Promotion effect of KOH on preparation of dissolved Fe(Ⅵ)

In order to improve the yield and stability of ferrate in solution, dissolved Fe(Ⅵ) prepared with NaOH and KOH respectively was compared in this study. The results showed that KOH is more suitable than NaOH for the preparation of dissolved Fe(Ⅵ) at temperature over 50 ℃. It is found that the dissolved Fe(Ⅵ) prepared with KOH increases quickly at first, and then slowly with the increasing concentrations of OH-and ClO-, while it increases rapidly at first and then decreases rapidly with the increasing dosage of Fe(NO3)3·9H2O. These results are different from that prepared with NaOH. It can be explained that solid K2FeO4 salts can be formed in KOH solution, and it will lower the Fe(Ⅵ) concentration, counteract the decomposition of Fe(Ⅵ), and improve the yield of Fe(Ⅵ). The maximum ferrate concentration is 0.163 mol/L obtained by 100 g/L Fe(NO3)3·9H2O and 6.16 mol/L KOH at 65 ℃. The stability of Fe(VI) is greatly improved due to the hypochlorite existed in the dissolved ferrate, and only 24% Fe(Ⅵ) has been decomposed after 16 d for 1 mmol/L Fe(Ⅵ) at 25 ℃.     

Promotion effect of KOH on preparation of dissolved Fe (VI)

In order to improve the yield and stability of ferrate in solution, dissolved Fe (VI) prepared with NaOH and KOH respectively was compared in this study. The results showed that KOH is more suitable than NaOH for the preparation of dissolved Fe(VI) at temperature over 50 ℃. It is found that the dissolved Fe(VI)prepared with KOH increases quickly at first, and then slowly with the increasing concentrations of OH- and ClO~- , while it increases rapidly at first and then decreases rapidly with the increasing dosage of Fe(NO_3)_3·9H_2O. These results are different from that prepared with NaOH. It can be explained that solid K_2 FeO_4 salts can be formed in KOH solution, and it will lower the Fe (VI) concentration, counteract the decomposition of Fe(VI), and improve the yield of Fe(VI). The maximum ferrate concentration is 0. 163 mol/L obtained by 100 g/L Fe(NO_3)_3· 9H_2O and 6. 16 moL/L KOH at 65℃. The stability of Fe(VI) is greatly improved due to the hypochlorite existed in the dissolved ferrate, and only 24% Fe(VI) has been decomposed after 16 d for 1 mmol/L Fe(VI) at 25 ℃.     

Fe(Ⅲ)对染料废水的脱色作用

利用FeCl3.6H2O作为无机絮凝剂和H2O2作为氧化剂对活性蓝染料废水进行了脱色实验。通过改变pH、絮凝剂的用量和高分子电解质的种类,寻求最佳的反应条件。实验结果表明,FeCl3.6H2O的浓度为100 mg.L-1,废水的pH=7时,可以达到100%的脱色效果。同时,阳离子型高分子电解质能有效的增加絮凝剂的脱色效率。当Fe(II)和H2O2在最佳的摩尔比条件下,其初始浓度对脱色率也会产生一定的影响。     

二元氧化剂合成簇状聚苯胺纳米棒及其电学性质

通过自组装法采用二元氧化剂合成了簇状聚苯胺纳米棒,用IR、XRD、SEM和EDX等测试手段对产物的结构和性质进行了表征,讨论了氧化剂对产物形貌及性质的影响和反应的形成机理。结果表明,当苯胺单体与氧化剂K2Cr2O7的浓度比为1∶1时,产物形成的簇状形貌最好。     

Epoxidation of styrene over mesoporous Zr–Mn-MCM-41

Epoxidation of styrene with t-butyl hydroperoxide (TBHP) as an oxidizing agent has been conducted under liquid phase reaction conditions over Zr–Mn-MCM-41 with different n_Si/(n_Zr + n_Mn) ratios and Mn-MCM-41(31) catalysts for selective synthesis of styrene oxide. The influences of various reaction parameters such as temperature, time, oxidants, and solvents, styrene to TBHP mmol ratios and acetonitrile (MeCN) to N,N-dimethylformamide (DMF) volume ratios on the conversion of styrene and the selectivity of styrene oxide have also been studied. With the decrease of the n_Si/(n_Zr + n_Mn) ratios of Zr–Mn-MCM-41 catalysts from 327 to 49, the conversion of styrene as well as the yield and selectivity of styrene oxide increase due to the increase of the number of Lewis acid sites on the surface of catalysts. Moreover, the conversion and selectivity in Zr–Mn-MCM-41(49) is higher as compared to that of Mn-MCM-41(31). The Zr–Mn-MCM-41(49) is found to be reusable for the epoxidation of styrene with TBHP for selective synthesis of styrene oxide.     

钴内标熔融制样-X射线荧光光谱法分析铁矿石中主次成分

应用熔融制样-X射线荧光光谱法(XRF) 测定铁矿石中各主量元素,直接熔制铁矿石样片,由于受到各种基体效应影响,TFe含量结果不稳;为了得到稳定可靠的TFe含量,一般采用Co内标法,即在熔制铁矿石样片时加入定量的Co元素作为Fe元素的内标;但由于Co₂O₃在高温下易转变为CoO,会造成铂-金坩埚腐蚀。采用为Co₂O₃在被熔入Li的硼酸盐熔剂前持续提供氧化环境的方式,保持Co元素在整个熔融制样过程中不以CoO形式出现,解决了铂-金坩埚的腐蚀问题。通过试验确定优化的熔融条件:于1 050 ℃熔融温度下旋转摇摆7 min,稀释比为1∶10,以KBr为脱模剂。铁矿石中各主次成分校准曲线的相关系数均达到0.997以上。对铁矿石标准样品进行精密度考察,各成分测定结果的相对标准偏差(RSD,n=12)均不大于6.7%;正确度结果表明,标准样品和实际样品的测定值分别与认定值及国标湿法值相一致。     

膨胀石墨的化学氧化法制备研究进展

通过对氧化剂、插层剂、水洗方式和膨化方式的分析,综述了化学氧化法制备膨胀石墨的研究进展及遵循思路。提出了下一步的研究方向:低硫乃至无硫、低污染、高膨胀体积和高抗氧化能力。     

硫氰酸铵法提金工艺研究

以四川某硫化物包裹型金矿石精金砂为原料, 对比研究了氰化法和硫氰酸铵法的提金效果, 考察了氧化剂Fe³⁺和MnO₂在硫氰酸铵浸金工艺中的作用和特点, 并对氰化法和硫氰酸铵法的浸出机理进行了初步探讨和分析。结果表明, 硫氰酸铵法比氰化法有更好的提金效率; 用Fe³⁺作氧化剂的硫氰酸铵浸金法提金效率可达96%。     

乙蒜素合成新工艺研究

以乙硫醇为原料,KI为催化剂,对乙蒜素合成工艺进行了研究,尤其是对关键中间体二乙基二硫醚的合成关键因素优化和探讨.结果表明,投料比为M乙硫醇:MKI:M30％双氧水=1:0.02:0.6,滴加双氧水时间为3 h,滴加完毕后继续反应20 min,其收率可达85％以上,纯度大于99％;而投料比M二乙基二硫醚:M41％稀硝酸...     

矿物浮选分离硫化铜、硫化锌的研究进展

随着我国对金属铜、锌资源需求的不断增加,有效的处理铜、锌矿石及对两者的高效利用对我国的经济建设有着极大的意义。硫化铜矿以黄铜矿为主,通常与硫化锌矿中的闪锌矿伴生,因此对两者进行分离是选矿研究中的一个热点。由于磨矿过程中黄铜矿溶解出的铜离子会对闪锌矿造成明显的活化效果,使得两者可浮性相近,这是导致铜、锌矿物分离困难的主要原因。对于铜锌硫化矿浮选分离当前的研究热点主要为抑锌浮铜,但在闪锌矿抑制剂研究方面深度不够,必须进一步研究不同抑制剂的抑制机理,从而更加清楚地调控矿浆环境及合理改变矿物的表面性质,以此增强抑制剂对闪锌矿的选择性。而发展新型氧化型药剂、外界物理化学方法改性以及研究抑铜浮锌的新方法是今后铜锌浮选分离的研究方向。