基于数字图像比色法测定水中氟化物

在酸性溶液中,氟能破坏二甲酚橙〖CD*2〗锆显色体系,使溶液颜色从紫红色变为橙色或黄色,通过采集图像颜色信息构建3个特征颜色分量的多元线性回归模型,用以定量测定水中氟。该方法在0 mg/L~1.5 mg/L范围内线性良好,方法检出限为0.03 mg/L。两个质量浓度水平的氟化物标准溶液6次测定结果的RSD分别为1.4%和1.3%,相对误差分别为0.3%和1.7%。     

瑞平塘河氟化物污染状况调查及溯源研究

以2016—2020年地表水常规监测结果为依据,发现瑞平塘河自2017年起出现氟化物质量浓度升高现象,2020年其中1个断面氟化物质量浓度平均值达到1.25 mg/L,比2016年高出145%。为此于2021年3—6月,对瑞平塘河流域的氟化物污染状况进行实地调查并开展溯源研究。研究结果显示,2021年氟化物质量浓度超过1.0 mg/L的点位占59.34%,其中超过1.5 mg/L的点位占42.86%,表明大部分河道氟化物质量浓度已经超过水体功能区要求,对生态环境安全构成较大潜在风险。溯源调查结果表明,排除了农业源及矿山源污染的可能,乳胶制品企业排放的废水为瑞平塘河氟化物的污染来源。针对目前该行业的排放标准和环境影响评价均未提及氟化物污染,企业废水处理设施也无除氟工艺单元,缺乏有效的污染防治措施与监管要求等问题。提出,应及时组织开展该区域乳胶制品行业整治提升,增加氟化物处理工艺单元,提升出水水质,确定氟化物排放浓度限值,并对该行业排放标准做进一步研究和完善等建议。     

硫铁矿生产硫酸的废水治理

电石渣中和－精密微孔过滤技术治理硫酸废水的工艺简洁、可靠，占地面积小，运行费用低，出水优于国家二级排放标准。     

Temporal variation of fluoride concentration in antlers of roe deer (Capreolus capreolus) living in an area exposed to emissions from iron and steel industry, 1948-2000

Temporal changes of environmental fluoride concentration in the industrialized area of Siegen, western Germany were assessed by studying the fluoride content of antlers (n=116) collected between 1948 and 2000 from the resident roe deer (Capreolus capreolus) population. During the analyzed period, major fluoride emission sources in the study area have been iron- and steelworks. Fluoride concentrations in the antlers ranged between 118 and 5428 mg/kg of bone ash. There was an overall increase in antler fluoride content from the late 1940s/early 1950s to the late 1950s/mid-1960s. Thereafter, antler fluoride levels overall steadily declined. For statistical analysis, the data were grouped into five periods (1948–1959, 1960–1969, 1970–1979, 1980–1989, and 1990–2000). Geometric mean fluoride concentrations of the samples ranged from 323 (period 1990–2000) to 2096 mg/kg of bone ash (period 1960–1969). Sample means for the periods 1980–1989 and 1990–2000, respectively, were always significantly lower than those of older samples. The decrease in antler fluoride concentrations during recent decades suggests a drop of ambient fluoride levels, that is hypothetically attributed to a reduction in the number of emission sources in the area and a decline of fluoride discharges from both local and more distant sources due to improved emission control measures. Comparison with antler fluoride data for other roe deer populations from western Germany further suggests that the roe deer from the Siegen area were recently exposed to an only moderate additional fluoride load from industrial sources. Studying antler fluoride concentrations is a convenient and cost-effective method of monitoring temporal changes in ambient fluoride levels.     

春蚕期桑叶氟化物含量变化规律分析与研究

春蚕桑叶氟化物中毒引起政府部门的高度重视。通过对历年来桑叶含氟量监测数据统计分析，找出春蚕期桑叶含氟量日均值变化规律，并对规律成因进行探讨研究，为春蚕防氟工作提供科学依据。     

Effects of fluoride on the removal of cadmium and phosphate by aluminum coagulation

This study focuses on the effects of pH and fluoride at different molar ratios of fluoride to Al (R_F:Al) on the removal of cadmium (Cd²⁺) and phosphate by Al coagulation. Fluoride at R_F:Al ≥ 3:1 inhibits the removal of Cd over wide Al dose ranges from 5 to 10 mg/L as Al. The removal of phosphate decreases significantly at high R_F:Al of 10:1 whereas at lowered R_F:Al (i.e., ≤ 6:1), an adverse effect is observed only at insufficient Al doses below 2 mg/L. Fluoride shows inhibitive effects towards the removal of Cd at pH 7 and 8 and that of phosphate at pH 6. Fluoride decreases the ζ-potential in both systems, and the decreasing extent is positively correlated to the elevated R_F:Al. The Al fluoride interactions include the formation of Al–F complexes and the adsorption of fluoride onto Al(OH)₃ precipitates, i.e., the formation of Al(OH)_nF_m. Al–F complex formation inhibits Al hydrolysis and increases residual Al levels, and a more significant increase was observed at lower pH. Al–F complexes at high R_F:Al complicate the coagulation behavior of Al towards both negative and positive ionic species. Moreover, fluoride at low R_F:Al shows little effect on Al coagulation behavior towards Cd^2 + and phosphate, and the spent defluoridation adsorbent, i.e., aluminum (Al) hydro(oxide) with adsorbed fluoride at R_F:Al of below 0.1:1, may be reclaimed as a coagulant after being dissolved.     

Fluoride removal performance of a novel Fe-Al-Ce trimetal oxide adsorbent

A trimetal oxide was developed as a fluoride adsorbent by coprecipitation of Fe(II), Al(III) and Ce(IV) salt solutions with a molar ratio of 1:4:1 under alkaline condition. The material retained amorphous structure and maintained relatively stable fluoride adsorption performance at calcination temperatures lower than 600 degrees C. The optimum pH range for fluoride adsorption was 6.0-6.5 and the adsorbent also showed high defluoridation ability around pH 5.5-7.0, which is preferable for actual application. A high fluoride adsorption capacity of 178 mg g(-1) was acquired under an equilibrium fluoride concentration of 84.5 mg l(-1), adsorbent dose of 150 mg l(-1) and pH 7.0. The adsorption isotherm could be better described by the two-site Langmuir model than the one-site model, suggesting the existence of two types of active sites on the adsorbent surface. Coexistence of high concentrations of phosphate or arsenate only led to partial inhibition of fluoride adsorption, which further suggests the existence of heterogeneous adsorption sites. Sulfate and chloride did not affect fluoride adsorption, and nitrate influenced it only when the concentration of NO(3)(-)-N exceeded 50 mg l(-1). A high desorption efficiency of 97% was achieved by treating fluoride loaded Fe-Al-Ce oxide with NaOH solution at pH 12.2. A column experiment using the adsorbent fabricated into 1mm pellets was performed at an initial fluoride concentration of 5.5 mg l(-1), space velocity of 5h(-1) and pH of 5.8, and 2240 bed volumes were treated with the effluent fluoride under 1.0 mg l(-1).     

粘土制砖过程中固氟剂的研究

基于制砖时氟易与钙结合生成高温下较稳定的ＣａＦ２,从而降低氯化物逸出量,在试验分析２４种钙基物料固氟效果的基础上,选取效果较佳的６种分别在实验室和砖瓦厂进行优化添加比例试验,对其中途中 作了砖质检验,以研究其可能对成品砖质量的影响,并进行了相应的理论分析。     

A health risk assessment for fluoride in Central Europe

Like many elements, fluorine (which generally occurs in nature as fluoride) is beneficial to human health in trace amounts, but can be toxic in excess. The links between low intakes of fluoride and dental protection are well known; however, fluoride is a powerful calcium-seeking element and can interfere with the calcified structure of bones and teeth in the human body at higher concentrations causing dental or skeletal fluorosis. One of the main exposure routes is via drinking water and the World Health Organisation currently sets water quality guidelines for the element. In Central Europe, groundwater resources that exceed the guideline value of 1.5 mg l⁻¹ are widespread and effects on health of high fluoride in water have been reported. The aim of the current project was to develop a geographic information system (GIS) to aid the identification of areas where high-fluoride waters and fluorosis may be a problem; hence, where water treatment technologies should be targeted. The development of the GIS was based upon the collation and digitisation of existing information relevant to fluoride risk in Ukraine, Moldova, Hungary and Slovakia assembled for the first time in a readily accessible form. In addition, geochemistry and health studies to examine in more detail the relationships between high-fluoride drinking waters and health effects in the population were carried out in Moldova and Ukraine demonstrating dental fluorosis prevalence rates of 60–90% in adolescents consuming water containing 2–7 mg l⁻¹ fluoride.     

Dental fluorosis associated with drinking water from hot springs in Choma district in southern province,Zambia

This study was conducted to investigate the high incidence of mottled teeth among residents of an area with hot springs in the Choma District of the Southern Province of Zambia. A survey involving 128 pupils was conducted at a Basic School to collect data on pupil’s backgrounds and their main sources of drinking water between birth and age 7. A dental specialist examined the pupils’ teeth and samples of drinking water were collected from locations where the majority of the pupils lived. It was analysed for fluorides and other drinking water quality parameters. Results of the survey showed a highly significant (P < 0.001) association between pupils’ main sources of drinking water between birth and age 7 and the incidence of discoloured teeth. All (100%) pupils who drank water from hot springs before age 7 had moderate to severe fluorosis, while the majority (96.7%) of the pupils who drank water from other sources had no dental fluorosis. Fluoride concentrations ranged from 5.95 to 10.09 mg/l in water from hot springs, and from 0.03 to 0.6 mg/l in water from other sources. Fluoride levels in water from hot spring water samples exceeded the 1.5 mg/l WHO guideline value for drinking water, while those in water from other sources were significantly (P < 0.05) lower than this. We conclude that the high prevalence of mottled teeth among residents of the study area is a case of endemic dental fluorosis associated with drinking water from hot springs containing high concentrations of fluoride.