铜捕集法从失效汽车催化剂中回收铂、钯和铑的研究

采用铜捕集法从失效汽车催化剂中回收铂族金属,重点研究了Ca O/Si O2质量比、捕集剂、熔炼温度和时间、以及还原剂对Pt、Pd和Rh回收率的影响。结果表明,在Ca O/Si O2=1.05,Cu O配比35%~40%,还原剂配比6%,熔炼温度1400℃,熔炼时间5 h的条件下,Pt、Pd和Rh回收率分别为98.2%、99.2%和97.6%。     

活性炭陶瓷复合材料的苯吸附特性

用硅藻土及木质活性炭为主要原料制备活性炭陶瓷复合材料,通过含炭量、碘吸附值、体积密度、气孔率和抗压强度测试确定最佳制备工艺条件。探讨该活性炭陶瓷复合材料对苯的吸附特性影响,对比分析了活性炭不同添加量、不同烧结温度及不同环境温度对材料苯吸附性能的影响。结果表明适宜的硅藻土与活性炭比值为7∶3,烧成温度为800℃,此时该材料的气孔率达到52.48%,体积密度为1.067 g/cm3,抗压强度为10.466 MPa,碘吸附值为291.24 mg/g,含炭量为25.62%,苯吸附率为9.56%,比表面积为290.72 m2/g。活性炭陶瓷复合材料的苯醛吸附率随着活性炭含量的增加明显加大,但受外界环境温度影响较小。     

磁性Fe3O4/活性炭对电镀废水中Cr(Ⅵ)吸附性能的研究

目的获得吸附性能、磁分离性能和再生性能较佳的磁性Fe_3O_4/活性炭吸附剂(MAC)。方法通过化学共沉淀法制备出磁性Fe_3O_4/活性炭吸附剂。采用X-射线衍射仪(XRD)和傅里叶变换红外光谱仪(FTIR)对活性炭进行表征。使用磁性Fe_3O_4/活性炭吸附电镀废水中的Cr(Ⅵ),考察吸附剂用量、吸附pH值和吸附时间对吸附性能的影响,并研究了吸附动力学模型。利用磁铁对磁性Fe_3O_4/活性炭进行了回收。结果制备的磁性Fe_3O_4/活性炭中含有纯度较高的立方相磁性Fe_3O_4粒子。在温度为25℃、pH=3、吸附时间为120 min、吸附剂用量为0.15 g时,对Cr(Ⅵ)的去除率最高,达到了97.44%,吸附动力学符合拟二级动力学模型。电镀废水中共存阳离子会使吸附性能增强,共存阴离子会使吸附性能降低。磁性Fe_3O_4/活性炭的回收率达93.58%,6次解吸-再生后,吸附量仍较高,为27.17 mg/g。结论磁性Fe_3O_4/活性炭吸附剂对电镀废水中的Cr(Ⅵ)具有较高的去除率,吸附剂回收方法简单,回收率高,具有较好的应用前景。     

粉煤灰“一步酸溶法”蒸发母液焙烧渣中锂的水浸特性

粉煤灰“一步酸溶法”提取氧化铝工艺过程中,蒸发结晶工序析出氯化铝晶体后,蒸发母液中锂的含量高达329 mg/L以上,且经过处理后可进一步浓缩,富集达到2.2 g/L,具有很高的提取价值。研究发现蒸发母液通过焙烧浸出可实现锂的浸出率>80%,而主要元素铝的浸出率非常低,从而将锂和铝分离,最终实现锂的提取。文章分别考察了蒸发母液焙烧渣中的锂在不同条件下的浸出特性,研究结果表明,当焙烧温度400℃、焙烧时间20 min时,使用纯水在浸出温度为80℃、浸出时间2.5 h、液固比为9∶1条件下,锂的浸出率可达到85%,而铝的浸出率近似为0。     

改性活性炭吸附铂和钯的研究

通过研究活性炭吸附Pt和Pd的影响因素，找到了吸附的最佳条件：Dim116炭（氨气活化）吸附Pd，pH1．5－11，[CN^-]＜0．5或[Cl^-]＜50；TU60炭（氢氧化钠活化）吸附Pt，pH2－11，[CN^-]＜0．5或[Cl^-]＜50。解吸的最佳条件：对于Dim116炭，温度90℃，[NaCN]＝1％，[NaOH]＝2％；对于TU60炭，温度90℃，[C2H4O2]＝2％，[HNO3]＝1％。提出了用活性炭从氯化液、氰化液中吸附Pt和Pd的工艺流程。     

H2SO4中丙炔醇复配缓蚀剂对碳钢的缓蚀作用

目的探究不同温度下丙炔醇、KI及其复配对Q235碳钢和N80钢片在10%(质量分数)硫酸中的缓蚀性能。方法采用静态失重法和电化学方法,60℃下测定酸液中的单剂对Q235碳钢的缓蚀性,然后对二者进行复配研究。优化配比后升高实验温度,探究高温下不同配比在酸液中对N80钢片的缓蚀性能。根据吸附等温模型和腐蚀动力学对缓蚀机理进行初步探讨。结果失重法表明,60℃时单独使用丙炔醇、KI,当质量浓度分别为120、1000 mg/L时,对Q235碳钢的缓蚀率均达到90%,两者的使用浓度较高。复配后得到两个优选配比,配比A为丙炔醇18 mg/L+KI 250 mg/L,配比B为丙炔醇15 mg/L+KI 300 mg/L,配比A、B的缓蚀率均高达98%。配比A、B的缓蚀率均随温度升高而降低,配比A在80℃酸液中对N80的缓蚀率为93%,配比B在100℃酸液中的缓蚀率为73%。结论复配后缓蚀剂的使用量均降低,且在一定高温下具有良好的缓蚀性能,丙炔醇和KI有较好的协同作用。电化学的实验结果与失重法相一致,丙炔醇和复配剂为混合型缓蚀剂。缓蚀剂在金属表面的吸附为化学吸附,符合Langmuir吸附等温模型。     

大肠杆菌对铂(IV)的吸附特性及行为表征

比较了10种菌株对纯溶液中铂(IV)的吸附效果,优选出大肠杆菌作为吸附剂,并对其吸附行为进行了表征和研究。吸附动力学及颗粒内扩散模型表明,大肠杆菌对铂(IV)的吸附过程经历了快速的表面吸附和缓慢吸收2个阶段,并可在60 min内达到吸附平衡;吸附后的SEM、TEM形貌表征显示,大肠杆菌菌体细胞发生形变,皱缩并团聚;XPS结果显示,部分铂(IV)转化为铂(II),表明吸附过程中发生了还原。在25℃、pH=7.0、6 h的条件下,大肠杆菌对初始浓度为100 mg/L的Pt(IV)溶液的吸附率为96.66%。     

石墨炉原子吸收测定岩石样品中超痕量铂

样品分解后,用超低灰分活性炭吸附ψ为5%～15%HCl溶液中的Pt,活性炭灰化,灰分用王水溶解后,在10%HCl溶液中用GF-AAS方法测定岩石样品中超痕量铂.作者研究了测定酸度、介质及石墨炉灰化温度、原子化温度等因素对吸光度的影响.在选定条件下测定方法的检出限达到0.1×10-9,精密度(SD,n=12)5%～9%,经国家一级标准物质分析验证,结果吻合.     

选铁尾矿和钛精矿直接还原-磁选工艺回收铁实验研究

针对铁品位较低的选铁尾矿和钛精矿,探索了直接还原-磁选回收铁的工艺。综合考察了配碳量、焙烧温度、保温时间和冷却方式对直接还原金属化率的影响,找出了实验最优指标。通过XRD和化学分析讨论了不同焙烧温度下还原过程中物相的变化。结果表明:选铁尾矿中二价铁主要存在的物相(Fe,Mg)(Ti,Fe)O3在1300℃下较充分的被还原为金属铁。钛精矿中三价铁主要存在的物相Fe2TiO5在1300℃下较充分的还原为金属铁。在配碳量为6.29%,焙烧温度1300℃,保温时间1.0 h的最优条件下,选铁尾矿铁回收率达到80%,铁品位58%。在配碳量为10.36%,焙烧温度1300℃,保温时间1 h条件下,钛精矿铁回收率达到95%,铁品位78%。     

钯碳催化剂工业废水处理研究

分别采用活性炭吸附法、絮凝剂吸附法和氧化法处理钯碳催化剂工业废水,重点考察了试剂加入量及处理时间对废水化学需氧量(COD)的影响,其中氯酸钠氧化法具有最佳处理效果。正交试验表明,氯酸钠处理催化剂废水COD的影响因素中,氯酸钠加入量影响最为显著,优选的条件下,在50 mL废水中加入氯酸钠2.5 g/L,在40℃以200 r/min搅拌处理1 h,可以使废水COD去除率达到87.6%,达到排放标准。     

A sorbent of expanded rice husk powder for removal of uranyl ion from aqueous solution

A novel sorbent for the removal of uranyl ion was prepared by expanded rice husk powder. Batch adsorption experiments were performed on factors of p H,temperature, initial uranyl ion concentration, adsorbent dosage and contact time to evaluate the adsorption capacity. The results show that the saturation adsorption capacity is 5.7 mgág~(-1) using expanded rice husk powder treating uranyl ion aqueous solution(80 mgáL~(-1)) for 24 h at 25 °C with initial pH3. Adsorption process could be well described by Langmuir isotherm model. The adsorption kinetic data are fitted well with pseudo-second-order model. The results obtained show that expanded rice husk adsorbent is a promising adsorbent for the removal of uranium from aqueous solutions.     

Hydrogen adsorption on model nanoporous carbon adsorbents

Hydrogen adsorption on model nanoporous adsorbents with slit-like micropores of 0.538, 0.878, and 1.218 nm width, which were obtained by successively eliminating one, two, and three layers of hexagonal carbon from a graphite structure treated as a model cell, is estimated. The Dubinin theory of volume pore filling and the linearity of adsorption isosters are used. Hydrogen adsorption isotherms are calculated at temperatures of 20, 33, 77, 200, 300, and 400 K and pressures up to 20 MPa for the structures with mono-and bilayer carbon walls. The maximum hydrogen adsorption for the AC35 structure at a pressure of 20 MPa and a temperature of 300 K was 7.9 wt %. The effect of parameters of the porous adsorbent structure on the temperature dependence of the hydrogen adsorption is discussed. Original Russian Text ? A.A. Fomkin, V.A. Sinitsyn, 2008, published in Zashchita Metallov, 2008, Vol. 44, No. 2, pp. 163–169.     

Adsorption-induced deformation of AUK microporous carbon adsorbent in adsorption of <Emphasis Type="Italic">n</Emphasis>-pentane

The isotherms of the relative linear adsorption deformation of AUK microporous carbon adsorbent are measured during the n-pentane adsorption within the pressure range of 1 Pa to 50 kPa and at temperatures of 243, 273, 293, 313, 353, and 393 K. The curves of adsorption deformation have similar behavior within the whole range of investigated temperatures. Except for the initial pressure range p < 400 Pa, the adsorption deformation increases as pressure grows and reduces as temperature grows. The effects of adsorption deformation manifest extremely weakly at pressures of less than 400 Pa. Nevertheless, in this pressure range, at temperatures below 350 K, the initial compression of adsorbent (0.01%) is observed, which increases as temperature reduces. At higher temperatures, the sharp initial adsorbent expansion by 0.002% is observed, which transfers them to a narrow region of deformation constancy. Beyond this region, the adsorbent expands in all temperature ranges as the pressure increases.     

柠檬酸活化赤泥对亚甲基蓝染料废水的吸附净化作用

采用一种活化赤泥吸附剂用于水溶液中亚甲基蓝的吸附净化.考察吸附剂用量、pH值、亚甲基蓝浓度、吸附温度和吸附时间对活化赤泥吸附性能的影响规律.结果表明:采用稀柠檬酸活化处理可显著提高赤泥对染料分子的吸附效率;吸附率随吸附剂用量增加而增加,随初始亚甲基蓝浓度和温度升高而降低;测得活化赤泥对亚甲基蓝的最大吸附容量为30 mg/g,吸附过程符合Langmuir等温吸附模型;吸附动力学过程可用准二级动力学方程描述,计算出吸附过程的表观活化能为9.88 kJ/mol.对吸附过程焓和熵值的计算结果表明,活化赤泥对水溶液中亚甲基蓝染料的吸附是一个自发的放热过程.     

Nitrogen adsorption by microporous adsorbents in the range of high pressures and supercritical temperatures

The nitrogen adsorption isotherms for the AUK microporous carbon adsorbent are measured at pressures of 1 Pa to 6 MPa and temperature of 177.7–393 K. In terms of the adsorption isotherms, in the same range of pressures and temperatures, the nitrogen adsorption isosteres are calculated. The resultant dependences are adequately approximated by linear functions. By the adsorption isosteres, the dependences of differential molar isosteric heat of adsorption on the value of adsorption and temperature are plotted. The results are compared with the literature data on nitrogen adsorption by zeolite NaX and activated carbon SKT.     

Enhanced Cu(Ⅱ) adsorption by orange peel modified with sodium hydroxide

Copper adsorption by orange peel, which was chemically modified with sodium hydroxide, was investigated. The adsorbent was characterized using surface area analyzer, infrared spectroscopy and scanning electron microscopy. Total negative charge and zeta potentials on the adsorbent surface were determined. Equilibrium isotherms and kinetics were obtained and the effects of solution pH value, adsorbent concentration and temperature were studied in batch experiments. Column experiments were performed to study practical applicability, and breakthrough curves were obtained. Equilibrium is well described by Langmuir and Freundlich isotherms, and kinetics is found to fit pseudo-second order type adsorption kinetics. According to Langmuir equation, the maximum adsorption capacity for Cu(II) is 50.25 mg/g at pH value of 5.3. The results show additional chemical modification of the adsorbent by NaOH and the increased adsorption capacity.     

Adsorption and reduction of platinum(IV) chloride complex ions on activated carbon

The adsorption kinetics of platinum(IV) chloride complex ions on the activated carbon Norit GF40 was investigated. Experiments were carried out at different initial concentrations of Pt(IV) chloride complex ions, temperature, rate of mixing and pH. It was found that the value of activation energy of the studied process is equal to 19.7 kJ/mol. From the ICP MS analysis it was confirmed that platinum ions (Pt(IV) and Pt(II)) are removed from the solution due to the adsorption and are further reduced to the metallic state. Such mechanism was confirmed by XPS analysis which showed that on the carbon surface three forms of platinum species, i.e. Pt(0), Pt(II) and Pt(IV), exist. The presence of platinum in the solution at different oxidation states was also confirmed spectrophotometrically by identification of their characteristic absorption bands. The metallic form of Pt present on the surface of activated carbon was observed in the form of small spherical islands with the diameter not exceeding 500 nm. Those islands consist of smaller, flake-shape particles with a thickness of about 35 nm.     

Adsorption of phenol from aqueous solution by a hierarchical micro-nano porous carbon material

A hierarchical micro-nano porous carbon material (MNC) was prepared using expanded graphite (EG), sucrose, and phosphoric acid as raw materials, followed by sucrose-phosphoric acid solution impregnation, solidification, carbonization and activation. Nitrogen adsorption and mercury porosimetry show that mixed nanopores and micropores coexist in MNC with a high specific surface area of 1978 m2·g-1 and a total pore volume of 0.99 cm3·g-1. In addition, the MNC is found to consist of EG and activated carbon with...