1992～2004年西安市环境经济发展协调度分析

环境与经济相协调是实现可持续发展的基本要求。文章在总结近10年来国内相关研究的基础上,提出了较为综合的环境经济复合系统协调度概念及计算方法。在此基础上,利用西安市的统计数据,测算了1992～2004年西安市环境经济发展的协调度。结果表明,西安市环境经济协调发展的整体水平较低,城市环境管理工作的绩效很不稳定,需要得到加强和改进。     

黄钠铁矾渣制备透明氧化铁黄的研究

研究了以黄钠铁矾渣为原料,采用滴加法制备透明铁黄的工艺条件,讨论了亚铁浓度、温度、通气量、搅拌速度及添加剂用量等因素对铁黄制备的影响.用XRD和TEM对产品进行表征.结果表明,铁黄粒子呈针状;长轴为95～125 nm,短轴为18～25 nm;无团聚现象,单分散性好.     

铁屑去除酸法地浸采铀地下水中硝酸盐的试验研究

在酸法地浸采铀过程中,硝酸及硝酸盐的广泛使用使硝酸盐在地下不断累积并扩散到地下水中,这给矿区地下水造成了一定程度的污染.本试验以铁屑为还原剂,对该地下水中NO3--N的去除进行了批试验和动态试验研究.试验结果表明,铁屑可有效去除地下水中的NO3--N,其去除率随pH值的降低而逐渐升高;溶液中共存的Ca2 、Mg2 对NO3--N的去除影响不大,而SO42-、HCO3-的存在可明显降低NO3--N去除率;铁屑最佳投加量为120 g/L,铁炭最佳体积比为1∶1;二级柱可以明显提高柱子的稳定运行时间,在55 h内NO3--N去除率可保持在93%以上,去除效果较好.     

铁阳极电凝聚处理活性黑KN-B染料废水

对铁阳极电凝聚处理活性黑KN-B染料废水过程进行了实验研究.考察了电流密度、染料溶液初始pH值、电介质浓度及种类、温度、染料浓度等因素对脱色效率的影响.结果表明,在一定实验条件下,活性黑KN-B模拟废水的脱色效率达93%;电流强度、染料浓度、电解液初始pH值及电解质的种类对染料溶液脱色效率影响显著,电解液温度、电解质的浓度对脱色效率的影响不明显;以铁为阳极的原位电凝聚处理活性黑KN-B模拟废水混凝过程中主要作用机理以吸附电性中和为主;电凝聚过程中活性黑KN-B在阴极上发生了还原反应.     

气相色谱法测定空气和废气中8种烃类化合物

建立了针筒采样、大口径毛细管柱分离、气相色谱-氢火焰离子化检测器测定空气和废气中甲烷、乙烷、乙烯、乙炔、丙烷、异丁烷、正丁烷和正戊烷等8种烃类化合物的方法.优化了试验条件,方法线性良好,甲烷、乙烯、乙炔、乙烷、丙烷、异丁烷、正丁烷和正戊烷的检出限分别为0.09 mg/m3、0.20 mg/m3、0.18 mg/m3、0.29 mg/m3、0.28 mg/m3、0.37 mg/m3、0.16 mg/m3和0.56 mg/m3,RSD＜8.0%,加标回收率为80.5%～104%.     

污水污泥间壁热干燥实验研究

研究了污泥间壁热干燥的工艺过程,分析了其工艺参数、冷凝水水质和产生的污染气体,探讨了有机物水解机理.结果表明,污泥含水率与停留时间呈负指数函数相关.收集到的干燥冷凝水属高浓度有机废水,其总有机碳（TOC）、挥发性有机酸（VFA）和氨氮（NH₃-N）浓度均很高,pH值保持在9～9.5.干燥冷凝水中挥发性有机酸和氨氮来源于2部分：低温110 ～130℃时,主要发生蛋白质的水解,生成有机酸和氨氮;高温140～150℃时,主要发生脂肪类的水解,生成有机酸.干燥温度低于150 ℃时,污泥间壁热干燥过程无污染气体产生.     

零价铁-反硝化菌在地下水硝酸盐污染修复中的应用

综述了应用零价铁-反硝化菌复合体系去除地下水中硝酸盐氮污染的研究进展.脱氮技术主要包括物理化学法、化学还原法和生物反硝化法,但单独使用任何一种方法都无法得到令人满意的处理效果.以零价铁在水中厌氧腐蚀所释放的氯气供给微生物进行反硝化,可以同时解决这两种技术单独使用时所存在的弊端.在此复合体系中,主要反应包括产氨、析氢和反硝化,降低脱氮产物中的氨氮比例就要减少产氨反应的发生几率.此外,使用纳米铁代替零价铁和反硝化细菌复合,可以大大提高脱氮反应速率.然而,该技术的研究在国内外尚处于起步阶段,在反应机理、产物控制、条件优化等方面都存在不足,还需要深入研究.     

Effects of long-term amendment of organic manure and nitrogen fertilizer on nitrous oxide emission in a sandy loam soil

To understand the effects of long-term amendment of organic manure and N fertilizer on N2O emission in the North China Plain, a laboratory incubation at different temperatures and soil moistures were carried out using soils treated with organic manure （OM）, half organic manure plus half fertilizer N （HOM）, fertilizer NPK （NPK）, fertilizer NP （NP）, fertilizer NK （NK）, fertilizer PK （NK） and control （CK） since 1989. Cumulative N2O emission in OM soil during the 17 d incubation period was slightly higher than in NPK soil under optimum nitrification conditions （25℃ and 60% water-filled pore space, WFPS）, but more than twice under the optimum denitrification conditions （35℃ and 90% WFPS）. N2O produced by denitrification was 2.1-2.3 times greater than that by nitrification in OM and HOM soils, but only 1.5 times greater in NPK and NP soils. These results implied that the long-term amendment of organic manure could significantly increase the N2O emission via denitrification in OM soil as compared to NPK soil. This is quite different from field measurement between OM soil and NPK soil. Substantial inhibition of the formation of anaerobic environment for denitrification in field might result in no marked difference in N2O emission between OM and NPK soils. This is due in part to more rapid oxygen diffusion in coarse textured soils than consumption by aerobic microbes until WFPS was 75% and to low easily decomposed organic C of organic manure. This finding suggested that addition of organic manure in the tested sandy loam might be a good management option since it seldom caused a burst of N2O emission but sequestered atmospheric C and maintained efficiently applied N in soil.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.     

Adsorption thermodynamics and kinetic investigation of aromatic amphoteric compounds onto different polymeric adsorbents

The adsorption behavior of p-aminobenzoic acid and o-aminobenzoic acid onto the different polymeric adsorbents was systematically investigated as a function of the solution concentration and temperature.Experimental results indicated that the equilibrium adsorption data of the four polymeric adsorbents fitted well in the Freundlich isotherm.The adsorption capacity of multi-functional polymeric adsorbent NJ-99 was the highest,which might be attributed to the strong hydrogen-bonding interaction between the amino groups on the resin and the carboxyl group of aminobenzoic acid.The adsorption capacity of o-aminobenzoic acid onto any adsorbent was higher than p-aminobenzoic acid.Thermodynamic studies suggested the exothermic,spontaneous physical adsorption process.Adsorption kinetics results showed that the adsorption followed the pseudo-second-order kinetics model and the intraparticle mass transfer process was the rate-controlling step.