Effect of chemical modification of wool on metal ion binding

The effect of specific functional group modification of wool on the binding of a number of metal ions (individually) from aqueous solutions was studied. The metal ion uptake profiles for the different modified keratin polymers show that a degree of specificity of binding is imparted by the various modifications in terms of changes in capacities or rates of metal ion uptakes. The changes of uptake depend on both the particular ion and the particular protein modification involved. The results show the potential usefulness of the keratin derivatives for removal of toxic and industrial metal ions from water and contribute to interpretation of metal ions interactions with native wool and proteins in general. Treatments of woven wool with aqueous solutions of certain metal salts impart flame and insect resistance to the fabric.     

Sorption behavior of mercuric and methylmercuric salts on wool

Sorption by wool of mercuric nitrate, mercuric chloride, and methylmercuric chloride was measured by atomic absorption spectroscopy. Both inorganic mercury compounds are efficiently taken up at low concentrations from acid solution. The rate of binding from the nitrate is appreciably slower than from the chloride. Methylmercuric chloride is bound slowly at low pH, rapidly at pH 6. The extent of its binding is roughly 10% to 20% of that of the inorganic salts. The wool-bound mercury can be recovered by serial extraction with aqueous citrate or ethylenediaminetetraacetate at pH 6. The residual, firmly bound mercury is roughly equivalent to the sulfhydryl sulfur. Sorption of inorganic mercury compounds at low pH roughly follows a Freundlich isotherm in the concentration range 5×10^-6 to 10^?1M. Sorption of methylmercurie chloride at pH 6 follows a roughly parallel isotherm in the range 5×10^?6 to 10^?3M. These data suggest the potential value of wool and other animal keratins to remove and recover mercury from contaminated water. Wool may also serve as an instructive model for mercury binding and release in the body.     

Removal and recovery of mercury from chloride solutions by contact deposition on iron felt

This paper deals with the use of iron felt as a reducing agent for the removal of mercury from aqueous dilute solutions containing chloride ions. The kinetic behavior of the mercuric ion reduction was analyzed and its diffusion coefficient was determined with the use of a rotating disk electrode. Experimental results of the removal of mercury from aqueous sodium chloride solutions containing 100 ppm mercury by contact with iron felt are reported. The mercury concentration was decreased to values lower than 0·1 ppm. The recovery of metallic mercury by chemical attack of the residual iron felt was also analyzed.     

Extraction and Precipitation Chemistry for Mercury Recovery from Aqueous Wastes

Abstract

This paper describes an extraction-precipitation process to recover mercuric chloride from aqueous solutions. The process is a modification of a dicarboxylic acid recovery process that exploits the enhanced solubility of mercuric chloride in organic solvents loaded with water. Mercuric chloride in ethyl acetate has a solubility enhancement of 1.34 moles mercuric chloride per mole of water added to the solvent, consistent with previously reported phase behavior. Solubility enhancement is also reported for formates, in contrast to previously reported results. For example, propyl formate showed 2.91 moles mercuric chloride per mole water enhancement.

The modified process described in this paper relies on (1) favorable liquid-liquid equilibrium (mercuric chloride distribution into ethyl acetate or into propyl formate), (2) favorable liquid-solid equilibrium with enhanced solute solubility on addition of a minor constituent (water), and (3) preferential vaporization of the minor constituent from the solid slurry (relative volatility of water in mercuric chloride loaded ethyl acetate is four). Enhanced solubilities for zinc(II) chloride(3.46) and mercury(II) iodide(1.10) in isopentyl acetate indicate a potential application of the process for the recovery of other metal halides from aqueous wastes.     

Binding of metal cations by natural substances

The binding of mercuric chloride and other metal salts to bark, activated sludge (Milorganite), chitosan, poly(p-aminostyrene), and other natural and synthetic materials was investigated by specific atomic absorption and x-ray fluorescence spectroscopy. The synthetic poly(aminostyrene) was included for comparison with the natural polyamine chitosan. Our results show that a wide range of natural materials are potentially useful for the removal of toxic and precious metals that may be present in industrial effluents, mine waters, or other water supply. Such metal salts include those of mercury, lead, zinc, cadmium, copper, nickel, cobalt, iron, manganese, silver, platinum, palladium, and gold.     

Mercury removal and recovery by immobilized Bacillus megaterium MB1

From several mercury removing microorganisms, we selected Bacillus megaterium MB1, which is non-pathogenic, broad-spectrum mercury resistant, mercuric ion reducing, heat tolerant, and spore-forming, as a useful bacterium for bioremediation of mercury pollution. In this study, mercury removal performance of the immobilized B. megaterium MB1 was investigated to develop safe, efficient and stable catalytic bio-agent for mercury bioremediation. The results showed that the alginate gel immobilized B. megaterium MB1 cells efficiently removed 80% of mercury from the solution containing 10 mg/L mercuric chloride within 24 h. These cells still had high activity of mercury removal even after mercuric ion loading was repeated for nine times. The analysis of mercury contents of the alginate beads with and without immobilized B. megaterium MB1 suggested that a large portion of reduced metallic mercury was trapped in the gel beads. It was concluded that the alginate gel immobilized B. megaterium MB1 cells have potential to remove and recover mercury from mercury-containing water.     

氯碱工业汞污染问题分析

由于汞的使用和管理不善,采用水银电解法生产烧碱过程中,大量的汞随废水和盐泥排到外环境中;采用乙炔法生产醋酸或氯乙烯时,因使用含汞催化剂,生产中也会有少量汞随废水排入到外环境,造成严重的汞污染.我国虽然于"十五"初期已彻底淘汰水银法烧碱,"十五"后期淘汰了汞法醋酸,但这两类装置遗留的汞污染问题依然十分严重,乙炔法氯乙烯生产排放的含汞废水问题也不应忽视,各级政府和管理部门对此要高度重视,争取早日解决现存的汞污染问题.     

氯化汞触媒在使用过程中的回收利用

介绍了氯化汞触媒回收利用现状,我国每年实际产汞量约1 100 t,用汞总量为1 100~1 500 t,在PVC行业中每年用汞总量为700~900 t、流失量却在560 t以上;分析了氯化汞触媒流失的方向;提出了回收氯化汞触媒的可行性方法及建议。     

Removal of mercuric ions by systems based on cellulose derivatives

A few cellulose derivatives were prepared by the reaction of chlorodeoxycellulose (CDC) with ethylenediamine (ED), thiourea, thiosemicarbazide, thioacetamide, and others. These derivatives were found to be able to remove mercuric ions to an extent greater than 99% from a 10 ppm aqueous solution of mercuric chloride. For example, thiocellulose obtained by reacting CDC with thiourea and subsequently hydrolyzing it showed such good removal in the batch and continuous removal tests which involved passing the solution through a column packed with this cellulose derivatives.     

加强汞污染防治 实现聚氯乙烯清洁生产

介绍了电石乙炔法生产氯乙烯工艺中氯化汞催化剂汞的流向、汞的流失查定及汞的削减措施等。     

Adsorption of Heavy Metal Salts by Cotton Fabrics Containing Polyethylene and Polypropylene Sulfide

The adsorption of mercury and other heavy metal salts by cotton fabrics containing polyethylene and polypropylene sulfide was investigated. Adsorption of mercuric chloride from aqueous solution was investigated in detail, and AH of the reaction was determined. A general screening of the capacity of adsorption of the polymers for heavy metal salts was carried out. Differences in behavior between the polymeric system and simple thioethers were observed. Auric, antimony, titanium, palladium, platinum and bismuth salts were adsorbed by the modified cotton; other salts, known also to complex with organic sulfides, were not adsorbed.     

乙炔法合成氯乙烯用氯化汞催化剂的改良

简单介绍了乙炔法合成氯乙烯的反应原理、工艺流程、操作条件和主要技术指标,以及氯化汞催化剂的规格和制备方法,讨论了氯化汞催化剂的缺陷,总结了在减少汞流失方面对氯化汞催化剂进行改良的进展情况。     

硝酸汞滴定法测定磷矿石中氯离子含量

根据磷矿石原料的特殊性,建立了测定其中氯离子含量的方法.磷矿石用稀硝酸溶解,提取出的氯离子在pH2.5 ～ pH3.5的乙醇环境中,与硝酸汞反应生成难电离的氯化汞,过量的汞离子与二苯偶氮碳酰肼生成蓝紫色的汞配合物以指示终点.加标回收率在97.1％～101.4％,相对标准偏差为1.5％～1.8％.     

加快开发高效复方氯化汞触媒

简述了氯化汞触媒在乙炔合成氯乙烯工艺过程中的使用缺陷。基于汞资源的匮乏以及氯化汞触媒对环境污染的现实,提出了研究新型复方氯化汞触媒的重要性。     

Heavy metal ion adsorbents having thioamide groups

Polyhydrazides are prepared by condensation of cyanuric chloride with dihydrazides of dibasic carboxylic acids and are sulfurized with phosphorus pentasulfide. Copolymers of acrylamide and dimethylacrylamide with divinylbenzene are also sulfurized with phosphorus pentasulfide. The sulfurized polymers adsorb mercuric ion. In order to incorporate thiocarbamide groups into a polymer matrix, methylolthioureas are condensed with polyethylenimine. The reactions are carried out in the solid state or in aqueous solution. In the former, water is distilled off from the solidified mixture of the reactants; in the latter, methylothiourea and polyethylenimine are allowed to react in the presence of sulfuric acid. The products are good mercuric ion adsorbents.     

我国氯化汞触媒生产和废氯化汞触媒回收利用技术进展

综述了我国氯化汞触媒生产技术进展和废汞触媒回收利用技术进展,阐述了非氯化汞触媒的研制情况,并对氯化汞触媒行业提出了创建涉汞循环经济的建议.     

优化工艺 提高汞的使用效率

在电石法氯乙烯合成过程中,通过对反应温度、原料气纯度、混合脱水自动控制水平和脱水效果以及对气相和液相的汞进行回收等工艺的控制,有效地提高了氯化汞催化剂的使用效率,降低了汞的使用量,减少了流失汞对环境造成的污染。     

硝酸中微量氯离子测定方法探讨

进行了莫尔法、佛尔哈德法、硫氰酸汞分光光度法测定实际硝酸样品和标样中微量Cl^-含量的对比试验,结果表明：莫尔法不能准确测定硝酸中微量Cl^-含量,硫氰酸汞分光光度法和佛尔哈德法能准确测定硝酸中微量Cl^-含量。通过试验,还确定了硫氰酸汞分光光度法和佛尔哈德法测定硝酸中微量Cl^-含量的条件。     

氯化汞催化剂汞污染防治措施

介绍了电石法聚氯乙烯生产工艺中氯化汞催化剂汞污染防治措施,包括低汞催化剂应用,汞流向查定,气相汞、液相汞和盐酸中汞的治理等方面。     

Isolation of pure linolenate as its mercuric acetate adduct

After addition of mercuric acetate to the unsaturated methyl esters obtained from the methanolysis of linseed oil, linolenate of 99% minimum purity was isolated by means of a liquid-liquid continuous extraction technique and subsequent decomposition of the mercurial adduet. The methyl linolenate-mercuric acetate addition compound was extracted with 10% methanol in water from an ether solution of the reaction mixture. Infrared analysis of the regenerated methyl linolenate showed the complete absence oftrans-linkages. The yield, at least 60% of the linolenic acid present in linseed oil, was considerably higher than that obtained by bromination-debromination procedures. The solubility in aqueous solutions of fatty acid derivatives having 3 or more acetoxymer-euri-groups/molecule provides an approach to the fractionation of highly unsaturated oils. For example, a fraction having an iodine value of 395 was isolated readily from the methyl esters of pilchard oil by this technique. Journal Paper No. 1787, Purdue Agricultural Experiment Station.