饮用水除氟技术的研究现状及发展趋势

饮用高氟水危害人体健康是个世界性问题，已越来越受到人们的重视。基于近年来饮用水除氟技术的研究进展，就目前主要饮用水除氟技术如混凝沉淀，吸附过滤，电凝聚，电渗析和反渗透等及除氟技术中存在的问题进行了阐述，并提出了饮用水除氟技术向绿色技术发展的趋势。     

纳滤选择性除氟净水工艺介绍

高氟饮用水一直威胁着人类的健康,纳滤膜技术以其出水水质稳定、选择性分离和保留一定离子等优点,使其在饮用水处理中具有较好的应用前景。文章详细介绍了高氟饮用水特点、国内外相关除氟技术和纳滤选择性除氟技术的特点及其应用研究的最新进展,并给出纳滤除氟系统在应用设计中优化组合排布的建议。     

国内饮用水除氟方法的研究进展

我国是高氟地下水分布广泛的国家,研究去除饮用水中的氟离子非常重要。笔者通过介绍目前饮用水中主要除氟方法,针对目前除氟方法的研究进展,探究在实际除氟应用中的可行性,指出今后饮用水除氟研究方向并进行阐述。     

除氟剂性能的比较研究

静态试验及对除氟量的计算表明，活性氧化铝的除氟性能好，且粒径越小，吸附氟的能力越强；而活性炭对水中的氟无吸附能力。动态试验表明，活性氧化铝与树脂的除氟性能相差较大，树脂适用于对出水氟含量要求较严格的场合；对于生活饮用水的除氟处理宜采用活性氧化铝作除氟剂。采用活性氧化铝除氟成本较低，对北京市郊区的含氟地下水，建议采用活性氧化铝作除氟剂。     

高氟饮用水的脱氟研究进展

本文阐述了高含氟饮用水的处理方法,并对各种方法的优缺点,除氟机理进行了探讨。     

电渗析除氟的一般规律及计算

我国饮用水标准中,规定氟的含量为0.5～1.0毫克/升。如含氟量超过上限标准,会引起不同程度的地方性氟中毒。含氟量越高,氟中毒的病症越明显而病情越严重。 预防地方性氟中毒的根本措施是从饮用水中除去超量的氟。目前我国研究和使用的饮用水除氟方法有许多种。近年来已有不少单位使     

饮用水除氟的试验研究

本文对沸石、骨炭和活性氧化铝三种除氟剂的除氟性能、处理后的水质通过静态和动态试验进行了研究.结果表明沸石价格低廉,具有越用越好的趋势,处理后的水质和水量能满足家庭饮用水的需要,适用于高氟区家庭使用;骨炭和活性氧化铝除氟效果较好、技术成熟,适用于处理厂集中处理使用.     

AlF_n~（3－n）在饮用水中各形体的分布

根据有关公式算出不同的ｐＨ值、不同游离Ｆ~－浓度时ＡｌＦ各形体的分布系数（α_ｎ），并导出计算平均配位数公式，进而算出有关饮用水除氟方法的最佳ｐＨ值范围。     

合成骨炭除氟研究

合成骨炭除氟研究刘建荣武丽文李晋（太原工业大学）１概述氟是人体必需的微量元素之一，但摄取过量的氟会损伤人体健康。饮用水中含氟超过１ｍｇ／Ｌ称高氟水，它能使儿童患氟斑牙；长期生活在４ｍｇ／Ｌ以上高氟区者，会发生氟中毒，严重者可致残。据卫生部地病司调查，...     

应用于饮用水中除锰技术的研究进展

在我国饮用水资源中,含锰元素的水源所占比例较高,除锰技术的发展直接影响到饮用水的使用安全问题。介绍了除锰工艺、除锰技术滤料、除锰技术影响条件和生物法除锰细菌几个方面研究进展,举例说明除锰技术在饮用水处理中的应用实例,分析除锰技术在饮用水处理中的发展方向。     

Defluoridation from aqueous solutions by granular ferric hydroxide (GFH)

This research was undertaken to evaluate the feasibility of granular ferric hydroxide (GFH) for fluoride removal from aqueous solutions. Batch experiments were performed to study the influence of various experimental parameters such as contact time (1 min-24 h), initial fluoride concentration (1-100 mg L⁻¹), temperature (10 and 25 °C), pH (3-12) and the presence of competing anions on the adsorption of fluoride on GFH. Kinetic data revealed that the uptake rate of fluoride was rapid in the beginning and 95% adsorption was completed within 10 min and equilibrium was achieved within 60 min. The sorption process was well explained with pseudo-first-order and pore diffusion models. The maximum adsorption capacity of GFH for fluoride removal was 7.0 mg g⁻¹. The adsorption was found to be an endothermic process and data conform to Langmuir model. The optimum fluoride removal was observed between pH ranges of 4-8. The fluoride adsorption was decreased in the presence of phosphate followed by carbonate and sulphate. Results from this study demonstrated potential utility of GFH that could be developed into a viable technology for fluoride removal from drinking water.     

High yield combustion synthesis of nanomagnesia and its application for fluoride removal

We describe a novel combustion synthesis for the preparation of Nanomagnesia (NM) and its application in water purification. The synthesis is based on the self-propagated combustion of the magnesium nitrate trapped in cellulose fibers. Various characterization studies confirmed that NM formed is crystalline with high phase purity, and the particle size varied in the range of 3-7 nm. The fluoride scavenging potential of this material was tested as a function of pH, contact time and adsorbent dose. The result showed that fluoride adsorption by NM is highly favorable and the capacity does not vary in the pH range usually encountered in groundwater. The effects of various co-existing ions usually found in drinking water, on fluoride removal were also investigated. Phosphate was the greatest competitor for fluoride followed by bicarbonate. The presence of other ions studied did not affect the fluoride adsorption capacity of NM significantly. The adsorption kinetics followed pseudo-second-order equation and the equilibrium data are well predicted by Frendlich equation. Our experimental evidence shows that fluoride removal happened through isomorphic substitution of fluoride in brucite. A batch household defluoridation unit was developed using precipitation-sedimentation-filtration techniques, addressing the problems of high fluoride concentration as well as the problem of alkaline pH of the magnesia treated water. The method of synthesis reported here is advantageous from the perspectives of small size of the nanoparticle, cost-effective recovery of the material and improvement in the fluoride adsorption capacity.     

Manganese-oxide-coated alumina: a promising sorbent for defluoridation of water

In this study, adsorption potential of a new sorbent manganese-oxide-coated alumina (MOCA) was investigated for defluoridation of drinking water using batch and continuous mode experiments. The effects of different parameters such as pH, initial fluoride concentration and co-existing ions (usually present in groundwater sample) were studied to understand the adsorption behavior of the sorbent under various conditions. Optimum removal of fluoride ions occurred in a pH range of 4-7. Results of the present study indicate that fluoride adsorption rate and adsorption capacity of MOCA are far superior to that of activated alumina (AA), which was used as the base material for MOCA preparation. The MOCA can be effectively regenerated using 2.5% NaOH as eluent. The Langmuir equilibrium model was found to be suitable for describing the fluoride sorption on AA and MOCA. The maximum fluoride uptake capacity for MOCA and AA was found to be 2.85 and 1.08 mg g(-1), respectively. The kinetic results showed that the fluoride sorption to MOCA followed pseudo--second-order kinetics with a correlation coefficient greater than 0.98. The fluoride sorption capacity at breakthrough point for both the adsorbents was greatly influenced by bed depth. A bed depth service time (BDST) approach was adopted to describe the continuous flow system. The batch and column studies demonstrated the superiority of MOCA over AA in removing fluoride from the drinking water system.     

Assessment of water contribution on total fluoride intake of various age groups of people in fluoride endemic and non-endemic areas of Dindigul District, Tamil Nadu, South India

The prevalence of fluorosis is mainly due to the intake of large quantities of fluoride through water. It is necessary to determine the contribution of water used for drinking and food processing and other diet sources on daily fluoride intake for finding the ways to reduce the excess fluoride intake than the minimum safe level intake of 0.05 mg/kg/day. The main objectives of this study are to determine the quantitative impact of water through drinking and cooking of food and beverages on total fluoride intake as well as to estimate the contribution of commonly consumed diet sources on total fluoride intake. Contribution of water on daily fluoride intake and estimation of total fluoride intake through the diet sources were accomplished through analysis of fluoride in drinking water, solid and liquid food items, Infant formulae, tea and coffee infusions using fluoride ion selective electrode. Determination of incidence of fluorosis in different fluoride endemic areas in Dindigul District of Tamil Nadu, South India is achieved through clinical survey. The percentage of daily fluoride intake through water is significantly higher for infants than children, adults and old age groups of people. The percentile scores of fluoride intake through water from drinking and cooking increases with increase of water fluoride level. The rate of prevalence of fluorosis is higher in adolescent girls and females than adolescent boys and males residing in high fluoride endemic areas. More than 60% of the total fluoride intake per day derived from water used for drinking and food processing. Hence the people residing in the fluoride endemic areas in Dindigul District of Tamil Nadu, South India are advised to take serious concern about the fluoride level of water used for drinking and cooking to avoid further fluorosis risks.     

锌铝电极电絮凝法处理高氟饮用水的研究

在双铝极板电絮凝法的基础上引入锌电极,考察锌铝电极电絮凝法对高氟饮用水的除氟效果.静态试验结果表明,采用锌铝电极可以有效降低水中的氟离子浓度,对CODMn和浊度的去除效果优于双铝电极;当原水的氟离子浓度为6 mg/L时,最佳处理条件:锌、铝极板比为1:3、电解电压为18 V、反应pH值为6、反应时间为25～30 min.动态试验结果表明,当进水流量和氟离子浓度分别高达42 mL/min、8 ms/L时,调节进水pH值为6可使其出水中的氟离子浓度达标.     

Determining the optimal fluoride concentration in drinking water for fluoride endemic regions in South India

Fluoride ion in drinking water is known for both beneficial and detrimental effects on health. The prevalence of fluorosis is mainly due to the intake of large quantities of fluoride through drinking water owing to more than 90% bioavailability. The objective of this study is to predict optimal fluoride level in drinking water for fluoride endemic regions by comprising the levels of fluoride and other water quality parameters in drinking water, prevalence of fluorosis, fluoride intake through water, food and beverages such as tea and coffee and also considering the progressive accumulation of fluoride in animal bones, by comparing with non fluoride endemic areas comprise of the same geological features with the aid of regression analysis. Result of this study shows that increase of fluoride level above 1.33 mg/l in drinking water increases the community fluorosis index (CFI) value more than 0.6, an optimum index value above which fluorosis is considered to be a public health problem. Regression plot between water fluoride and bone fluoride levels indicates that, every increase of 0.5 mg/l unit of water fluoride level increases the bone fluoride level of 52 mg/kg unit within 2 to 3 years. Furthermore, the consumption of drinking water containing more than 0.65 mg/l of fluoride can raise the total fluoride intake per day more than 4 mg, which is the optimum fluoride dose level recommended for adults by the Agency for Toxic Substances and Disease Registry. From the result, the people in fluoride endemic areas in South India are advised to consume drinking water with fluoride level within the limit of 0.5 to 0.65 mg/l to avoid further fluorosis risk.     

Mapping of fluoride endemic areas and assessment of fluoride exposure

The prevalence of fluorosis is mainly due to the consumption of more fluoride through drinking water. It is necessary to find out the fluoride endemic areas to adopt remedial measures to the people on the risk of fluorosis. The objectives of this study are to estimate the fluoride exposure through drinking water from people of different age group and to elucidate the fluoride endemic areas through mapping. Assessment of fluoride exposure was achieved through the estimation fluoride level in drinking water using fluoride ion selective electrode method. Google earth and isopleth technique were used for mapping of fluoride endemic areas. From the study it was observed that Nilakottai block of Dindigul district in Tamil Nadu is highly fluoride endemic. About 88% of the villages in this block have fluoride level more than the prescribed permissible limit in drinking water. Exposure of fluoride among different age groups was calculated in this block, which comprises 32 villages. The maximum estimated exposure doses were 0.19 mg/kg/day for infants, 0.17 mg/kg/day for children and 0.10 mg/kg/day for adults. When compared with adequate intake of minimal safe level exposure dose of 0.01 mg/kg/day for infants and 0.05 mg/kg/day for other age groups, a health risk due to fluorosis to the people in Nilakottai block has become evident. From the results, the people in Nilakottai block are advised to consume drinking water with fluoride level less than 1 mg/l. It has been recommended to the government authorities to take serious steps to supply drinking water with low fluoride concern for the fluorosis affected villages.     

两种不同材质超滤膜处理饮用水的综合性能研究

研究了两种不同材质超滤膜处理饮用水的综合性能。结果表明,聚醚砜(PES)膜对CODMn及TOC的去除效果优于聚偏氟乙烯(PVDF)膜;PES与PVDF膜对浊度的去除效果相差不大,大部分出水浊度小于0.10 NTU;PES和PVDF膜对UV254无去除效果;PVDF膜比PES膜的跨膜压差高15%左右,且抗污性能比PES膜强,其电耗水平比PES膜高50%左右。     

Contribution of trona (magadi) into excessive fluorosis--a case study in Maji ya Chai ward, northern Tanzania

Excessive fluoride ingestion predominantly comes from drinking water sources. However, prevalence and severity of dental and skeletal fluorosis in northern Tanzania have been reported to be higher than would be expected from ingestion of fluoride through drinking water alone. This study aimed at investigating the contribution of "trona" (also locally known as magadi) a food additive, to the prevalence and severity of fluorosis in northern Tanzania. The study was carried out in four villages (Embaseni, Kitefu and Ngurdoto) in Maji ya Chai ward; and Nkoanekoli in Poli ward, in Arusha region, Tanzania. Analysis of fluoride concentrations was carried out in drinking water sources as well as in magadi samples. Assessment of the prevalence of dental fluorosis using Dean's Index Method was carried out for a population of 2217 pupils in four primary schools located in the case study area. Fluoride concentration in drinking water sources was found to range from 1.7 to 11.3 mg/l, while the concentration in magadi samples in case study villages were in the range of 0.21 to 0.9 mg/g. Total fluoride ingestion through magadi and water were established to be 11.74 mg/person/day in Embaseni, 36.1 mg/person/day in Ngurdoto, 10.88 mg/person/day in Kitefu and 5.7 mg/person/day in Nkoanekoli villages. Levels of total fluoride ingestion were directly correlated with Community Fluorosis Index (CFI) values, which were found to be 3.32 (in Embaseni), 3.67 (in Ngurdoto), 2.2 (in Kitefu) and 1.47 (in Nkoanekoli). The village with the highest fluoride consumption rate showed the highest CFI as well. High levels of fluoride concentrations in magadi suggest that excessive fluorosis in northern Tanzania may be due to the use of magadi in food preparations.     

复合电极电吸附去除水中氟离子的研究

采用复合电极对用蒸馏水加氟化钠配制成的含氟水溶液进行了动态电吸附除氟实验,研究了不同电压、流量、初始浓度对氟离子去除的影响。实验结果表明:以复合电极为电极材料,采用电吸附方法可以有效地去除水中的氟离子,复合电极对氟离子的去除与所施加的电压、流量以及初始浓度都有一定的关系。增大电压,减小进水流量,降低氟离子的初始浓度,都可提高氟的去除率。