催化裂化钠碱脱硫液中钙镁离子的去除

研究了化学沉淀法和氨基膦酸型螯合树脂吸附法对催化裂化钠碱脱硫液中Ca~(2+)和Mg~(2+)的去除效果。实验结果表明:NaOH沉淀法可有效去除钠碱脱硫液中的Mg~(2+),当溶液pH为12、反应时间为15 min时,Mg~(2+)去除率达91.6%;NaOH-Na_2CO_3联合沉淀法无法去除钠碱脱硫液中的Ca~(2+);经过NaOH溶液有效除Mg~(2+)后的脱硫液再采用氨基膦酸型螯合树脂吸附柱去除其中的Ca~(2+)和Mg~(2+),可使出水硬度小于2 mg/L。提高进水pH、降低进水流量、降低进水硬度均可提高单位体积树脂的处理水量。     

改性壳聚糖处理微生物浸矿废水

为解决采矿行业微生物浸矿酸性废水中和处理沉渣多、固液分离困难的问题,采用柠檬酸钠和环氧氯丙烷改性处理的壳聚糖在pH=2.2条件下吸附模拟废水中的Cu²⁺和Fe³⁺,用正交实验优化了壳聚糖改性工艺条件。实验结果表明,最适宜的工艺条件为：处理100 mL壳聚糖质量分数为2%的壳聚糖-冰醋酸溶液,柠檬酸钠缓冲溶液加入量200 mL,环氧氯丙烷加入量300 mL,反应时间6 h。改性壳聚糖对Fe³⁺的最大吸附容量为6.703 7 mg/g,对Cu²⁺的最大吸附容量为4.378 7 mg/g,Fe³⁺和Cu²⁺在改性壳聚糖上的吸附是单分子层形式。     

亚硝酸盐氮测定中的稳定性试验

对亚硝酸盐氮测定的清洁水样及1．00mg／L亚硝酸盐氮标准使用溶液分别进行了稳定性试验,试验表明,清洁水样置冰箱内至少可保存30d;1．00mg／L亚硝酸盐氮标准溶液可保存180d,大大延长了国标方法中规定的24h的保存期,既提高了工作效率,又节约了试剂,在实际工作中具有一定的可行性及推广性。     

Removal of heavy metals from aqueous solution by sawdust adsorption

The adsorption of lead, cadmium and nicel from aqueous solution by sawdust of walnut was investigated. The effect of contact time, initial metal ion concentration and temperature on metal ions removal has been studied. The equilibrium time was found to be of the order of 60 min. Kinetics fit pseudo first-order, second-order and intraparticle diffusion models, hence adsorption rate constants were calculated. The adsorption data of metal ions at temperatures of 25, 45 and 60~C have been described by the Freundlich and Langmuir isotherm models. The thermodynamic parameters such as energy, entropy and enthalpy changes for the adsorption of heavy metal ions have also been computed and discussed. Ion exchange is probably one of the major adsorption mechanisms for binding divalent metal ions to the walnut sawdust. The selectivity order of the adsorbent is Pb（I1）~Cd（II）〉Ni（I1）. From these results, it can be concluded that the sawdust of walnut could be a good adsorbent for the metal ions from aqueous solutions.     

Copper biosorption on immobilized seaweed biomass： Column breakthrough characteristics

The biosorption of copper by the brown seaweed Sargassum baccularia,immobilized onto polyvinyl alcohol(PVA)gel beads, was investigated with fixed-bed experiments.Laboratory-scale column tests were performed to determine breakthrough curves with varying flow rates and feed concentrations.A theoretical fixed-bed model,known as the Bohart-Adams equation,was evaluated in simulating the experimental breakthrough curves.The Bohart-Adams model qualitatively predicted the breakthrough trends.PVA- immobilized seaweed biomass beads were amenable to efficient regeneration with aqueous solution containing the chelating agent ethylenediaminetetraacetic acid(EDTA).The biosorbent retained most of its original uptake capacity over three cycles of use.The excellent reusability of the biosorbent could lead to the development of a viable metal remediation technology.     

Effect of sorbed and desorbed Zn(Ⅱ) on the growth of a green alga (Chlorella pyrenoidosa)

Toxic effect of Zn(Ⅱ) on a green alga (Chlorella pyrenoidasa) in the presence of sepiolite and kaolinite was investigated.The Zn-free clays were found to have a negative impact on the growth of C.pyrenoidosa in comparison with control samples (without adding any clay or Zn(Ⅱ)).When Zn(Ⅱ) was added,the algae in the presence of clays could be better survived than the control samples,which was actually caused by a decrease in Zn(Ⅱ) concentration in the solution owing to the adsorption of Zn(Ⅱ) on the clays.When the solution system was diluted,the growth of algae could be further inhibited as compared to that in a system which had the same initial Zn(Ⅱ) concentration as in the diluted system.This in fact resulted from desorption of Zn(Ⅱ) from the zinc-contaminated clays,although the effect varied according to the different desorption capabilities of sepiolite and kaolinite.Therefore the adsorption and desorption processes of Zn(Ⅱ) played an important part in its toxicity,and adsorption and desorption of pollutants on soils/sediments should be well considered in natural eco-environmental systems before their risk of toxicity to aquatic organisms was assessed objectively.     

Adsorption removal of phosphate from aqueous solution by active red mud

Red mud is the waste of alumina industry and has high TiO_2 and Fe_2O_3 content which are active components for the adsorption of anion pollutants.In this study,the uptake of phosphate by red mud activated by heat treatment and acid-heat treatment was investigated. The factors influencing the adsorption were also investigated.The result showed that the red mud sample treated using acid-heat method at 80℃with 0.25 mol/L HC1 for 2 h achieved the highest phosphate removal.For the heat-activated red mud,the sample heated at 700℃for 2 h preformed better than the other heat treatment.Phosphate removal by the activated red mud was significantly pH dependent,and pH 7 was the optimal pH for phosphate removal.The adsorption fits Langmuir isotherm model well and the maximum adsorption capacities of the acid-heat activated red mud and the heat activated samples were 202.9 mgP/g and 155.2 mgP/g,respectively.     

采用零排放新工艺处理蚀刻废液

广州市某化工厂开发出一套对线路板蚀刻废液进行大规模集中资源化处理的零排放处理新工艺,该工艺通过在固相条件下生成氧化铜并用重力分选的方法将其分离出来,克服了原有工艺的缺陷,使废液中所有的成分能够在较低的处理成本下全部分离回收,无三废排出,达到了清洁生产的要求.对其工艺条件进行深入研究,通过正交试验优化了工艺条件.     

X-42钢在碳酸钠-碳酸氢钠溶液中慢拉伸时电化学噪音信号的小波分析

本文应用小波分析理论研究了X42管线钢在0.5 mol/l Na2CO3 1 mol/l NaHCO3溶液中,在-950mVSCE、-1100mVSCE阴极极化条件下,慢应变速率实验过程中的极化电流信号.结果表明,极化电流信号的低频部分代表着其发展趋势.在阴极极化时,由于阴极析氢造成的体系pH值升高,因而电流信号有逐渐增大的趋势.而且,在对SSRT过程中阴极极化电流信号进行分析时,并未发现第二类间断点.因此,对于工业腐蚀监控,是否可用出现第二类间断点来预测X-42钢在土壤中的应力腐蚀失效,还有待于进一步的研究与探讨.     

溶液特性及共存物对纳滤膜去除水中全氟辛酸的影响

利用聚酰胺复合纳滤(NF)膜去除水中的持久性有机污染物—全氟辛酸(PFOA),分别研究了PFOA浓度、溶液离子强度、pH值、典型大分子有机物—牛血清蛋白(BSA)以及BSA与Na+共存对PFOA截留率的影响.结果表明,在0.8MPa下过滤24h,随着PFOA浓度增大,PFOA截留率提高;溶液离子强度、pH值越高,PFO...