金属基吸附剂去除水体中磷酸盐的研究进展

磷是生命组成必不可少的元素,同时也是导致水体富营养化的主要限制因子之一.目前,磷在地球上的流失率极高,过量的磷进入水体导致水体富营养化的形势日益加剧,迫切需要一种技术高效去除水体中的磷.吸附法由于操作简单、价格低廉,在过去20年里展现出优异的除磷性能,且其中金属基吸附剂尤其是基于锆(Zr)、镧(La)的金属的吸附剂已成...     

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。     

农业废弃物去除水体中磷的研究综述

磷是引起水体富营养化、藻类爆发的主要控制因素,从水中去除磷是控制水体富营养化的一项重要举措。本文综述了用农业废弃物作为吸附剂去除水体中磷的研究进展。研究发现为提高磷的去除效率,需要对农业废弃物进行改性。吸附剂不同和改性方法不同,吸附机理和影响吸附效率的因素也不同。采用农业废弃物去除水中的磷具有成本低、吸附材料易得、去除效率高、能对磷进行回收、不会对环境产生影响等优点。     

含铁矿物吸附剂除磷机理研究及中试应用

研究了含铁矿物吸附剂吸附含磷废水的各项性能,通过静态试验得出此吸附剂的最佳吸附条件,并以此为依据进行了动态小试试验和中试试验。结果表明,含铁矿物吸附剂的吸附平衡时间为45h,吸附等温线较符合Freundlich方程,pH约为5时吸附量达到最大,除铁离子和铝离子外,水体中无机阴离子和阳离子对磷酸盐的吸附影响不大。用1mol/L的NaOH溶液对饱和吸附剂解吸再生,解吸率达到90%以上。在合适的填充体积和进水流速下,含铁矿物吸附剂连续吸附除磷可以达到良好的效果,中试试验装置连续运行了约105d,出水TP达到了《地表水环境质量标准》(GB3838—2002)(Ⅲ类湖、库)要求。     

载锆活性炭在处置富营养污染水源中的应用研究

我国众多河流出现水体富营养化问题,导致河流水生态失衡,严重威胁水环境安全.本文提出一种利用氧氯化锆制备载锆活性炭吸附剂的新型水体除磷方法,并基于室内试验验证了该方法的可行性和高效性.研究发现载锆活性炭吸附剂对水体中磷元素的最大吸附量为2.25mg/g,对应pH值为2-3之间.载锆活性炭吸附剂的回收利用价值较高,在5％氢氧化钠溶液种脱附率可达93.15％.研究成果为解决我国河流水体富营养化问题提供了一定的指导作用.     

湖泊底泥中磷的形态分布分析

目前自然水体富营养化程度越来越严重,其底泥中磷的含量也与日俱增。不同形态分布的磷在自然情况变化时表现出不同的特性,底泥中磷的形态分布对于控制水体中磷的浓度有着重要影响。本研究以五步化学分级提取法测定了12个湖泊底泥中磷的形态分布。结果表明：在底泥中与钙结合的磷较多,平均占总量的60％左右。射线衍射结果也表明12个样品中均含有较高比例的晶体钙矿物,平均含量约为49％。除了与钙结合的磷之外,其余的磷多数与铁、锰化合物相结合,其含量平均占总数的18％。黏土矿物及铝氧化物中结合的磷占总量的8％,与残余磷9％相当。松散吸附结合态的磷含量最低约占6％。研究磷的形态分布分析方法对于了解底泥中磷的形态分布以及磷在水体一底泥中的迁移转化规律有着重要意义。     

新型铁碳微电解材料对水体磷的净化效果

传统铁碳微电解填料在除磷过程中出现的填料板结、沟流等问题不但会导致水体除磷效果降低,而且填料上脱落的碳颗粒导致产泥量增大还会增加后续处理成本。为此,采用铁基材料和碳纤维组成的新型铁碳微电解材料为除磷材料,以碳纤维、铁基材料等除磷材料为对照,考察了新型铁碳微电解材料对武汉市某湖泊水体总磷的去除效果及不同处理时间对水体总铁浓度和浊度的影响。结果表明:间歇曝气处理10 h,新型铁碳微电解材料、铁基材料和碳纤维对水体磷的去除率分别为80.00%、76.73%、2.86%;铁碳微电解处理72 h后静置96 h,水体总磷浓度从静置前的0.052 mg/L降至0.012 mg/L,水体总磷达《地表水环境质量标准》(GB 3838—2002)Ⅱ类标准,水体浊度和水体总铁浓度均变化不明显,最终分别为4.14 NTU和0.089 mg/L;悬挂于水体中的新型铁碳微电解材料未出现填料板结、沟流等现象,且水处理过程中仅产生铁絮凝物,克服了传统铁碳填料中因碳颗粒脱落导致产泥量增大等问题,提高了水体磷的去除率,而且水体浊度和总铁浓度增加不明显。研究成果有助于探寻水体富营养化治理的新途径。     

富营养化湖塘底泥氮磷吸附—解吸模拟研究

当外源营养盐负荷得到控制后,水体底泥中氮、磷等营养物质的释放成为诱发水体富营养化的重要内因。通过室内实验模拟富营养化湖塘底泥中氮、磷的吸附与解吸过程,对比分析不同氮、磷浓度条件下,上覆水—底泥间氮、磷吸附与解吸过程中的特点,探讨了影响氮、磷吸附和解吸关键因素,揭示了底泥氮、磷吸附和解吸平衡质量浓度,为制定科学的底泥内源氮、磷的控制措施提供科学依据。     

湖库富营养化水体移动式水质净化平台关键技术构建研究

为原位治理湖库等封闭水域的富营养化水体,提出了一种移动式水质净化平台治理新技术。移动式水质净化平台由水质净化单元(吸附单元、微孔曝气单元和微电流电解单元)、指令控制单元、水质在线检测单元和动力推进单元等组成。平台在水中移动过程中,通过微孔曝气单元和吸附单元的脱氮除磷,微电流电解抑藻来实现水体中过量营养盐削减和有害藻类防控的双重目的。针对移动式水质净化平台各单元功能要求,利用优选的吸附材料、曝气方式和电极材料,通过移动条件下的吸附、微孔曝气和微电流电解实验研究,获得最佳的吸附材料用量、原位吸附时间、曝气强度、电流密度、电解时间等技术参数。最后,根据实验结果,对进一步提高移动式水质净化平台的效率、平台运行管理等方面进行展望。移动式水质净化平台是一种富营养化水体治理的新技术,有望为富营养化水体营养盐削减和藻类水华防治提供新的解决方案。     

改性粉煤灰处理含磷生活污水试验

为了防止水体富营养化和有效处理生活污水,以改性粉煤灰为吸附剂,对含磷生活污水进行吸附脱磷试验,并研究粉煤灰粒径、投加量、pH值、温度、振荡强度以及吸附时间等因素对脱磷效果的影响。结果表明:在粉煤灰粒径为160~200目、投加量为25 g/L、溶液pH值为3.5、水温为50℃的条件下,对磷质量浓度为6.8 mg/L的生活污水,以140 r/min的强度振荡吸附150 min,磷的去除率可高达95.3%,水样中的磷质量浓度降至0.5 mg/L以下。     

Characteristics of phosphorus adsorption by sediment mineral matrices with different particle sizes

The particle size of sediment is one of the main factors that influence the phosphorus physical adsorption on sediment. In order to eliminate the effect of other components of sediment on the phosphorus physical adsorption the sediment mineral matrices were obtained by removing inorganic matter metal oxides, and organic matter from natural sediments, which were collected from the Nantong reach of the Yangtze River. The results show that an exponential relationship exists between the median particle size (D₅₀) and specific surface area (S_g) of the sediment mineral matrices, and the fine sediment mineral matrix sample has a larger specific surface area and pore volume than the coarse sediment particles. The kinetic equations were used to describe the phosphorus adsorption process of the sediment mineral matrices, including the Elovich equation, quasi-first-order adsorption kinetic equation, and quasi-second-order adsorption kinetic equation. The results show that the quasi-second-order adsorption kinetic equation has the best fitting effect. Using the mass conservation and Langmuir adsorption kinetic equations, a formula was deduced to calculate the equilibrium adsorption capacity of the sediment mineral matrices. The results of this study show that the phosphorus adsorption capacity decreases with the increase of D₅₀, indicating that the specific surface area and pore volume are the main factors in determining the phosphorus adsorption capacity of the sediment mineral matrices. This study will help understand the important role of sediment in the transformation of phosphorus in aquatic environments.     

混凝—吸附联用工艺去除水中磷的中试研究

为控制富营养化,上海某在建大型景观湖总磷(TP)控制限值为0.02 mg/L。为达到处理要求,在项目现场进行了中试,对化学混凝和吸附联用工艺去除水中的磷的效果进行了研究。中试结果表明:在合理的加药量条件下,化学混凝可去除水中大部分P,磷吸附剂则对PO43-有着极好的去除效果,处理出水可以实现PO43-几乎完全去除和TP达标;脱气塔的存在可以有效延长吸附剂的寿命;全套装置在运行过程中需要用到盐酸和烧碱,操作和管理难度较大,能耗及吸附剂再生成本较高;装置占地面积较大。因此该工艺的工程应用需综合考虑项目的实际情况来确定。     

农业废弃物作为吸附剂去除水中重金属研究

农业废弃物主要由纤维素和木质素组成,是一种潜在的重金属吸附剂。文中归纳了几种农业废弃物吸附剂及其改性方法,阐述了改性农业废弃物吸附重金属的机理,讨论了pH、重金属离子初始浓度、吸附剂用量、反应温度等因素对改性农业废弃物吸附能力的影响,并展望了改性农业废弃物的应用前景。     

Phosphorus recovery as struvite from eutropic waters by XDA-7 resin

Phosphorus releases into aquatic environment and its subsequent contribution to eutrophication have resulted in a widespread global pollution issue. However, phosphorus is a non-renewable source. The potential supplies of phosphorus are decreasing worldwide. Therefore, removal and recovery of phosphorus from the eutropic waters is important, emergent and necessary. In this research, experiments for recovering phosphate from eutropic waters by anion exchange combined with struvite precipitation were conducted. The results indicated that the prepared XDA-7 resin was an effective adsorbent for phosphate. The adsorption isotherm of XDA-7 resin was found to be a modified Freundlich type. The maximum phosphate adsorption (20.9 mg/g) occurred in the pH range of 6.0-8.0. Phosphate adsorbed on the XDA-7 resin was effectively desorbed with 8% NaCl solution, and the resin was able to be regenerated with 3% NaClO and 4% NaOH solutions. Phosphate desorbed from the resin was recovered as magnesium ammonium phosphate (struvite). The obtained struvite was analyzed by acid dissolution method, scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The struvite precipitate was found to be 75.8% in purity, a high-value fertilizer.     

An integrated wastewater reuse concept combining natural reclamation techniques, membrane filtration and metal oxide adsorption.

In a Sino-German research project, a sustainable water reclamation concept was developed for different applications of municipal water reuse at the Olympic Green 2008 in Beijing, China. Results from pilot-scale experiments in Beijing and Berlin show that selective nutrient removal by adsorption onto granular ferric hydroxide (GFH) after a membrane bioreactor (MBR) can maintain a total phosphorus concentration of <0.03 microg L(-1) P, thus preventing eutrophication of artificial lakes. Operation time of GFH adsorption columns can be extended by regeneration using sodium hydroxide solution. A subsequent ultrafiltration (UF) membrane after bank filtration creates an additional barrier for pathogens and allows for further urban reuse applications such as toilet flushing. Short term bank / bio-filtration prior to UF is shown to effectively remove biopolymers and reduce membrane fouling.     

污泥碱解发酵液用于生活污水脱氮 除磷的效果研究

为了减轻水体富营养化程度,提高污水的脱氮除磷效果,并解决污泥减量化和资源化问题,本研究将碱预处理的污泥进行厌氧发酵产酸,并将发酵液作为污水脱氮除磷的外加碳源。研究结果表明：投加污泥发酵液后,出水氨氮浓度为0.3~0.5 mg/L,总磷浓度为0.5 mg/L,与未投加污泥发酵液相比分别降低了1.7~2.3 mg/L和3~4 mg/L。     

Chemical phosphorus removal to extremely low levels: experience of two plants in the Washington, DC area.

Chemical phosphorus removal using metal (iron and aluminium) salts is frequently used to control effluent soluble phosphorus levels in wastewater treatment plants. In the Washington DC area effluent phosphorus requirements are extremely stringent to protect the Chesapeake Bay. Full-scale data from two plants in the area were analysed to establish phosphate behaviour in the presence of iron. Titration experiments and mathematical modelling were performed to determine the role of ferric phosphate and hydroxide precipitation and other mechanisms that may potentially be involved in phosphorus removal. Iron addition is described in the model using a chemical equilibrium approach extended with surface charges and adsorption. The model verifies key observations from full-scale data: (a) extremely low orthophosphate levels can be achieved over a wide range of pH values, (b) a mixture of ferric phosphate and ferric hydroxide precipitate is forming with the hydroxide acting as sorbent, (c) molar ratios of Fe/P (iron dosed to phosphate removed) vary widely (1.0-3.9) based on the technology used and residual phosphate levels. The model will be a useful tool for engineers to optimise preliminary, simultaneous and tertiary P removal, both for design and plant operation.