高级氧化技术去除水中碘代X射线造影剂研究进展

碘代X射线造影剂在医学上的大量使用导致其在水环境中普遍存在,对生态系统和人体健康构成巨大威胁.传统的污水处理技术对碘代X射线造影剂去除效果不佳,应用高级氧化技术去除水中碘代X射线造影剂成为研究热点.本文系统分析了水环境中碘代X射线造影剂的理化性质、来源、危害及污染现状.综述了声化学氧化、光催化、过硫酸盐活化、芬顿和电化...     

离子电极连续测定食醋中的碘氟

采用柠檬酸－KOH为离子强度调节剂,用碘电极、氟电极直接测定食醛中碘氟的量。方法简便、快速。本方法碘氯 的最低检出限分别为4.3ug/L和24ug/L.     

水溶液中二氧化氯及系列氧化物的测定

根据碘离子在不同pH值与ClO2、Cl2、ClO2-、ClO3-发生不同反应的原理,提出同时分析含氯系列氧化物的方法.相对标准偏差1.2%～6.5%,加标回收率可达92.6%～94.8%.该方法不仅可用于测定二氧化氯发生器产物各组分的浓度,还能用于测定给水和废水处理中的二氧化氯.     

乙基橙褪色光度法测定加碘盐中微量碘（Ⅴ）

提出了在盐酸介质中,在溴化钾催化作用下,碘酸根氧化乙基橙褪色吸光光度法测定碘的新方法。结果表明,最大吸收波长为５１０ｎｍ时,碘（Ⅴ）浓度在０～１．６ｍｇ／Ｌ内呈线性关系,表观摩尔吸光系数为４．４×１０４,方法用于加碘盐中碘（Ⅴ）的测定,结果满意。     

Quantification of pore clogging characteristics in potential permeable reactive barrier (PRB) substrates using image analysis

Permeable reactive barriers (PRBs) are now an established approach for groundwater remediation. However, one concern is the deterioration of barrier material performance due to pore clogging. This study sought to quantify the effect of pore clogging on the alteration of the physical porous architecture of two novel potential PRB materials (clinoptilolite and calcified seaweed) using image analysis of SEM-derived images. Results after a water treatment contaminated with heavy metals over periods of up to 10 months identified a decrease in porosity from c. 22% to c. 15% for calcified seaweed and from c. 22% to c. 18% for clinoptilolite. Porosity was reduced by as much as 37% in a calcified seaweed column that clogged. The mean pore size (2D) of both materials slightly decreased after water treatment with c. 11% reduction in calcified seaweed and c. 7% reduction in clinoptilolite. An increase in the proportion of crack-shaped pores was observed in both materials after the contaminated water treatment, most noticeably in the bottom of columns where contaminated water first reacted with the material. The distribution of pores (within a given image) derived from the distance transform indicated the largest morphological differences in materials was recorded in calcified seaweed columns, which is likely to impact significantly on their performance as barrier materials. The magnitude of porosity reduction over a short time period in relation to predicted barrier longevity suggest these and similar materials may be unsuited for barrier installation in their present form.     

海藻酸代谢菌的筛选及其性能研究

中国海岸线经常出现由海藻引起的海洋环境污染,海藻的有效利用有利于解决海洋环境问题。利用海藻发酵生产乙醇成为一项有前途的课题,但海藻中重要的多糖成分海藻酸却不能被利用。本课题以海藻酸钠为唯一碳源,初筛出了6株具有较强发酵能力的菌株,进一步摇瓶复筛,获得4株利用海藻酸生产乙醇能力较好的菌株,其中乙醇产率最高的为菌a。选取菌a进行菌株的形态观察及简单的生理生化特征分析,确定该菌株的类型。     

Impact of chlorine exposure time on disinfection byproduct formation in the presence of iopamidol and natural organic matter during chloramination

Chloramines,in practice,are formed onsite by adding ammonia to chlorinated drinking water to achieve the required disinfection.While regulated disinfection byproducts(DBPs)are reduced during chloramine disinfection,other DBPs such as iodinated(iodo-)DBPs,that elicit greater toxicity are formed.The objective of this study was to investigate the impact of prechlorination time on the formation of both halogen-specific total organic halogen(TOX)and iodo/chlorinated(chloro-)DBPs during prechlorination/chloramination in source waters(SWs)containing iopamidol,an X-ray contrast medium.Barberton SW(BSW)and Cleveland SW(CSW)containing iopamidol were prechlorinated for 5–60 min and afterwards chloraminated for 72 hr with ammonium chloride.Chlorine contact time(CCT)did not significantly impact total organic iodine(TOI)concentrations after prechlorination or chloramination.Concentrations of total organic chlorine(TOCl)formed during prechlorination did not significantly change regardless of pH and prechlorination time,whileTOClappearedtodecreaseafter 72 hrchloraminationperiod.Dichloroiodomethane(CHCl_2I)formation during prechlorination did not exhibit any significant trends as a function of p H or CCT,but after chloramination,significant increases were observed at pHs 6.5 and 7.5 with respect to CCT.Iodo-HAAs were not formed during prechlorination but were detected after chloramination.Significant quantities of chloroform(CHCl_3)and trichloroacetic acid(TCAA)were formed during prechlorination but formation ceased upon ammonia addition.Therefore,prechlorination studies should measure TOX and DBP concentrations prior to ammonia addition to obtain data regarding the initial conditions.     

Accelerating progress on salt iodisation in Sudan: time for action

This paper uses a public health approach to examine briefly: (a) the progress of universal salt iodisation (USI) in Sudan; (b) the roles of the main actors involved; and (c) the main issues around accelerating USI. The literature, especially that coming from the UN agencies, is analysed and experiences from the recently revitalised USI programme, and related relevant meetings, are distilled. In Sudan the prevalence of goitre is 22 per cent. It is assumed that productivity among the people affected is reduced by 5–25 per cent. Little apparent progress has been made with USI. The Government of Sudan, UN multilateral agencies, international consultative groups, bilateral agencies, global and national non-governmental organisations and, increasingly, the private sector must work together to find innovative approaches to increase awareness of the broader social, public health and nutritional contexts, and to advocate for increased national nd international funding.     

我国降水、降尘中硒、碘、氟的研究

研究了我国东甫沿海至西北地区降水、降尘中硒、碘、氟的分布及其影响因素,结果表明。我国降水硒、碘、氟含量范围分别为0.03—0.59ppb、0.3—3.8ppb和0.03—0.6ppm,一般为0.1—0.2ppb、1—2ppb和0.05—0.1ppm,其主要影响因素为人类活动,海洋、风沙及土壤微生物亦各有不同程度的影响。以集尘桶采集的降尘硒、碘、氟含量均远高于当地表层土壤,主要受当地大气污染状况、降尘量、降水量及降水中该元素含量的影响。硒、碘、氟三元素的挥发性与水迁移性的相互关系在很大程度上决定着我国四大地方病的分布。