

生物柴油萃取高浓度吡啶废水

农药、医药等行业的生产过程中产生含有高浓度吡啶的废水,采用溶剂萃取法萃取废水中的吡啶既可改善废水的可生化性,又可实现吡啶的循环利用.实验以生物柴油为萃取剂,讨论了体系的pH值、温度、相比及时间等条件对萃取分配系数(D)及吡啶去除率的影响.结果表明,较为适宜吡啶萃取的条件是:萃取时间为30 min,pH值为6,温度为30℃,相比为1:1.在上述萃取条件下,生物柴油与吡啶水溶液进行六级错流萃取后,水中吡啶浓度从15%降至0.84%,吡啶去除率达到94.40%.     

超声萃取法处理含油污泥

应用超声强化技术,对以汽油为萃取剂的超声萃取法处理含油污泥的工艺进行了研究,筛选了调整剂、絮凝剂、破乳剂,探讨了萃取温度、萃取时间、超声频率、超声功率等对处理效果的影响。结果表明:在调整剂为采油废水、物料配比为v(萃取剂)∶v(调整剂)∶v(油污泥)=4∶4∶1的条件下,萃取工艺为萃取温度40℃、萃取时间15 min、超声频率40kHz、超声功率150 W时,可回收含油污泥中83.7%的油品。     

基于响应曲面法的聚合氯化铝对矿井废水中氟离子混凝去除工艺优化

为有效去除矿井废水中氟离子,利用聚合氯化铝(PAC)对某矿井含氟废水进行混凝效果研究,设计单因素实验,研究了铝氟摩尔比(r)、pH和凝聚时间等因素对PAC混凝去除氟离子的影响,依据响应曲面法的Box-Behnken Design(BBD)实验设计原理,探究了r、pH和凝聚时间对混凝效果的影响,并优化工艺参数。结果表明：各因素对混凝效果的影响顺序为r> pH>凝聚时间;在r=19.04、pH=6.5、凝聚时间为2.9 min的最佳条件下,氟离子的去除率为56.4%,与预测值(56.46%)基本吻合;去除氟离子的机理包括PAC对氟离子絮凝沉淀、离子交换和络合沉降等;pH影响PAC在溶液中的存在状态,凝聚时间则影响矾花在溶液中形成的速度以及密集程度,进而影响混凝沉淀效果。由此可以看出,BBD优化模型预测与实际处理效果基本一致,铝氟摩尔比和pH是去除氟离子的主要控制因素。本研究使用的实验方法具有处理工艺简单、效果稳定、成本低等优点,可为实际矿井废水中氟离子的去除提供参考。     

高分子空心微球的合成及其对废水镉微污染物的吸附性能

为考察高分子纳米微球对微污染物镉的吸附性能,以高分子空心微球为吸附剂,以废水镉微污染物为吸附对象,探讨高分子空心微球的重金属吸附性能,重点考察水热时间和水热温度对高分子微球表面基团的影响。结果表明:水热温度升高,高分子微球出现粘连;当水热温度为180℃,水热时间为4 h时,镉微污染物去除率最佳。强酸性条件有利于高分子微球吸附镉微污染物,当pH4时,镉微污染物去除率超过95%;而中碱性条件的去除率不超过70%。高分子空心微球镉离子吸附过程不属于放热过程,最大吸附量超过75 mg·g~(-1)。经盐酸再生利用时,高分子空心微球的镉吸附率没有出现下降,超过95%以上。高分子微球对微污染物镉具有良好的吸附性能。     

固相微萃取-气相色谱法测定饮用水及其水源水中的氯酚

利用固相微萃取(SPME)-气相色谱法(GC)联用技术测定饮用水及其水源水中的氯酚．优化萃取温度、萃取平衡时间、酸度、离子强度等实验条件．所建方法简便、精确,自来水和太湖水中均检测到氯酚。     

兰炭废水中酚类物质萃取及回收效果

为了去除并回收兰炭废水中的高浓度挥发酚类物质,实验研究了甲基异丁酮溶剂在不同条件下对兰炭废水中挥发酚的萃取及回收效果。结果表明,萃取时间为10 min,温度为35℃,p H低于8.0,萃取体积比(萃取剂体积/兰炭废水体积)在大于1∶5时,经过萃取后废水中挥发酚浓度由6 385 mg/L降至230 mg/L,去除率高达96.4%,有效减轻了后续生化处理的负担。而萃取剂经过蒸馏分离后,挥发酚的回收率可达95%以上,甲基异丁酮的损耗率为0.18%~0.2%。实验表明,甲基异丁酮是一种可以长期循环使用的工业萃取剂,显示了良好的应用前景。     

萃取技术分离工业废水中的苯胺

研究以硝基苯为萃取剂,25℃下通过盐析萃取法回收工业废水中苯胺。以静态分批实验考察了废水酸度、初始苯胺浓度、萃取剂与废水比(油水比)、萃取级数、无机盐种类(NaCl,KCl,Na2SO4,CaCl2,K2SO4)和浓度对苯胺萃取率的影响,获得了最佳操作工艺条件。实验结果表明,硝基苯盐析萃取技术可以有效回收废水中苯胺,且高pH和溶剂比有利于苯胺萃取,随着无机盐浓度的增加苯胺回收率增加。在适宜的条件下,通过盐析作用,经过五级萃取苯胺萃取率接近100%。     

十六烷基三甲基溴化铵改性生物炭对水中镉离子吸附性能的影响

针对水体重金属污染治理问题,通过十六烷基三甲基溴化铵(CTAB)对竹炭(BC)、椰壳炭(CSC)进行改性,采用傅里叶红外变换光谱(FT-IR)、扫描电镜(SEM)、X射线光电子能谱分析(XPS)和热稳定性分析(TGA)对改性前后的材料进行了表征,探究了投加量、pH对2种改性材料吸附去除水中镉离子性能的影响,并进行了动力学方程拟合及等温吸附模型拟合,探讨了CTAB改性前后活性炭吸附水中镉离子的机理。结果表明:2种CTAB改性材料基本结构虽未改变,但提升了竹炭(BC)和椰壳炭(CSC)的吸附性能,改性后材料的饱和吸附量分别为12.56 mg·g-1(CTAB-BC)、 10.71 mg·g-1 (CTAB-CSC),较改性前分别提高了111%和92%;同时,CTABBC、CTAB-CSC的吸附量受pH影响较大,对二者的最适pH分别为4～7、6～7;CTAB-BC、CTAB-CSC均能较好地拟合准二级动力学方程(R2CTAB-BC=0.999 9, R2CTAB-CSC=0.993 7)及Langmuir模型(R2CTAB-BC=0.970 3, R2CTAB-CSC=0.9768)。通过分析可知,CTAB-CSC、CTAB-BC 2种材料对含镉废水均有较好的去除效果。     

血粉对废水中镉离子的高效去除效应

以屠宰场废弃动物血液为原料,经高温干燥、粉碎为血粉,以此血粉为吸附剂,研究血粉添加量、溶液初始浓度、吸附温度、溶液pH、吸附时间对废水中Cd2+吸附量与去除率的影响。结果表明,在25℃、pH=5时,4 g血粉对初始浓度为20mg·L~(-1)的镉离子溶液(100 m L)振荡吸附2 h后,溶液中剩余镉离子浓度为0.1 mg·L~(-1),Cd2+的去除率为99.38%,达到污水综合排放标准(GB 8978-1996)中镉排放限值0.1 mg·L~(-1);血粉对镉离子的吸附反应符合Langmuir等温吸附方程,可决系数为0.999 7,Cd2+的理论饱和吸附量为10.24 mg·g-1。为了使剩余Cd2+浓度达到更低(电镀废水排放标准),在吸附工艺上设计出2步吸附法,即第1次吸附后的混合液进行过滤,再将滤液加1 g血粉进行第2次吸附。结果表明,2步吸附法大大降低了溶液中剩余Cd2+离子浓度,即经过第1步、第2步吸附后,溶液中剩余Cd2+离子浓度降至0.006 mg·L~(-1),达到或低于电镀污染物排放标准(GB 21900-2008)对Cd2+的排放限值(0.05 mg·L~(-1))。这是常规吸附剂活性炭、石英砂、高岭土等所不能达到的技术指标,为废水去除Cd2+提供了一种可能的新技术。     

蓖麻油衍生微乳液对菲的增溶和洗脱作用及其对菲污染土壤的修复机理

比较研究了蓖麻油硫酸盐(SCOS)与普通表面活性剂Triton X-100(TX100)、Tween 80(TW80)、Brij35、十二烷基苯磺酸钠(SDBS)和十二烷基硫酸钠(SDS)等对菲的增溶和洗脱作用.结果表明,菲表观溶解度与SCOS的浓度呈单一线性关系,SCOS微乳液对菲的增溶比SR=0.0314为最大,菲在微乳相和水相之间的分配系数logKem=4.44,大于菲在胶束相和水相之间的分配系数(logKmc).1:10土-水体系下,SCOS微乳液对菲污染土壤的清洗速率最快,清洗效率最高.SCOS有望成为土壤有机污染淋洗修复的增效试剂.     

Chromium (III) removal by supported liquid membranes: a comparison among D2HEPA, DNNSA, and a novel extractant as carriers.

A facilitated transport study in supported liquid membranes (SLM) using the extraction reagents di-2-ethylexilfosphoric acid (D2HEPA), dinonylnaftalene sulfuric acid (DNNSA), and a novel complexing agent, trimethyl cis,cis-1,3,5-tripropyl-1,3,5 cyclohexenetricarboxilic acid (TTCHTCA) as carriers has been carried out. Organic solvents with different dielectric constants as diluents have been used to obtain the highest extraction and transport values. The results obtained have shown that, by using different organic phases (carrier and/or diluent), SLMs with different ion flux and transport ability can be obtained. The carrier concentration in the membrane and the chromium (III) [Cr(III)] ions concentration in aqueous phase have been varied to see the effect on transport of Cr(III) ions across the membrane. For the carriers D2HEPA and TTCHTCA, the transport of Cr(IlI), both in batch and in recirculation operation mode, has been studied. Very good results in terms of flux and transport have been obtained using TTCHTCA.     

乳化液膜体系去除电解锰废水中的Mn2+

采用乳化液膜法处理电解锰废水,考察制乳条件和提取条件对去除效果的影响。研究结果表明最佳制乳条件为:4%(V/V)span-80做表面活性剂,3%二(2-乙基己基)磷酸酯做载体,柴油做膜溶剂,用NaOH调节内水相pH为12,制乳时间为10 min,油内比2∶1;最佳提取条件:外水相pH为6～7、乳水比1∶10、提取时间10 min。制得的乳化液膜对电解锰废水中的Mn2+去除率可高达99.99%,出水Mn2+浓度低于2mg/L,实现水质达标排放。     

高酚焦化废水萃取脱酚预处理

为了降低高酚焦化废水中挥发酚的浓度，实验研究了磷酸三丁酯煤油溶液在不同条件下对高酚焦化废水进行萃取脱酚预处理的效果。结果表明，萃取时间为8min，磷酸三丁酯煤油浓度为30％，温度低于40％，pH低于8．0，萃取比（油／水）R=1：2时，经过萃取后分水挥发酚浓度由4165mg降低到127．62mg／L，去除率高达96．94％，为后续生化处理奠定了基础。而萃取剂经过氢氧化钠溶液反萃取再生后，萃取剂的回收利用率可达94．25％以上。     

乳化液膜体系去除电解锰废水中的Mn~（2＋）

采用乳化液膜法处理电解锰废水,考察制乳条件和提取条件对去除效果的影响。研究结果表明最佳制乳条件为：4%（V/V）span-80做表面活性剂,3%二（2-乙基己基）磷酸酯做载体,柴油做膜溶剂,用NaOH调节内水相pH为12,制乳时间为10 min,油内比2∶1;最佳提取条件：外水相pH为6～7、乳水比1∶10、提取时间10 min。制得的乳化液膜对电解锰废水中的Mn2＋去除率可高达99.99%,出水Mn2＋浓度低于2mg/L,实现水质达标排放。     

聚硅基复合氯化铁絮凝剂的制备及其在采油废水处理中的应用

采用硅酸钠制备聚硅酸,探讨了活化pH、活化剂、硅酸钠浓度(以SiO_2质量分数计)及聚合温度等因素对聚硅酸稳定性的影响.利用聚硅酸及氯化铁制备聚硅基复合氯化铁(PSiF),并通过正交试验分析了活化pH、Si/Fe(摩尔比)、OH/Fe(摩尔比)、制备时间对PSiF絮凝性能的影响.综合考虑絮凝性能、稳定性以及经济性等因素,确定PSiF适宜的制备条件为SiO_2质量分数2%～3%;活化pH为2～3;Si/Fe为0.50～0.75;OH/Fe为0.50～0.75;制备时间为0.5 h;聚合温度低于25℃.对比PSiF、PAC、FeCl_3对采油废水的处理效果,PSiF除浊、除COD效果以及经济性最好,是一种应用前景广阔的新型絮凝剂.     

Removal of polycyclic aromatic hydrocarbons from aged-contaminated soil using cyclodextrins: experimental study

The removal of polycyclic aromatic hydrocarbons (PAHs) from soil using water as flushing agent is relatively ineffective due to their low aqueous solubility. However, addition of cyclodextrin (CD) in washing solutions has been shown to increase the removal efficiency several times. Herein are investigated the effectiveness of cyclodextrin to remove PAH occurring in industrially aged-contaminated soil. Beta-cyclodextrin (BCD), hydroxypropyl-beta-cyclodextrin (HPCD) and methyl-beta-cyclodextrin (MCD) solutions were used for soil flushing in column test to evaluate some influent parameters that can significantly increase the removal efficiency. The process parameters chosen were CD concentration, ratio of washing solution volume to soil weight, and temperature of washing solution. These parameters were found to have a significant and almost linear effect on PAH removal from the contaminated soil, except the temperature where no significant enhancement in PAH extraction was observed for temperature range from 5 to 35 degrees C. The PAHs extraction enhancement factor compared to water was about 200.     

一种新型环境矿物材料在废水治理中的应用研究--硅质磷块岩吸附水溶液中镉离子的研究

硅质磷块岩对水溶液中镉离子的吸附实验结果表明,硅质磷块岩对水溶性镉离子具有良好的去除效果,主要影响因素有介质的酸度、作用时间、镉离子的初始浓度和样品用量.在pH=6,作用时间为15 min,初始Cd2+浓度为30mg/L的实验条件下,硅质磷块岩对镉离子的去除率可达98%,有可能利用动态法进行工业废水的连续处理.初步研究结果显示,磷块岩对水溶性镉离子的吸附作用符合Langmuir等温吸附模型,不同产地的硅质磷块岩S1和S2对镉离子的最大吸附容量分别为4.43 mg/g和3.88 mg/g.     

Phytoremediation potential of Spirulina (Arthrospira) platensis: biosorption and toxicity studies of cadmium

This study examines the possibility of using Spirulina (Arthrospira) platensis TISTR 8217 to remove low concentrations of cadmium (less than 100 mg/l) from wastewater. The cyanobacteria were exposed to six different cadmium concentrations for 96 h, and the growth rate was determined using an optical density at 560 nm. The inhibiting concentration (IC50) was estimated using probit analysis. The IC50 at 24, 48, 72, and 96 h were 13.15, 16.68, 17.28, and 18.35 mg/l Cd, respectively. Cellular damage was studied under a light microscope and a transmission electron microscope. Swollen cells and fragmented filaments were observed. Cell injury increased with increasing concentrations of cadmium. Ultrastructural changes were observed in the algae exposed to cadmium concentrations both close to IC50 (14.68 mg/l) and at IC50 (18.35 mg/l). The alterations induced by cadmium were disintegration and disorganization of thylakoid membranes, presence of large intrathylakoidal space, increase of polyphosphate bodies, and cell lysis. In addition, the cadmium adsorption by algal cells was studied. Environmental factors were found to have an effect on biosorption. The uptake of cadmium was not affected by the temperature of the solution, but the sorption was pH dependent. The optimum pH for biosorption of algal cells was 7. The cadmium uptake process was rapid, with 78% of metal sorption completed within 5 min. The sorption data fit well to the Langmuir isotherm. The maximum adsorption capacity for S. platensis was 98.04 mg Cd per g biomass.     

Eichhornia crassipes capability to remove naphthalene from wastewater in the absence of bacteria

The aim of the current study was to investigate the potential of an aquatic plant, the water hyacinth (Eichhornia crassipes) devoid rhizospheric bacteria, to reduce naphthalene (a polyaromatic hydrocarbon) present in wastewater and wetlands.The capability of sterile water hyacinth plants to remove naphthalene from water and wastewater was studied in batch systems. Water hyacinths enhance the removal of pollutants through their consumption as nutrients and also through microbial activity of their rhizospheric bacteria.Experimental kinetics of naphthalene removal by water hyacinth coupled with natural rhizospheric bacteria was 100% after 9 d. Plants, decoupled of rhizospheric bacteria, reduced naphthalene concentration up to 45% during 7 d. Additionally, naphthalene uptake by water hyacinth revealed a biphasic behavior: a rapid first phase completed after 2.5 h, and a second, considerably slower rate, phase (2.5-225 h). In conclusion, water hyacinth devoid rhizospheric bacteria reduced significantly naphthalene concentration in water, revealing a considerable plant contribution in the biodegradation process of this pollutant.