浊点萃取-FAAS法测定化妆品中六价铬

提出了浊点萃取-火焰原子吸收光谱法测定化妆品中痕量六价铬的方法。考察了溶液pH、APDC用量、Triton X-114用量、平衡温度及时间等条件对浊点萃取率的影响,在优化条件下,对化妆品进行测定。该方法测定铬的检出限为0.026 mg/L,相对标准偏差为1.52%。结果表明：市售多数化妆品中的铬含量超过国家标准,须引起质量监督部门的注意。     

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...     

Reduction of Cr(VI) to Cr(III) and removal of total chromium from wastewater using scrap iron in the form of zerovalent iron(ZVI): Batch and column studies

This work experimentally investigates Cr(VI) reduction to Cr(III) using waste scrap iron in the form of zerovalent iron (ZVI) collected from the mechanical workshop of the Institute, both in batch and continuous operation. The reduction of Cr(VI) to Cr(III) was found to be complete (～100%) depending on the experimental conditions. Lower pH values favour Cr(VI) reduction. Two concurrent reactions take place, that is reduction of Cr(VI) by Fe⁰ (ZVI) and by Fe²⁺ generated due to H⁺ corrosion of iron. Maximum around 22%, 11% and 2% Cr(III) remained dissolved in solution while the experiments were carried out at initial pH of 2, 4.67 and 7. Higher ZVI loading increases Cr(VI) reduction rate, however, consumption of iron is noted to be higher. The results indicate that the bed is exhausted rapidly at higher pH, initial Cr(VI) concentration and flow rate. This is attributable to predominance passivation of ZVI surface forming Cr(III)–Fe(III)‐oxide layer. SEM analysis of ZVI before and after the experiments confirms formation of passive oxide on iron surface is responsible for deterioration of Cr(VI) reduction efficiency due to its blanketing effect.     

铬酸酐生产中硫酸氢钠回收利用研究与应用

研究了废液硫酸氢钠组分及回收利用中需解决的问题，并阐述了硫酸氢钠的预处理过程，中和条件，反应温度及熟化时间，同时提出了生产中的注意要点。     

Electrochemical study of the chromium electrode behaviour in borate buffer solution

The electrochemical behaviour of the chromium electrode in borate buffer solution (pH 9.3) was studied by cyclic voltammetry and electrochemical impedance spectroscopy. Chromium passivity was observed over a broad potential region, from –1.0 to 0.5 V vs SCE. The passivation process took place in two steps: formation of a chromium oxide monolayer and transition of chromium to a higher valence state. The anodic film exhibited the properties of a p-type semiconductor. Transpassive dissolution of chromium occurred at 0.5 V vs SCE, with two reaction intermediates present, Cr_Cr ^III and Cr_ad ⁴⁺.     

冶炼铅锌废渣配料对湿法回转窑生产的影响

研究了冶炼铅锌废渣配料对湿法水泥生产的影响。研究结果表明，冶炼铅锌废渣配料，在相同水分情况下，可使生料浆流动度增加2－3mm，生料易烧性较好；冶炼铅锌废渣配料不仅有利于A矿的形成与发育，促进A矿的快速生长，增加A矿含量，提高熟料烧成质量，而且有利于延长烧成带镁铬砖的寿命。     

内循环式泡沫浮选塔处理含铬废水

采用自制的内循环泡沫浮选塔处理含铬废水,考察pH值、Fe(NO3)3浓度、十二烷基硫酸钠(SDS)浓度、气体流量、分离时间等因素对分离效率的影响,并与常规泡沫塔比较. 结果表明,在12~35 min内,内循环式浮选塔分离效率更高,35 min时塔内铬离子浓度为0.6 mg/L,常规泡沫塔内铬离子浓度为10 mg/L. 内循环浮选塔最佳分离工艺条件为,对初始铬浓度为20 mg/L的废水,在pH 5.5、SDS 100 mg/L、Fe(NO3)3 60 mg/L、气体流量800 mL/min条件下处理效果最好,泡沫夹带率约为10%,Cr(III)脱除率可达97%以上.     

乙烯聚合Phillips型铬系催化剂研究进展

Phillips型铬系催化剂由于制备工艺简单,聚合过程不使用任何助催化剂,广泛应用于乙烯聚合,对世界聚烯烃工业的发展具有重要的推动作用。主要从Phillips型铬系催化剂的发展历程、催化剂制备与结构和聚合产品特性方面进行综述,并指出今后我国铬系催化剂的研发方向。     

中空纤维膜电泳法富集水中的Cr(Ⅵ)

建立了一种中空纤维膜电泳快速富集水中CrO42--(Cr(Ⅵ))的方法.施加电压、搅拌速度和富集时间是影响富集倍数的主要参数,并对这3个条件进行了考察.确定最佳富集条件为:施加电压为20 V,搅拌速度为600 r/min,富集时间为15min.结果表明,应用本方法富集水中的Cr(Ⅵ)并进行测定,富集速度快,富集倍数高达约30倍,能显著提高水中Cr(Ⅵ)的富集速度和检测灵敏度.     

提高硬铬镀层耐蚀性的双层镀铬工艺

以某型发动机的水泵轴为基体,在同一镀液和镀槽中电沉积制备乳白/光亮双层铬镀层。工艺流程为:前处理─装挂─入槽─镀乳白耐蚀铬─镀光亮耐磨铬─出槽─清洗─除氢─抛光─检验。镀液组成为:CrO3200~250g/L,H2SO42.2~2.6g/L,Cr3+离子2.0~3.5g/L。先在60~65℃、15~25A/dm2下施镀30min得到乳白铬镀层,随后在55~60℃、40~50A/dm2下施镀90min,即得乳白/光亮双层铬镀层。双层铬镀层的孔隙率比单层光亮铬镀层小,二者显微硬度相近,耐磨性优越。实际生产应用表明,双层铬镀层的耐蚀性优于单层光亮铬镀层。