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951.
天然水中NO2-和NO3-的毛细管电泳分离测定 总被引:3,自引:0,他引:3
在pH8.2硼酸缓冲液中,用高效毛细管电泳分离硝酸根,硝酸根,并用内标地直接检测了矿泉水,井水中的NO^-2,NO^-3,以CTAB为电渗流改性剂,离子迁移时间相对标准偏差小于1.5%;二甲亚砜夜为内标,样品对内标的峰高比重现性较好。 相似文献
952.
A novel adsorbent named lipoid adsorption material (LAM), with a hydrophobic nucleolus (triolein) and a hydrophilic membrane
structure (polyamide), was synthesized to remove hydrophobic organic chemicals (HOCs) from solution. Triolein, a type of lipoid, was
entrapped by the polyamide membrane through an interfacial polymerization reaction. The method of preparation and the structure
of the LAM were investigated and subsequent experiments were conducted to determine the characteristics of atrazine (a type of
HOC) removal from wastewater using LAM as the adsorbent. The results showed that LAM had a regular structure compared with
the prepolymer, where compact particles were linked with each other and openings were present in the structure of the LAM in which
the fat drops formed from triolein were entrapped. In contrast to the atrazine adsorption behavior of powdered activated carbon (PAC),
LAM showed a persistent adsorption capacity for atrazine when initial concentrations of 0.57, 1.12, 8.31 and 19.01 mg/L were present,
and the equilibrium time was 12 hr. Using an 8 mg/L initial concentration of atrazine as an indicator of HOCs in aqueous solution,
experiments on the adsorption capacity of the LAM showed 69.3% removal within 6–12 hr contact time, which was close to the 75.5%
removal of atrazine by PAC. Results indicated that LAM has two atrazine removal mechanisms, namely the bioaccumulation of atrazine
by the nucleous material and physical adsorption to the LAM membrane. Bioaccumulation was the main removal mechanism. 相似文献
953.
954.
Crop residue open burning is an important emission source of ambient particles in China. This study analyzed the particle emission characteristics of crop residue open burning through combustion experiments with a novel open combustion simulation device using three typical crop straws in north China (corn, wheat, and rice). Particle samples size ranging from 0.006–9.890 µm were collected by an Electrical Low Pressure Impactor plus, a high size-resolution instrument capable of dividing particles into 14 size stages. The size distributions of organic carbon (OC), elemental carbon (EC), water-soluble ions, and elements were analyzed, and source chemical profiles were constructed for PM0.1, PM1, PM2.5, and PM10. The number concentration of particles was concentrated in the Aiken nuclei mode (0.006–0.054 µm), accounting for 75% of the total number, whereas the mass concentration was concentrated in the accumulation mode (0.054–0.949 µm), accounting for 85.43% of the mass loading. OC, EC, Cl?, and K(include total K and water-soluble K) were the major chemical components of the particles, whose mass percentage distributions differed from those of other components. These five main components exhibited a bell-shaped size distribution in the 0.006–9.890 µm range, whereas the other components exhibited a U-shaped distribution. Among the chemical profiles for PM0.1–PM10, OC was the most important component at 10–30%, followed by EC at 2%–8%. The proportions of K+, Cl?, and K varied substantially in different experimental groups, ranging from 0–15%, and K+ and Cl? were significantly correlated (r = 0.878, α = 0.000). 相似文献
955.
土壤重金属对白菜种子发芽与根伸长抑制的生态毒性效应 总被引:96,自引:9,他引:96
测定了水溶液和4种土壤(红壤、草甸棕壤、暗棕壤和栗钙土)条件下,铜、锌、铅、镉单一污染对白菜种子发芽与根伸长的抑制率,以及暗棕壤条件下重金属的复合污染效应.结果表明,同一浓度下,重金属对白菜根伸长抑制率均明显大于对种子发芽抑制率.重金属在土壤中对白菜根伸长抑制效应明显低于其在水体中的抑制效应, 这表明土壤对重金属污染有重要的缓冲作用.铜、锌、铅、镉污染对白菜根伸长抑制率与土壤有机质和土壤氮含量显著负相关;但与土壤pH和土壤钾含量的相关性不显著.铜、锌、铅、镉单一污染对白菜根伸长为刺激作用浓度下,复合污染即产生明显的协同作用,其结果使白菜根伸长的抑制效应阈值明显降低. 相似文献
956.
957.
958.
为了明确天津市区环境受体PM_(2.5)中碳组分的污染特征及来源,本研究分别于2016年2月(冬季)和8月(夏季)在天津市区设置6个采样点位同步采集PM_(2.5)样品,采用热光反射法测定样品中各个碳组分(OC1~OC4、EC1~EC3和OP(裂解碳))的含量,并计算得到OC、EC、CharEC和Soot-EC,以定性识别大气颗粒物中碳组分的来源.结果表明,夏季PM_(2.5)中OC平均浓度为(7.5±3.0)μg·m-3,占PM_(2.5)的11.7%±4.1%;而冬季相比于夏季OC的浓度和占比均有增加,分别为(13.1±7.0)μg·m-3和13.9%±2.8%.夏季和冬季EC浓度分别为(4.0±1.8)μg·m-3、(4.3±2.4)μg·m-3,占PM_(2.5)的6.1%±2.0%和4.6%±1.2%.OC与EC的相关性在夏季(r=0.83,p0.01)和冬季(r=0.96,p0.01)均显著,而冬季CharEC与OC(r=0.94,p0.01)、EC(r=0.98,p0.01)相关性明显高于夏季(OC:r=0.44,p0.01;EC:r=0.45,p0.01).PM_(2.5)中OC/EC平均值在夏季和冬季分别为1.9和3.0,估算得到夏季SOC为(2.6±1.4)μg·m-3,占OC的33.5%±13.6%;冬季为(3.5±2.5)μg·m-3,占OC的26.6%±12.0%.夏季Char-EC/Soot-EC为6.5,高于冬季(4.9),并且空间差异性显著(t检验,p0.05).正定矩阵因子模型(PMF)解析结果表明,天津市区大气PM_(2.5)中碳组分主要有4类来源:燃煤及生物质排放混合源、柴油车、汽油车、道路尘,对夏季PM_(2.5)中碳组分分担率分别为35.4%、16.4%、20.5%、14.4%;对冬季碳组分分担率分别为41.3%、15.5%、18.1%、16.3%.可见,燃煤和机动车是天津市区PM_(2.5)中碳组分的主要来源. 相似文献
959.
新型生物流化床组合工艺处理工业有机废水的工程应用分析 总被引:8,自引:0,他引:8
尝试一种新型结构的生物三相流化床工程化应用于磁电器制品厂的洗涤废水和漂染厂高浓度印染废水的处理 ,处理规模分别为 2 40m3 d和 2 5 0 0m3 d。采用A O2 的流化床组合工艺 ,在总HRT低于 2 4h的操作条件下 ,当洗涤废水进水CODCr负荷为 2 3~ 2 6kg m3·d ,BOD5负荷为 0 72~ 0 95kg m3·d的情况下 ,出水CODCr、BOD5、SS及油分的平均浓度分别为 43 5 0mg L、18 90mg L、2 1 0mg L及 0 86mg L。当印染废水的进水CODCr、BOD5负荷为 3 8~5 8kg m3·d和 1 3~ 1 8kg m3·d时 ,出水CODCr、BOD5浓度分别低于 90mg L和 35mg L。其处理出水均达到了国家一级排放标准。选用的新工艺运行管理方便 ,出水稳定 ,处理费用为 0 6~ 0 8元 t,且基本无污泥产生 ,证明该技术符合清洁生产的环保新概念。实践证明 ,新型生物三相流化床具有体积负荷大 ,抗冲击能力强 ,处理效率高的特点 相似文献
960.
Zhiguang Zhou Yue Ren Jiazhi Chu Nan Li Sen Zhen Hu Zhao Shuang Fan Hui Zhang Pengjun Xu Li Qi Shuting Liang Bin Zhao 《环境科学学报(英文版)》2016,28(6):244-251
To assess the influence of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans(PCDD/Fs) on the environment in the vicinity of municipal solid waste incinerators(MSWIs), we determined the levels of PCDD/Fs in air and soil samples collected around a MSWI, which is the largest in China. The International Toxicity Equivalency Quantity(I-TEQ) concentrations of PCDD/Fs in air samples were from 0.0300 to 1.03 pg I-TEQ/m~3(0.445–13.6 pg/m~3), with an average of 0.237 pg I-TEQ/m~3, while in soil samples they ranged from 0.520 to 3.40 pg I-TEQ/g(2.41–88.7 pg/g) with an average of1.49 pg I-TEQ/g. The concentrations of PCDD/Fs in air and soil samples were comparable to other areas, and Pe CDFs were the dominant contributors, which was different from stack gas homologue patterns. Multivariate statistical analysis showed that PCDD/Fs emission from the MSWI did not directly affect the profiles of PCDD/Fs in air and soils, so that vehicles and unidentified emission sources should be considered. The daily inhalation levels of PCDD/Fs for children(0.0110 to 0.392 pg I-TEQ/(kg·day) and adults(0.00600 to 0.221 pg I-TEQ/(kg·day) near the MSWI were lower than the tolerable daily intake of 1.00 to 4.00 pg WHO-TEQ/(kg·day), but in winter the values were higher than in summer. These results can be used as basic data for assessing the risk of PCDD/Fs exposure in residents living around this MSWI, and more monitoring programs and studies should be carried out around MSWIs. 相似文献