Effective removal of heavy metals from aqueous solutions by orange peel xanthate

Preparation of orange peel xanthate and its adsorption behaviors of five heavy metals(Cu 2+ ,Cd 2+ ,Pb 2+ ,Zn 2+ and Ni 2+ ) were studied.FTIR spectra,Zeta potentials and TG analysis were used to characterize prepared orange peel xanthate.Effects of various parameters including equilibrium pH,initial metal ion concentration and adsorption time on the adsorption processes for the five metal ions were investigated.It was found that for all five metal ions,the adsorption isotherms agreed Langmuir model very well and the maximum adsorption capacities of Cu2 +,Cd 2+,Pb 2+,Zn 2+and Ni 2+were obtained as 77.60,76.57,218.34,49.85 and 15.45 mg/g,respectively.All adsorption processes can attain equilibrium within 20 min and kinetics was well fitted by psesudo-second order equation.It is proposed that the adsorption mechanism was complexation.

Improved hemimorphite flotation using xanthate as a collector with S(Ⅱ) and Pb(Ⅱ) activation

The flotation of hemimorphite using the S(Ⅱ)–Pb(Ⅱ)–xanthate process,which includes sulfidization with sodium sulfide,activation by lead cations,and subsequent flotation with xanthate,was investigated.The flotation results indicated that hemimorphite floats when the S(Ⅱ)–Pb(Ⅱ)–xanthate process is used; a maximum recovery of approximately 90% was obtained.Zeta-potential,contact-angle,scanning electron microscopy–energy-dispersive spectrometry(SEM–EDS),and diffuse-reflectance infrared Fourier transform spectroscopy(DRIFTS) measurements were used to characterize the activation products on the hemimorphite surface and their subsequent interaction with sodium butyl xanthate(SBX).The results showed that a Zn S coating formed on the hemimorphite surface after the sample was conditioned in an Na2 S solution.However,the formation of a Zn S coating on the hemimorphite surface did not improve hemimorphite flotation.With the subsequent addition of lead cations,Pb S species formed on the mineral surface.The formation of the Pb S species on the surface of hemimorphite significantly increased the adsorption capacity of SBX,forming lead xanthate(referred to as chemical adsorption) and leading to a substantial improvement in hemimorphite flotation.Our results indicate that the addition of lead cations is a critical step in the successful flotation of hemimorphite using the sulfidization–lead ion activation–xanthate process.

Degradation of n-butyl xanthate using fly ash as heterogeneous Fenton-like catalyst

Heterogeneous Fenton-like process using fly ash as a catalyst was studied to degrade n-butyl xanthate form aqueous solution. The different reaction parameters on the degradation efficiency of the process were investigated. The fly ash/H2O2 catalyst possesses a high oxidation activity for n-butyl xanthate degradation in aqueous solution. It is found that both the dosage of catalyst and initial solution pH significantly affect the n-butyl xanthate conversion efficient. The results indicate that by using 1.176 mmol/L H2O2 and 1.0 g/L fly ash catalyst with mass fraction of 4.14% Fe(III) oxide at pH 3.0, almost 96.90% n-butyl xanthate conversion and over 96.66% COD removal can be achieved within 120 min with heterogeneous catalysis by fly ash. CS2 as an intermediate of n-butyl xanthate oxidation. Finally, it is demonstrated that the fly ash/H2O2 catalytic oxidation process can be an efficient method for the treatment of n-butyl xanthate containing wastewater.

SYNERGISM OF WOLFRAMITE FLOTATION WITH BENZYL ARSONIC ACID AND SODIUM BUTYL XANTHATE

Wolframite notation with benzyl arsonic acid and sodium butyl xanthate is studied,at first.It shows the efficiency of mineral processig is good when the two agents are added together.Then the synergism of sodium butyl xanthate and benzyl arsonic acid is studied also by HPLC.

Synthesis of glycerine-xanthate and its depressing mechanism in separation of marmatite from arsenopyrite

A small molecular organic depressor glycerine-xanthate was synthesized. The effect of glycerine-xanthate on the flotation of sulfide minerals was investigated based on a function of pH value and concentration of glycerine-xanthate through flotation experiments in the presence and absence of Cu2+. The results show that glycerinee-xanthate has a strong dressing effect on marmatite at pH>6 and on arsenopyrite in weak acid and base conditions with butyl-xanthate as collector. In the presence of glycerine -xanthate, marmatite is activated by addition of Cu2+, but arsenopyrite cannot be activated and remains unfloatable. So the selective separation can be achieved for two minerals. The depression of glycerine-xanthate on sulfide minerals was discussed based on the radical electronegative calculation and the theory of HSAB. Infrared spectrum shows that there are some —OH and —CSS— in glycerine-xanthate molecule, which competes with butyl-xanthate on the mineral surface. As a result of many hydrophilic groups in glycerine-xanthate, the surfaces of marmatite and arsenopyrite become hydrophilic, thus the flotation of marmatite and arsenopyrite is depressed. The collector is adsorbed preferentially on the surface of marmatite and it shows a better floatability in the presence of Cu2+, whereas, the surface of arsenopyrite absorbs glycerine-xanthate and the flotation of arsenopyrite is depressed by glycerine-xanthate.

Cation exchange for mercury and cadmium of xanthated,sulfonated,activated and non-treated subbituminous coal,commercial activated carbon and commercial synthetic resin:effect of pre-oxidation on xanthation of subbituminous coal

A subbituminous coal was oxidized with air at 150℃on a fixed bed for 4 h and xanthated with carbondisulfide in a basic solution,at 30 or 5-10℃.This xanthated coal was evaluated for the removal of Hg^(2+)and Cd^(2+)from 7,000 mg/L aqueous solutions;metal concentrations were detemmined by atomic absorption spectrometry.The ionexchange of the xanthated coal was compared against those of the original subbituminous coal,a sulfonated subbituminouscoal,activated carbon,commercial activated carbon,and commercial synthetic resin.The commercial synthetic resinshowed the highest exchange capacity(concentration factor 98%)followed by the xanthated coal(concentration factor 96%).The retention of cadmium on the sulfonated subbituminous coal was lower(exchange capacity 0.56 meq/g)thanthat of xanthated coals(1.85±0.09 meq/g).Our xanthated coal showed a better Cd^(2+)removal(8l%o against 15%)than anon preoxidized 40-h-xanthated coal,which shows that oxidation of coal increased the amount of oxygenated groups whichenhanced xanthation.

Degradation of ethyl xanthate in flotation residues by hydrogen peroxide

The degradation behavior of ethyl xanthate(EX) salt was the most widely used collector in sulfide mineral flotation and emission of flotation tailings with residual EX was harmful to environment. In this work, hydrogen peroxide(H2O2) was investigated by UV-visible spectroscopy(UV/Vis) at different p H values from 3 to 12. For p H value from 5 to 12, EX was oxidized into ethyl per xanthate(EPX) by H2O2. Then EPX was further oxidized into thiosulfate(TS) salt rather than ethyl thiocarbonate(ETC) and this step was the reaction-limited step. Then depending on p H values, TS was degraded into sulphate and carbonate salts(p H>7) or elemental sulfur(p H<7). The kinetics data show that the degradation rate of EX increases with increasing the H2O2 concentration and is independent on the p H values. Without H2O2, EX is hydrolyzed to carbon disulfide fast at p H value <3.0, but the reaction of hydrolysis is undetectable at p H value >3.0 during test time.

The reversible addition-fragmentation chain transfer(RAFT) miniemulsion polymerization of vinyl acetate mediated by xanthate

乙烯基醋酸盐(休假) 的可逆增加破碎链转移(木排) 微型乳剂聚合由甲基(methoxycarbonothioyl ) 调停了 sulfanyl 醋酸盐(MMSA ) 被执行。结果证明聚合由 AIBN 开始了， KPS 以一个控制方法继续了。KPS 开始的休假的木排微型乳剂聚合在 AIBN 开始的实验比那些显示出更短的抑制时期，更高的繁殖率系数和最后的变换。当单体变换到达了 25% 时，聚合物的多分散性索引(PDI ) 变得宽广，它与在休假的木排微型乳剂的链转移反应有关。

Mechanism of different particle sizes of quartz activated by metallic ion in butyl xanthate solution

To investigate effect of metallic ion activation on different particle sizes of quartz in butyl xanthate solution,six common ions(Pb^(2+),Cu^(2+),Fe^(3+),Fe^(2+),Mg^(2+) and Ca^(2+)) were introduced as activators.The approaches of micro-flotation,adsorption test and zeta potential measurement were adopted to reveal the mechanism of ion activation.The results show that Pb^(2+),Cu^(2+) and Fe^(3+) are effective activators for the flotation of quartz in butyl xanthate solution because of their absorption on activated quartz surface.Average recoveries of fine particles(<37 μm) are greater than those of coarser particles(37-74 μm),suggesting that the former is easier to be activated and more likely to be floated and thus entrained in sulphide concentrate.From another perspective,addition of metallic ions(Pb^(2+),Cu^(2+) and Fe^(3+)) renders zeta potentials move positively,and addition of the same metallic ions and butyl xanthate makes zeta potential drop apparently,which support a mechanism where they adsorb onto quartz surface,resulting in an expected increase in butyl xanthate collector adsorption with a concomitant increase in the flotation recoveries.

PREPARATION OF BAGASSE XANTHATES （BX） AND NICKEL REMOVAL FROM WASTEWATER BY BX

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ON-LINE DETERMINATION OF REMAINED XANTHATE CONCENTRATION IN PULP

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Optical properties of cobalt xanthate films on different substrates

Cobalt isopropyl xanthate thin films （CXTFs） were deposited via chemical bath deposition onto different substrates：commercial glass （CG）, indium tin oxide （ITO）, and poly（methyl methacrylate） （PMM）. Isopropyl xanthate was synthesized according to a method described in the literature. The cobalt nitrate and isopropyl xanthate were mixed in a beaker, which allowed the thin films to be deposited via a simple ion-ion mechanism. The transmission, reflectivity, refractive index, dielectric constant, and optical conductivity were investigated for various thin films coated onto different substrates. An ultraviolet-visible spectrophotometer was used to measure the optical properties of the thin films. The lowest value of the transmission and the highest value of the refractive index were observed for the thin films deposited onto PMM. The structure of the cobalt xanthate was characterized by Fourier transform infrared （FTIR） spectroscopy, which was measured using a Perkin-Elmer Spectrum 400 spectrometer. The stretching vibration of the Co-S bonds was observed at 359 cm^-1 in the FTIR spectrum of the CXTFs.

THE STUDY ON DETERMINATION OF SELENIUM WITH POTASSIUM BUTYL XANTHATE

A simple and fast ultraviolet spectrophotometric method was used to determineselenium (Ⅳ) through the formation, separaion and quantitative determination of potassium butylxanthae -selenium complex. The complex absorbed light sharply at 375 nm. The optimum acidity ofthe complex formation was between pH 3.4 - 4.0. The absorption value was no change in 120 minutesafter the comlex was extracted by Carbon tetraChioride. The sensitivity of the colour reation was 0.2ng cm-2, The content of selenimp (Ⅳ) was within 0-30 μg and linear rclation was good,Y=0.07X＋0.025, relevent coefficient r＝0.9997. A great quantity of I, Cu, Co, the and SO4-2, PO4-3contained in .the Sample had no effect on the results ofdetenninion when seldsum was determined.When content of Fe was over l00gμg/ml and Zn was over 180μg/ml, there was diotance to the determination, but the disturbance was rem0ved by adding EDTA. When making use of the method todetermine containin seldsum additivef Cv =6.85, rate of recovery was 97.2%, wild jujubef;Cv=3.22,rate of recovery was 90. 1%, soil Samlef Cv=4.64, rate of recovery was 86.2%. The method for sensitivity measured was apprtoate to 2, 3-diamino naphthalene (DAN) fluorescence method.

Electrochemical flotation of ethyl xanthate-pyrrhotite system

The flotation behavior of pyrrhotite was investigated by using ethyl xanthate as a collector. The results show that pyrrhotite has good floatability from pH 2 to 11, and poor flotability when pH>12. The reagents adjusting potential are ammonium persulfate （（NH4）2S2O8） and sodium dithionite （Na2S2O4）. The flotation of pyrrhotite is dependent on pulp potential at certain pH value. The potential-pH range for pyrrhotite flotation was established. Cyclic voltammetry and FTIR spectroscopy analysis show that the major adsorption product of ethyl xanthate on pyrrhotite is dixanthogen. The intensity of FTIR signals of dixanthogen adsorbed on pyrrhotite and the anode current of a pyrrhotite electrode and flotation response of pyrrhotite are correlated with pulp potentials.

THE SEPARATION AND DETERMINATION OF XANTHATES USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

Three HPLC methods for the separation and determination of xanthate mixtures are described.The chromatographic behaviours,advantages and application ranges of various:methods have been discussed in detail.A calculation method for determining the results of individual xanthates from the complicated chromatographic peaks of xanthate mixtures is presented.The limits of detection are 0.15-2.0ng.

Essentiality, Fate, Ecotoxicity, and Health Effects of Xanthates and Xanthates Based-Compounds—A Review

Xanthates are organic synthesized substances with a potentially wide range of applications. They may serve as essential components of many compounds or materials that also play a vital role in various industrial and socio-economic processes. Addressing the question of the use of xanthates without considering their toxicity, and their decomposition process and products would be ecologically and healthily less sustainable. To date, related information is still dispersed and less known to the public. Therefore, this work provides a comprehensive overview of the existing information on the essentiality, fate, ecotoxicity, and health effects of xanthates and associated compounds. According to available information from scientific, technical, and professional circles, xanthates are diverse, usually with a carbon chain of two to six carbon atoms. They play a crucial role in the sectors of the mining and mineral processing industry, agriculture, wastewater treatment, metal protection, rubber vulcanization, the pharmaceutical industry, and medicine. Xanthates’ degradation under different factors and mechanisms, which determine their fate in the environment, leads to the formation of toxic substances, mainly carbon disulfide, carbonyl sulfide, hydrogen sulfide, and hydrogen peroxide. Xanthates and xanthates degradation products are seriously hazardous to humans, animals, soil and aquatic organisms, enzymatic system, etc. Simultaneous exposure to xanthates and metals results in the magnification or reduction of their toxicity level, depending on the exposed organisms. Such toxicological dimensions should attract more scientific and public attention for more safe production, use, storage, and disposal of xanthates. Due to the high affinity of xanthates for metal, xanthates-modified compounds are efficient metal chelating agents. Such a property should be explored to develop potentially low-cost and effective alternatives for metal removal and recovery from contaminated media. The same applies to developing appropriate methods for the evaluation and management of the simultaneous presence of xanthates and metals in the environment.

Studies on the Stability of Four－membered Ring Chelates（Ⅳ）──Sulphur Coordinated Xanthate Complexes

Fifteen M(S2COR)n complexes were prepared.According to the data provided by IR,UV-Vis absorption spectrometry and X-ray diffraction,this paper covers the relationship between molecular structures of xanthate complexes and their absorption spectra and a criterion of chelate stability is also proposed.The stability mechanism of xanthate chelates and related rules were investigated.

气溶胶化丁基黄药强化黄铁矿浮选回收机理研究

为分析气溶胶处理丁基黄药对黄铁矿浮选效果的影响规律及其机理,以气溶胶化丁基黄药为捕收剂,进行了黄铁矿单矿物浮选实验,采用电导率、红外光谱及XPS等手段对经气溶胶处理前后的丁基黄药作用的黄铁矿进行表征。结果表明,气溶胶化丁基黄药可显著提高丁基黄药中的有效成分双黄药分子的含量以及黄铁矿的浮选效果,在丁基黄药质量浓度为15 mg/L时,黄铁矿的回收率为57.20%,与未处理相比,黄铁矿回收率提高16.47百分点。气溶胶化处理丁基黄药可以提高溶液中的溶解氧浓度,溶解氧既可促进溶液中双黄药的生成,强化丁基黄药对黄铁矿的捕收效果,又可影响黄铁矿的氧化反应程度,使黄铁矿表面矿物组成发生变化,并且疏水性单质硫的比例增加了7.61百分点,有利于黄铁矿上浮。此外,由于气溶胶化丁基黄药在黄铁矿表面吸附量增大,黄铁矿表面所含疏水基团-C4H9增多,提高了黄铁矿的疏水性。研究结果对气溶胶浮选技术在浮选领域应用有一定的参考意义。

煤气化渣对矿山废水中黄药的吸附性能研究

这是一篇环境工程领域的论文。本论文以煤气化渣作为吸附剂,处理矿山废水中的正丁基钠黄药,通过X射线荧光分析仪、扫描电镜、傅里叶红外光谱仪以及比表面积和孔径分析对煤气化粗渣(CGCS)和煤气化细渣(CGFS)的成分、结构特征和表面性质进行了表征,结果表明,CGFS有着更发达的孔径结构和更大的比表面积。吸附实验研究表明,两种煤气化渣对正丁基钠黄药的吸附均符合Langmuir吸附等温线模型,是自发放热的过程,该吸附过程符合准二级动力学模型,吸附速率常数CGFS>CGCS。其中,CGFS对正丁基钠黄药的吸附性能优于CGCS,其最大吸附量可达181.95 mg/g。

丁基黄原酸盐合成过程起泡问题分析与处理

以金堆城钼业集团有限公司黄原酸盐合成项目为例,针对丁基黄原酸盐合成过程中起泡的问题,采用室内模拟实验和车间生产验证相结合的方式,通过对生产过程、物料性质的分析,查找出了起泡的原因和形成过程,决定采用添加消泡剂的方式来消除泡沫。结果表明:起泡的原因为回收的二硫化碳中带有的有机杂质;1800#、DS-350消泡剂添具有较好的消泡效果,且消泡剂添加量较小,性质较为稳定,对黄原酸盐产品质量和选矿效果无不良影响。