铁/铝复合氧化物对氟离子的吸附

水体中氟离子超标严重危害人们的健康,为了寻求廉价、高效的氟离子吸附剂,本文通过共沉淀-焙烧的方法制备了铁铝复合金属氧化物吸附剂,并将之应用于氟离子废水的吸附。探讨了氧化物配比、吸附时间、吸附剂投加量、溶液初始浓度、溶液p H等因素对氟离子吸附效果的影响。结果表明:当铁铝复合氧化物中铁氧化物与铝氧化物摩尔比为1∶2,氟离子溶液初始浓度100 mg/L,固液比为4 g/L,溶液p H为6.0,吸附时间为30 min时,该吸附剂对氟离子的吸附效果最佳,此时氟离子的去除率为92.5%。     

矿石黏土类物质、铁锆化合物对磷吸附影响因素研究进展

介绍了水中含磷的危害及通过比较选择吸附法作为一种高效、低能耗的除磷方法,吸附剂及其特点和金属类氧化物、黏土矿石类、活性炭吸附材料的吸附原理。详细阐述了反应温度、反应时间、反应pH值、共存离子对矿石黏土类物质和铁锆化合物吸磷过程的影响:反应温度主要通过影响分子热运动从而影响到吸附材料吸磷效果;对任何吸附材料吸磷都需要一定的反应时间来达到最佳效果;反应pH值主要通过影响溶液中离子浓度、种类及吸附材料表面所含的离子与其反应从而影响到吸附材料吸磷效果;共存离子的存在可能会提高库仑力和磷酸盐活性部位竞争力。同时也阐述了吸附剂用量、磷的初始浓度、电解质、吸附材料粒径对吸磷效果的影响。今后对吸附磷材料的研究应重点关注改性材料及复合材料。     

蛇纹石-黏土复合颗粒除氟的动态实验研究

为研究蛇纹石-黏土复合颗粒的除氟性能,采用室内动态实验探讨了复合颗粒在不同氟离子浓度、不同吸附柱高度和不同流速下对含氟水除氟效果的影响及其吸附动力学过程.试验结果表明:吸附剂的动态吸附容量与吸附剂高度、原水氟离子浓度呈正相关,而与进水流速呈负相关;吸附剂传质区长度与进水流速、吸附剂高度及原水氟离子浓度均呈正相关.吸附动力学拟合结果显示:蛇纹石-黏土复合颗粒对水中氟的吸附动力学符合Yoon and Nelson方程,平衡吸附容量与吸附剂高度呈正相关,与进水流速呈负相关.随着初始氟离子浓度的增加,到达吸附平衡时间缩短,吸附容量逐渐增大.     

新型功能化改性生物质吸附剂的制备及其对重金属铜的吸附性能研究

为有效解决自然水体中重金属污染的问题,以来源广泛、成本低廉、可再生的废弃生物质材料(花生壳、玉米芯、白果壳、树皮等)为基体,通过表面预处理、高温炭化以及后功能化改性(包括硫酸、硝酸、柠檬酸、高锰酸钾活化)等工艺制备了一系列高效多孔生物吸附剂材料。结果表明,经过高锰酸钾氧化改性的生物吸附剂(花生壳、玉米芯、白果壳、树皮)对重金属铜的吸附率最高,分别达到79.4%、65.3%、83.9%、71.8%,与原始生物材料吸附效果相比,吸附容量显著提高了66.2%、53.7%、70.7%、53.1%。同时,优化了高锰酸钾改性吸附剂对铜的吸附条件(时间、温度、pH)。经过结构特性表征分析,改性后的吸附剂相较于改性之前生物材料比表面积更大、孔隙结构更多,较大幅度提升了对于重金属离子的吸附能力。该研究所开发的高效生物质吸附剂为环境中重金属离子的消除以及资源化利用提供了一种廉价高效的新方法、新思路,同时也提供了一种绿色高效处理农林业废弃物的途径。     

人工湿地填料除砷效率及影响因素试验研究

人工湿地是净化含砷水体的重要途径之一,而填料是决定人工湿地除砷效果的关键因素。通过填料如砾石、锰砂、沸石和陶粒的理化性质的测定,以及各种填料的吸附动力学、吸附等温线和吸附影响因素试验,研究了填料的除砷性能及影响因素。结果表明:4种填料均能在24 h内达到吸附平衡,一级动力学方程和二级动力学方程能很好地拟合其吸附过程;锰砂、陶粒、沸石和砾石最大吸附容量依次为36.62,25.39,11.96,7.04 mg/kg,Freundlich方程能较好地拟合填料的等温吸附过程;在0.25~0.50 mm范围内,粒径对锰砂和陶粒吸附砷影响不显著;溶液中氨氮浓度在0.50~2.50 mg/L范围内几乎不影响填料对砷的吸附;当砷初始浓度低于0.4 mg/L时,磷酸盐在0.25~0.50 mg/L范围内对填料吸附砷的影响不显著;砷初始浓度高于0.4 mg/L时,随着磷酸盐浓度从0.25 mg/L增加至0.50 mg/L时,陶粒对砷的最大吸附量降低了2.57 mg/kg,对锰砂的吸附量降低了1.85 mg/kg。     

纳米铁/活性炭新型材料的制备及其对铜离子的吸附性能研究

以活性炭为载体,采用沉淀法制备纳米铁/活性炭新型材料,对活性炭的结构变化进行BET和TEM表征分析,研究纳米铁负载前后活性炭对水中铜离子的吸附能力以及p H值、起始浓度、吸附时间等因素对吸附性能的影响,同时考察其再生性能。结果表明:纳米铁成功负载于活性炭上,随着p H值的增加,吸附容量逐渐增大,当p H=6时,纳米铁/活性炭的最大吸附量为18.73 mg/g,与活性炭相比提高了150%。新型材料对铜离子的吸附过程符合Langmuir和Freundlich吸附模型,对铜离子的吸附量随时间变化的规律符合准二级动力学模型,由于负载的纳米铁阻碍了铜离子向材料表面扩散,其吸附速率仅为0.002 g/(mg·min),与活性炭相比下降了60%左右。新型材料再生效率高,具有较好的应用前景。     

石英砂负载氧化铁吸附除磷的研究

通过小试摇床试验研究了石英砂负载氧化铁(IOCS)在不同的试验条件下(pH、吸附时间、背景离子等)对磷的吸附效果.结果表明:在中性条件下,IOCS吸附除磷效果最佳;锑与磷在IOCS上产生明显的竞争吸附.准二级反应动力学模型及Langmuir等温吸附模型可分别较好地描述磷的吸附动力学及吸附等温线试验结果;再生试验表明:采用0.1 mol/L的NaOH溶液可以使得IOCS再生,且再生次数对吸附容量影响不大.     

高锰地下水吸附试验研究

采用颗粒活性炭、粉末活性炭和活性炭负载壳聚糖对高锰地下水进行静态吸附试验,利用颗粒活性炭进行动态吸附试验,研究了静态条件吸附剂投加量、pH值、温度对吸附效果的影响,以及动态条件下浓度和流速对吸附效果的影响。结果表明,三种吸附剂吸附效果相差不大,相对而言粉末活性炭效果最好,颗粒活性炭效果与粉末活性炭较接近;静态试验中,当水中Mn2+的浓度为5mg/L时,水温25℃,pH值为6.8～7.0状态下颗粒活性碳的处理效果最好,最佳投加量为0.02g/L,即0.4g(GAC)/mg(Mn2+);动态条件下,锰离子浓度的增加、流速增大都会使初始穿透点提前。     

改性粉煤灰对含 Cr（Ⅵ）废水的处理效果研究

研究了氧化钙改性粉煤灰对水中Cr （Ⅵ）的吸附效果,结果表明：氧化钙改性粉煤灰吸附含Cr（Ⅵ）废水中的Cr（Ⅵ）符合Freundlich吸附等温模型,为自发的熵减吸附;其吸附行为符合拟二级动力学方程,吸附过程的活化能为-18.609 kJ/mol ,以物理吸附为主;通过T homas模型模拟了粉煤灰柱吸附行为,计算得到粉煤灰理论吸附容量为0.4367 m g/g。     

改性沸石吸附水中铬(Ⅵ)的试验研究

采用氯化铁改性后的沸石对溶液中的铬(Ⅵ)进行静态吸附试验,研究了溶液pH值吸附时间、吸附剂用量、铬(Ⅵ)初始浓度等因素对吸附的影响.结果表明,改性沸石吸附铬(Ⅵ)的速度比天然沸石快,1h内可达到吸附平衡;溶液pH值在偏酸性时更有利于吸附进行;用Langmuir方程拟合了吸附等温线(R=0.9999),可用二级动力学方程描述吸附动力学过程,实验条件下计算的最大吸附量为1.18mg/g.     

改性生物炭的光谱表征及砷的吸附效果研究

为了研究棉花秸秆生物炭的基本性质及其对砷的吸附效果,采用FeCl₃·6H₂O改性棉花秸秆生物炭,通过XRD、FT-IR和SEM等技术表征其光谱性能,并探究其对砷的吸附效果。结果表明：采用FeCl₃·6H₂O改性棉花秸秆生物炭后,生物炭的pH值、比表面积以及C、N、H元素的含量和C/N的比值随Fe含量的提高显著降低,灰分和O元素的含量以及H/C、O/C和(N+O)/C的比值随Fe含量的提高显著增加,生物炭表层Fe₂O₃和Fe₃O₄的含量增加。生物炭改性后缩短了吸附砷的平衡时间,吸附率高达73.4%,远高于未改性生物炭的吸附率（44.7%）,吸附量高达7.63 mg/g,远高于未改性生物炭的吸附量（4.33 mg/g）,且随Fe含量的提高,吸附率和吸附量均显著增加。其作用机制主要是通过改性生物炭静电吸附能力、离子交换和Fe3+的还原作用降低水溶液中的As的含量,进而达到去除水溶液中As的目的。     

河北省清河县高氟地下水处理的试验研究

针对河北省清河县高氟地下水的高p H值（8.3）、高氟浓度（3.6 mg/L）的水质特点,以新型高效Fe-Al-Ce除氟吸附剂为核心,设计了含预处理、活性炭吸附和超滤单元的小型吸附装置用于家庭终端高氟水的处理。在清河高氟原水现场,对不同空间流速（SV）和不同运行方式条件下的Fe-Al-Ce吸附剂除氟性能和装置出水安全性进行了研究评价。结果表明,在SV=1 h-1条件下,装置运行效果良好,Fe-Al-Ce吸附剂除氟穿透吸附容量为活性氧化铝的3倍以上,装置出水的金属浓度符合标准要求,超滤单元对微生物有截留作用,但其微生物安全性还需进一步提高。     

Arsenic removal from groundwater by a newly developed adsorbent.

A novel adsorbent, which had been developed for phosphate adsorption, was adopted for arsenic removal from groundwater. Adsorption isotherm, pH dependence of the isotherm and adsorption rate were studied by batch method. Furthermore, by using a granular adsorbent of 1.8 mm diameter which is commercially available, lab-scale experiments of continuous adsorption treatment of actual groundwater containing arsenic at 50 mg m(-3) were conducted to examine the performance of the adsorbent. A large amount of arsenic, i.e., 10 g As kg(-1), was adsorbed at pH 7.0 and 10 mg As m(-3) in equilibrium concentration. It was only a 5% higher amount compared to conventional activated alumina. However, twice the bed volume, i.e., total volume of effluent divided by empty column volume, was achieved till breakthrough by using this novel adsorbent. This may be because the pH decrease, which enlarges apparent adsorption capacity of the adsorbent, is caused by a self-pH decrease function of the adsorbent. The self-pH decrease function must be delivered by dissociation of Al (III) aquoion. The proton release was clearly observed in batch experiments.     

煤质活性炭对Cr(Ⅵ)和As(Ⅲ)的吸附及其影响因素

以煤质活性炭(CAC)为吸附剂,吸附水溶液中Cr(Ⅵ)和As(Ⅲ)。研究了pH值、温度、吸附时间和活性炭投加量等因素对活性炭去除Cr(Ⅵ)和As(Ⅲ)效果的影响。结果表明,Cr(Ⅵ)和As(Ⅲ)最佳吸附的pH值分别为2和5,且pH值对吸附率的影响较大。Cr(Ⅵ)的吸附受温度影响较大,当温度从20℃增加到40℃,吸附率由70%提高到了95%;As(Ⅲ)的吸附随温度的升高先增加后减少,其最佳吸附温度为30℃。Langmuir吸附等温式能够很好地拟合Cr(Ⅵ)和As(Ⅲ)的实验数据,而Pseudo second order模型则较好描述了Cr(Ⅵ)和As(Ⅲ)的吸附动力学。Cr(Ⅵ)和As(Ⅲ)吸附的热力学研究表明,该吸附是一个自发进行的自然吸热过程。     

Effect of Fe3O4 nanoparticles on magnetic xerogel composites for enhanced removal of fluoride and arsenic from aqueous solution

Fe₃O₄ magnetic xerogel composites were prepared by polycondensation of resorcinol (R)–formaldehyde reaction via a sol–gel process in an aqueous solution through varying the molar ratio of Fe₃O₄ nanoparticles (MNPs), catalyst (C), and water (W) content. MNPs were obtained by co-precipitation (MC), oxidation of iron salts (MO), or solvothermal synthesis (MS). Both MNPs and magnetic xerogels were examined regarding the performance of arsenic and fluoride removal in a batch system. The MC-based MNPs had higher adsorption capacities for both fluoride (202.9 mg/g) and arsenic (3.2 mg/g) than other MNPs in optimum conditions. The X-ray diffraction, Fourier transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy confirmed that Fe was composed into the polymeric matrix of magnetic xerogels that contained 0.59%–4.42% of Fe with a molar ratio of MNPs (M) to R between 0.01 and 0.10. With low R/C and optimum M/R ratios, an increase in the surface area of magnetic xerogels affected the fluoride and arsenic adsorption capacities. The magnetic xerogel composites with the MC-based MNPs prepared at a fixed R/C ratio (100) and at different R/W (0.05–0.06) and M/R (0.07–0.10) ratios had a high arsenic removal efficiency of 100% at an As(V) concentration of 0.1 mg/L and pH of 3.0. The maximum adsorption capacities of magnetic xerogels were approximately five times higher than those of the xerogels without MNP composites. Therefore, Fe₃O₄ nanoparticles enhanced the adsorption of arsenate and fluoride. The variations of alkaline catalyst and water content significantly affected the resulting properties of textural and surface chemistry of magnetic xerogel composites.     

Four years of development and field-testing of IHE arsenic removal family filter in rural Bangladesh

UNESCO-IHE has been developing an arsenic removal family filter with a capacity of 100 L/day based on arsenic adsorption onto iron oxide coated sand, a by-product of iron removal plants. The longer term and field conditions performance of the third generation of eleven family filters prototypes were tested in rural Bangladesh for 30 months. All filters achieved initially highly effective arsenic removal irrespective of arsenic concentration and groundwater composition. Arsenic level in filtrate reached 10 mug/l after 50 days of operation at one testing site and after 18 months of continuous operation at other 3 testing sites. Arsenic level at other 7 sites remained below the WHO guideline value till the end of study. Positive correlation was found between arsenic removal capacity of the filter and iron concentration in groundwater. In addition to arsenic, iron present in groundwater at all testing sites was also removed highly effectively. Manganese removal with IHE family filter was effective only when treating groundwater with low ammonia. A simple polishing sand filter, after IHE family filter, resulted in consistent and effective removal of manganese. IHE family filters were easy to operate and were well accepted by the local population.     

吸附法去除饮用水中砷的研究进展

介绍砷的分布以及饮用水中砷超标的危害,综述当前国内外用不同吸附方法去除饮用水中砷的研究进展,分析其吸附性能和特点。结果表明,在归纳的6种吸附除砷方法中,复合材料与改性材料除砷效率高,处理费用低,目前最具有市场应用前景;活性材料的吸附效果受pH值控制;含铁矿物材料在除砷过程中易导致二次污染;纳米材料除砷效率最高,应是今后的主要发展方向。     

Comparative evaluation of As, Se and V removal technologies for the treatment of oil refinery wastewater

In this study, a broad range of readily deployable metal removal technologies were tested on a US refinery's wastewater to determine vanadium, arsenic and selenium removal performance. The bench-scale treatability studies were designed and performed so that test conditions could be as uniform as possible given the different mechanisms of action and engineering applications of each technology. The experimental data show that both ferric precipitation and reactive filtration were able to remove As, Se and V more efficiently from the wastewater than other tested technologies. Additionally, granular ferric hydroxide (GFH) adsorption was also effective in both V and As removal. Although the thiol-SAMMS adsorbent was developed for mercury removal, it also demonstrated appreciable selenium removal. None of the tested membrane filtration technologies showed any significant metals removal. This was attributed to the dissolved form of the metals as well as the wastewater's fouling characteristics.     

废弃硅藻土制备MCM-41介孔分子筛的表征及吸附性能研究

以废弃硅藻土作为硅源,CTAB为模板剂,通过水热法合成介孔材料MCM-41,并使用X-射线荧光分析仪(XRF),X-射线粉末衍射仪(XRD),氮气等温吸附/脱附仪,傅利叶红外线吸收光谱仪(FT-IR),热重量分析仪(TGA),扫描式电子显微镜结合X射线能量色散谱(SEM-EDS)和高分辨率穿透式电子显微镜分析(HRTEM)等方式进行表征;通过吸附重金属离子实验检测该材料的性能。结果表明:所合成的材料为介孔结构,孔道排列较为整齐,MCM-41的比表面积为1 060.2 cm2/g,平均孔洞体积约为1.05 cm3/g,孔径为3.95 nm,孔径分布窄,对重金属Cu2+有很好的吸附性能。本研究对废弃硅藻土的综合利用及重金属的治理具有一定的参考价值。     

地下水砷污染防治试验研究

针对我国地下水砷污染及饮用水质健康风险问题,以地下水中砷这种特征污染物的净化及安全供水为研究目标,为了寻求治理地下水砷污染途径,提出了石英砂原位改性除砷的方法。采用化学沉淀法制备改性石英砂,在室内开展镀铁条件试验研究,确定注入试剂种类、注入方式、持续时间及强度等重要参数。进而,对改性石英砂进行了表面特征分析并开展了静态吸附试验和动态除砷试验。研究成果旨在为我国地下水污染控制和饮用水安全供给工程提供相关的技术支撑。