Thermodynamic study on reaction path of Hg(Ⅱ) with S(Ⅱ) in solution

The mercury sulfidation experiments were conducted in the pH range from 1 to 13.The results show that Hg(Ⅱ) reacted with equimolar S(Ⅱ) has the lowest remained Hg(Ⅱ) concentration(9.7 μg/L) at pH 1.0 and the highest remained concentration(940.8 μg/L) at pH 13.0.Meanwhile,the changes of pH values were monitored exactly,which reveal that solution pH values change when mixing the same pH value solutions of HgCl2 and Na2S.In order to explain the phenomena and determine the reaction paths of Hg(Ⅱ) reacting with S(Ⅱ) in the solution,the concerned thermodynamics was studied.Species of S(Ⅱ)-H2O system and Hg(Ⅱ)-H2O system at different pH values were calculated,and then the species distribution diagrams of S(Ⅱ)-H2O system,Hg(Ⅱ)-H2O system and Hg(Ⅱ)-Cl--OH--H2O system were drawn.Combining the experimental data and thermodynamic calculation,the mechanism of Hg(Ⅱ) reacting with S(Ⅱ) was deduced.The results indicate that different species of S(Ⅱ) and Hg(Ⅱ) have the diverse reaction paths to form HgS precipitate at different pH values and the standard Gibbs free energies change(△r GmΘ)of those equations are also calculated,which can provide a guidance for mercury-containing wastewater treatment with Na2S.     

Zn（Ⅱ）-NaOH-H2O体系中锌溶解平衡模型的构建

本文利用电算指数法及平衡法对Zn（Ⅱ）-NaOH-H2O体系热力学进行了深入研究,揭示了在氢氧化钠浓度在0-300 g/L范围内,锌的分布形式及溶解规律,构建了锌在氢氧化钠溶液中的溶解平衡模型,并对热力学计算结果进行实验验证和差异分析.结果表明：锌溶解平衡浓度计算值与实验值的相对偏差的绝对平均值为0.1298%,这说明热力学模型是正确的,所选数据的准确性较好.     

类Fenton试剂法（Fe-H_2O_2）处理餐饮油脂废水

为了处理餐饮油脂废水中难以生物降解的有机物,采用类Fenton试剂（Fe-H2O2）对其进行处理,分别考察了pH值、反应时间、反应温度、H2O2投加量和Fe投加量对CODCr和动植物油去除率的影响,总结得出了H2O2投加量的系列计算公式。结果表明：废水初始CODCr浓度为1 633.52 mg/L,油脂值为349.58 mg/L时,在pH值为2、反应时间30 min、反应温度60℃、H2O2（30%）投加量为5 mL、nH2O2∶nFe=6∶1的最优条件下,CODCr和动植物油的去除率分别达到91.2%和96.47%。     

A study on Cr（VI） reduction from aqueous solutions by bauxite

The reduction of Cr（Ⅵ） in aqueous solution by using bauxite ore was investigated.Experimental results for Cr（Ⅵ）reduction in aqueous solution depending on some factors such as time,sulfuric acid amount,bauxite dosage,initial Cr（Ⅵ）concentration,formic acid concentration,daylight and temperature were presented.The obtained results show that sulfuric acid amount,bauxite dosage and initial Cr（Ⅵ） concentration of solution are most effective parameters on the reduction process.Also,it has been found that the 60 g/L of bauxite dosage is sufficient to reduce up to 100% of Cr（Ⅵ） from acidic solution under the condition of low initial Cr（Ⅵ） mass concentrations such as 10 mg/L.The reduction reaction is completed within 30 min at 25 ℃ under the experimental conditions：bauxite dosage of 60 g/L,amount of sulfuric acid 40-60 stoichiometric and initial mass concentration of Cr（Ⅵ）,10 mg/L.It was determined that reduction percentage is decreasing with increasing initial Cr（Ⅵ） concentration.The chemical oxygen demand of bauxite ore was found to be 26 mg COD/g.     

Effects of H3PO4 and Ca（H2PO4）2 on mechanical properties and water resistance of thermally decomposed magnesium oxychloride cement

The effects of H3PO4 and Ca（H2PO4）2 on compressive strength, water resistance, hydration process of thermally decomposed magnesium oxychloride cement （TDMOC） pastes were studied. The mineral composition, hydration products and hydration heat release were analyzed by XRD, FT-IR, SEM and TAM air isothermal calorimeter, etc. After being modified by H3PO4 and Ca（HzPO4）2, the properties of the TDMOC are improved obviously. The compressive strength increases from 14.8 MPa to 48.1 MPa and 37.1 MPa, respectively. The strength retention coefficient （Kn） increases from 0.38 to 0.99 and 0.94, respectively. The 24 h hydration heat release decreases by 10% and 4% and the time of hydration peak appearing is delayed from 1 h to about 10 h. The XRD, FT-IR and SEM results show that the main composition is 5Mg（OH）z＇MgCIz＇8H20 in the modified TDMOC pastes. The possible mechanism for the strength enhancement was discussed. The purposes are to extend the potential applications of the salt lake magnesium resources and to improve the mechanical properties of TDMOC.     

Influence of coexisting substances on the photodegradation behaviors of 17α-ethinylestradiol （EE2） in the UV/H2O2 process

The batch photodegradation reactor was used to investigate the influence of the common coexisting substances in wastewater,such as H+,anions (HCO3-,Cl-and NO3-) and organic compounds (methanol and bisphenol A),on the photodegradation behaviors of EE2 in the UV/H2O2 process.The results indicated that the addition of coexisting substances can influence the photodegradation behaviors of EE2 and it also follows the first-order kinetics.The acidic (pH 2-4) and alkaline (pH 10-12) medium benefit the photodegradation of EE2,but the photodegradation rate constant of EE2 keeps almost constant in the pH value of 4-10.The addition of anions,such as HCO3-,Cl-and NO3-,can inhibit the photodegradation of EE2,and the rate constant has a negative linear relationship with the concentration of the anions.However,the reduction degrees vary with the anions kinds,and the inhibition effect of the three anions is in the order of HCO3->NO3->Cl-.Addition of 5 mg/L methanol and bisphenol A can reduce the photodegradation rate constant of EE2by 84.31% and 72%,respectively.By comparison,the retardant effect of methanol is much more evident.In the studied concentrations range,the photodegradation rate constant of EE2 is the unary quadratic function of the organic compounds concentrations.     

电生H2O2协同电解絮凝法处理餐饮废水实验研究

采用电生H2O2协同电解絮凝法处理餐饮废水，研究了废水初始浓度、电解时间、电压、电极材料、pH等因素对降解餐饮废水的影响．结果表明，进水CODCr在1200mg／L以内、pH值为中性的餐饮废水，在10V电压、电磁搅拌、曝气条件下，电解15min后，COD去除率在80％以上．该法利用了铝阳极反应生成的絮凝剂Al(OH)3和阴极上电合成的H2O2对有机物的去除作用，同时阳极产生的H^ 与阴极产生的OH^-中和又促进了两极的反应，使有机物降解更彻底．     

F-D算法求解最短路径

分析Floyd算法与Dijkstra算法的基本思想,将二者结合起来,给出一种新的求最短路径的优化算法——F-D算法,用F-D算法求解基于GIS的电力通信线路最短路径,并在约束条件下对所求最短路径进行修正,验证了F-D算法的先进性和高效性,优化了通信线路的拓扑,实际应用意义重大。     

Sorption of Pb(II) from aqueous solution by konjac glucomannan beads

Konjac glucomannan beads have been investigated as metal biosorbent for Pb(II) from aqueous solu-tions. The effect of contact time, solution pH, initial metal concentration, and desorption were studied in batch experiments at 20℃±2℃. Maximum mental sorption was found to occur at initial pH 4.0―5.5. Kinetic studies revealed that the initial uptake was rapid and equilibrium was established in 3 h and that the data followed the prseudo-second order reaction. The equilibrium sorption data at initial pH 4.0 were described by the Langmuir and Freundlich isotherm models; however, Langmuir isotherm model has been found to provide the best correlation. The highest value of Langmuir maximum uptake (qmax) was found to be 105.71 mg·g-1. Similar Freundlich empirical constant (KF) was obtained to be 1.98 for lead. Adsorption-complexation may be involved in the sorption process of lead. Desorption experi- ments showed evidence that after two contacts neither HCl nor EDTA solutions were able to desorb lead from the konjac glucomannan beads, but the desorbtion efficacy of HCl solution was higher than EDTA solution. The results obtained show that konjac glucomannan beads may be used for the treat-ment of wastewater contaminated with lead.     

Synthesis and coloring properties of Cd(S1-xSex)pigments by precipitate-hydrothermal method

Cd(S1-xSex) pigments (red to yellow) were synthesized by precipitate-hydrothermal method.The structure,morphology and hue of the powder were characterized by X-ray diffractometry (XRD),scanning electron microscopy (SEM),energy dispersive X-ray spectroscopy (EDAX) and CIE chromaticity.The optimum synthesis conditions were obtained and reaction mechanism was further analyzed as well.The results show that molar ratio of S to Se,pH value and hydrothermal reaction conditions have great effects on the hues of the pigments.Pigments with vivid hues are obtained under the conditions that pH value is about 13.0,hydrothermal reaction condition is at 140 ℃ for 4 h or at 160 ℃ for 6 h.The reaction mechanism is that Se2- of Cd(S1-xSex)substitutes S2- of CdS and then forms a continuous solid solution.     

CO_2加氢制低碳烯烃反应中引入耦合反应的影响研究

针对CO2加氢制低碳烯烃反应的特点,考虑将气化反应引入到CO2加氢制低碳烯烃反应中。对无煤粉参与反应和有煤粉参与反应两种情况下的CO2加氢反应进行了热力学分析。采用总吉布斯自由能最小法计算得到不同温度下反应体系平衡组成及反应物的平衡转化率。对比两种情况下的计算结果表明,引入气化反应,平衡组成中烯烃含量和反应物H2转化率都提高了,而产物中H2O的含量降低了,表明有更多的氢储存到烃中,但反应物CO2的转化率降低了。此外,通过实验得到两种情况下CO2加氢反应产物分布,实验结果表明有煤粉参与的反应,烯烃选择性更高,但CO2转化率降低了,这与热力学分析所得结论一致。     

负载水相催化剂(SAPC)在Heck反应中的催化性能

以氯化钯(PdCl2)/硅胶负载水相催化剂(SAPC)为对象,研究了浸渍法制备的SAPC在碘代苯和丙烯酸Heck芳基化反应合成肉桂酸的催化活性.主要考察了SAPC中水的质量分数,PdCl2负载量,反应温度,反应时间等因素对肉桂酸产率的影响,结果表明,SAPC催化活性与均相反应结果极其相近;当负载量为7.0 mg-PdCl2/g-硅胶,水的质量分数为7.0%,反应温度95℃,反应时间6 h时,肉桂酸产率较高,达到86.1%.从催化剂活性组分流失研究结果可知,经过简单固液分离得到的催化剂再浸渍后可再循环使用,但催化剂活性下降可达10%,其原因可能是PdCl2在溶剂中的溶解流失、水的蒸发等原因引起.     

X60在硫化氢环境下疲劳裂纹扩展速率研究

采用中心裂纹板试样及TS4-12MC电阻测量片测定了X60材料埋弧焊焊缝在空气和不同浓度H2S水溶液环境下的腐蚀疲劳裂纹扩展速率。由于疲劳过程的复杂性,试样工作区域又在焊缝处,所以试验的最终结果具有一定分散性。试验结果表明,H2S水溶液环境下的疲劳裂纹扩展速率明显比空气中的快,并且有随着H2S溶液浓度增加而变快的趋势。     

爆炸消应处理在武钢高炉热风炉上的应用

介绍了消除焊接残余应力爆炸处理技术在武钢高炉热风炉上的成功应用．爆炸处理后焊接残余应力下降60％以上，残余应力水平满足设计要求，结构运行良好．     

钢包渣中的氧化物与氮反应的热力学研究(二)

通过对钢包渣中V2O5,Nb2O5,La2O3等氧化物与氮反应的理论计算可知:在低压下,向还原性钢包渣中添加氧化物(V2O5,Nb2O5,La2O3),这些氧化物都可以与钢液中氮反应,对钢液脱氮有利;其中V2O5对钢液脱氮的促进作用明显大于其它两种氧化物;钢液在深脱氧的情况下,熔渣中这些氧化物都促进钢液脱氮.     

纳滤膜在盐化工废水处理中的应用研究

采用陶氏NF270-4040纳滤膜对盐化工废水进行脱盐的试验研究,考察了操作压力、温度、进水流量、进水pH值对纳滤膜脱盐率、Ca2+截留率和膜通量的影响,并根据非平衡热力学模型对试验结果进行了分析.结果表明:在操作压力为0.2~1.2 MPa、温度为15~30℃、进水流量为6~16 L/min、pH值为4.0~9.0的条件下,脱盐率、Ca2+截留率随着操作压力的升高而升高,随着温度的升高而降低,膜通量随着操作压力、温度的升高而升高,但脱盐率、Ca2+截留率和膜通量受进水流量和pH值影响不大.     

酸性矿山废水S(-II)对含铬和钼施氏矿物溶解与相转变的影响

施氏矿物对酸性矿山废水中重金属的环境行为有一定的制约作用,但随着环境条件的改变,施氏矿物可能会溶解并产生相转变,从而引起重金属的再次释放。采用快速化学法合成不同铬、钼含量的重金属负载型施氏矿物,并采用流动柱法结合XRD、SEM及XPS等表征手段探究酸性矿山废水还原性S(-II)对负载不同含量铬和钼的施氏矿物溶解与相转变的影响。结果表明：淋滤液中重金属和硫离子浓度随淋洗天数的增加而下降,并随铬和钼负载含量的增加而明显下降,下降量大小顺序为Sch>0.1Mo0.06Cr-Sch>0.2Mo0.09Cr-Sch,而重金属铬和钼的释放过程以零级动力学模型描述最佳。XRD和XPS表征结果表明：未负载重金属施氏矿物处理组反应后产物主要为针铁矿,而负载的重金属在一定程度上提高了施氏矿物的稳定性,延迟了矿物的相转变。