羟基铁铝柱撑膨润土在含铬废水处理中的应用

以FeCl3、AlCl3和Na2CO3配制柱化剂,以钠基膨润土为原料,制备了羟基铁铝柱撑膨润土,并研究了其作为絮凝剂对含Cr(Ⅵ)废水的处理效果.结果表明:羟基铁铝柱撑膨润土对Cr(Ⅵ)有很好的去除效果,羟基铁铝柱撑膨润土投加量、pH及搅拌时间对Cr(Ⅵ)的吸附有较明显的影响,其中羟基铁铝柱撑膨润土投加量的影响最为显著...     

Swelling,compression and tribological behaviors of bentonite‐modified polyacrylate‐type hydrogels

Hydrogel was synthesized from acrylamide and 2‐acryloylamido‐2‐methylpropanesulfonic acid monomers (ratio: 50/50 wt %) and crosslinked with 0.25 wt % of methylene‐bisacrylamide. This hydrogel was also modified by adding 4 wt % of sodium bentonite (NB). Selected properties of the hydrogels with and without NB were investigated and compared. Their water uptake was measured gravimetrically; the compression and compression creep were assessed by dynamic‐mechanical and thermo‐mechanical analysis (DMA and TMA, respectively) techniques. The friction and wear of the hydrogels were determined in a shaft(metal)‐on‐plate(hydrogel) type testing configuration under water lubrication. The hydrogel was transparent and exhibited very high equilibrium water content (>99 wt %). The latter was less affected; however, the hydrogel became slightly more hazy after NB incorporation. The crosslink density of the hydrogels was deduced from swelling and compression tests and compared with the theoretical values. Modification by NB enhanced the ultimate compression strength and reduced the related compression strain. The compression creep response under both loading and deloading strongly depended on the level of the initial load. A very low friction coefficient (～ 0.003) and a relatively high specific wear rate (～ 0.05 mm³/N m) were registered under water lubricated sliding wear using a metallic counterpart with high surface roughness. Scanning electron microscopy combined with energy dispersive spectroscopy delivered additional information on the NB dispersion and surface structure of the hydrogels. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

超临界流体干燥法制备TiO2柱撑膨润土及光催化性能研究

采用溶胶-凝胶法结合超临界流体干燥技术制备了TiO2柱撑膨润土复合光催化剂，通过XRD、BET和FT-IR等分析方法对复合催化剂的物相组成、比表面积和键合状况等物化性能进行了表征，并以Cr(Ⅵ)的光催化还原反应考察其光催化性能。结果表明，用超临界法制备的复合催化剂具有大孔、锐钛矿晶型和沉降性能好等特点，且可实现晶化、干燥一步完成；该复合催化剂的光催化活性接近P25 TiO₂，且明显比空气干燥法制备的高。对于初始浓度为25 mg·L^－1的Cr(Ⅵ)离子，在最佳反应条件2.5 g·L^－1 TiO₂ 柱撑膨润土、溶液初始pH为3.0时，其光催化还原率达到77.6%。     

P(ST-g-ACA)/BT复合降滤失剂的合成与性能

以玉米淀粉、丙烯酰胺、2-丙烯酰胺基-2-甲基丙磺酸、二甲基二烯丙基氯化铵和膨润土为原料,采用单体插层原位聚合法制备了一种复合降滤失剂P(ST-g-ACA)/BT。采用FTIR、XRD、TGA和TEM对其进行表征,对降滤失剂的降滤失性能和流变性能进行了评价,并对其降滤失机理进行了推测。结果表明,该降滤失剂具有"鸡蛋卷"结构和良好的热稳定性。当P(ST-g-ACA)/BT加入量为基浆质量的2.0%时,淡水基浆中滤失量为4 mL(常温中压),含量为10%盐水基浆中(以去离子水的质量为基准,下同)滤失量为22 mL(150℃、3.5 MPa),表明降滤失剂能提高水基钻井液的热稳定性、耐盐性和降滤失性。在含量为10%盐水基浆中,与其他降滤失剂相比,P(ST-g-ACA)/BT降滤失效果明显。     

亚铵法莫浆蒸煮废液的厌氧处理

根据一系列试验结果,分析了亚铵法草浆蒸煮废液厌氧处理的主要特性和机理。间歇式厌氧发酵的试验表明,亚铵废液对厌氧微生物的短期接触临界抑制浓度在7840—11760mg COD/L范围内。长期接触临界浓度大于23520mg COD/L;膨润土能够显著地促进亚铵废液的厌氧发酵。研究结果指出:厌氧—好氧工艺处理亚铵废液具有技术上的可行性和经济上的优越性,发展前景乐观。     

阳离子壳聚糖对纸的增强和助滤作用

增加纸的强度和改善纸料的滤水性以提高生产效率是造纸生产中的重要课题.本文研究了阳离子壳聚糖及其与羧甲基壳聚糖或羧甲基纤维素组成的聚电解质复合物对纸的抗张强度和纸料滤水性的影响,探讨了阳离子壳聚糖与钠基改性膨润土配合提高纸料滤水性的效果.实验结果表明,壳聚糖季铵盐与羧甲基壳聚糖或羧甲基纤维素的复合比例(质量比)分别为0.43和1.2时,聚电解质复合物的浊度最高.聚电解质复合物的加入有效的增加了纸张的抗张强度和滤水性能.阳离子壳聚与羧甲基壳聚糖复合物的增强和助滤效果最好,当其相对于纸浆的加入量为1％时,纸的抗张强度提高了27.69％,纸料的叩解度下降了35.9％.阳离子壳聚糖与膨润土组成的助滤体系可以显著降低纸浆的叩解度,特别是当阳离子化壳聚糖用量较少时,其助滤效果更好.     

两种不同柱撑膨润土对溴离子的去除研究

以钙基膨润土为原料,通过柱撑改性制得两种不同的改性膨润土-铁柱撑膨润土和铝柱撑膨润土。两种膨润土分别应用于溴离子的去除当中。结果表明,两种鹏润如对溴离子的去除效果相差不大。以投加量为0.5 g为例,反应进行20 min时,溴离子的去除率已达到平衡时的90%以上。随着温度由10℃上升到45℃,铝柱撑膨润土和铁柱撑膨润土对溴离子的去除率分别由86.5%和91.7%下降到56.1%和49.6%。随着pH的升高,溴离子的去除率要显著的降低,实验条件下,选取pH 6时,效果最佳。通过吸附动力学和等温线的分析,可知改性膨润土对溴离子的吸附属于自发的放热的过程。     

膨润土作黏结剂制备型煤的研究

以膨润土为黏结剂,采用冷压成型制备出型煤,主要研究了膨润土含量、水分、成型压力和粉煤粒度对型煤抗压强度的影响.结果表明:型煤抗压强度、灰分均与膨润土含量成正比,并得出其线性方程,可根据其工艺需要确定膨润土加入量,计算产品的灰分.水分控制在14％～16％,成型压力为40 kN,膨润土含量为7％时,可制备出平均抗压强度为1420 N/个,灰分为11.7％的型煤.     

膨润土载体缓释肥料的制备工艺优化

以天然廉价的多孔矿物膨润土作为磷酸二氢铵的载体,再加入脲醛树脂胶粘剂经混合、压片固化制得膨润土载体缓释胞。通过单因素实验,考察了膨润土类型、土肥比（膨润土与磷酸二氢铵的质量比,下同）、脲醛树脂用量（以土肥总量计,下同）、碳酸铗用量（以土肥总量计,下同）对缓释肥缓释效果的影响。结果表明,在以钠基膨润土为载体、土肥比为8;2、脲醛树脂用量为20％、碳酸镁用量为9％的条件下,所制得的膨润土载体缓释肥料的缓释效果最好。     

Trivalent chromium removal from tannery effluent using kaolin‐supported bacterial biofilm of Bacillus sp isolated from chromium polluted soil

BACKGROUND: Bacterial strains belonging to the genus Bacillus, isolated from Cr‐ polluted soil (tannery sludge) were employed as consortium for Cr(III) removal from tannery effluents. Kaolin clay, a natural adsorbent, was used as supporting material for bacterial biofilm formation. The use of clay‐supported bacterial biofilm has not previously been employed for the treatment of tannery effluents containing Cr(III) salt. RESULTS: Commercial tannery effluent containing 1000 ppm initial metal ion concentration was treated in stages. The initial Cr(III) concentration of 1000 ppm was brought down to 2 ppm, a permissible level for discharge, after the fourth stage. The bacterial isolates were found to be Bacillus subtilis VITSCCr01 and Bacillus cereus VITSCCr02 by 16s rRNA gene sequencing. Batch assay and confocal laser scanning microscopy results revealed the role of kaolin as a support material in biofilm formation. Best fit was obtained with the Freundlich adsorption isotherm. The mechanism of sorption was confirmed by Fourier transform infrared (FT‐IR) spectroscopy and scanning electron microscopy–energy dispersive X‐ray spectroscopy (SEM‐EDS). CONCLUSION: Cr(III) removal from tannery effluent using low cost adsorbents such as kaolin and bacteria proved to be effective for metal concentrations ?1000 ppm; this is normally not possible using conventional treatment methods. This work has demonstrated feasible sorption of Cr(III), especially during post‐tanning operations. Copyright © 2011 Society of Chemical Industry