炼化废水絮凝剂筛选实验

中国石油大连石化公司的生产废水不仅具有炼化废水的复杂性,而且其中含有大量的氯离子,给絮凝药剂的筛选带来一定的困难。通过对715、728两种絮凝药剂的现场应用实验,找出了不同水质情况下的最佳投药量。实验结果表明,当污水中含油量大于100mg/L时,715药剂加入量控制在150～180mg/L,728的加入量为4mg/L,此时油、SS、COD、浊度的去除率分别为92%、41%、41%和82%。当污水含油量在30mg/L以下时,715药剂加入量为90～120mg/L,728加入量为2.7～3.3mg/L,此时油、SS、COD、浊度的去除率分别为74%、71%、38%和89%。经实验筛选出的这两种药剂可以利用现有的加药系统设备加入污水,加药处理后能提高出水的水质。     

COD_(Cr)测定中排除氯离子干扰的进一步探讨

废水中化学需氧量的测定采用重铬酸钾法［１］,大多数情况下都存在Ｃｌ－干扰,其排除方法用ＨｇＳＯ４掩蔽,通过实验探讨不用剧毒药品ＨｇＳＯ４掩蔽Ｃｌ－的干扰,而用ＣＯＤＣｒ总量减去Ｃｌ－的量。实验结果表明：当测定化学需氧量较低而Ｃｌ－含量高的水样时,即使采用掩蔽Ｃｌ－也会产生较大的误差,而用测定值减去０．２２６［Ｃｌ－］之值更接近真值。     

筛板塔烟气湿法脱硫工艺的研究

以石灰石浆液作为脱硫剂,在筛板塔反应器中进行湿法脱硫实验,主要考察浆液p H、脱硫添加剂、粉尘对筛板塔湿法脱硫效果的影响。实验表明:筛板塔能适应高浓度的烟气脱硫,在一定范围内,随着吸收塔浆液p H的升高,脱硫率也呈上升趋势;筛板塔脱硫效率随入口粉尘浓度的升高而降低,且粉尘加入量越多,脱硫效率下降越显著;而有机添加剂己二酸的加入可以提高脱硫系统脱硫率和吸收剂的利用率,从而降低脱硫系统运行成本。     

天然水和污水中的硒的催化极谱法测定

在 NH_4Cl～NH_4OH 缓冲溶液中用 ED-TA 掩蔽金属离子,利用 So_2—So_2—KIO_3的催化波测定天然水中痕迹量硒。试样必须用硫酸～高氯酸低温消解,如遇污水要反复消解至无色为止。缓冲液用优级纯浓氢氧化铵和固体氯化铵配制不必加水稀释。方法灵敏度为1×15~(-5)微克/毫升。只需10毫升原样即可测至0.01PPb。变动系数最高是25%.天然水中硒硒含量在0.0X～0.XPPb.用化学法测定手续繁琐。近年来用极谱催化法测定硒时有报道,在此基础上仅就硒分析中的 pH 条件,试剂加入量,共存离子的影响,以及在污水中的应用作了探讨,结果如下:     

不经蒸馏直接测定天然水中氰化物

本文采用EDTA掩蔽天然水中常见的干扰组份,可不经蒸馏直接测定天然水中的氰化物。在加入5％EDTA5ml进行测定时,方法的摩尔系数为6.0×10~4l/mol·cm。对含氰为4.0～6.0ppb的天然水的测定,回收率为92.6～104.8％,相对标准偏差为4.5～11.3％。     

利用含油污泥生产油煤水浆的实验研究

利用降粘技术,将高粘度含油污泥降粘为流动性良好的浆体。实验表明:合适的降粘剂加入量为1.0%。利用降粘后的含油污泥制备出具有良好浆体特性的油煤水浆。当降粘后含油污泥加入量分别为油煤水浆总量的20%和30%时,制备的油煤水浆粘度均小于300mPa.s,浆体粘度随温度升高不断降低,具有良好的剪切变稀特性。制备的油煤水浆不需加入稳定剂,一个月内未发生硬沉淀或分层现象,具有较好的稳定性。     

废钻井液脱稳与ξ电位关系的研究

为了寻求钻井液脱稳剂H2SO4的最佳用量,采用JS94B型微电泳仪对钻井液体系的ξ电位进行了研究。实验中测定了钻井液在不同稀释倍数下ξ电位的变化情况,研究了脱稳剂H2SO4加量与钻井液临界ξ电位的关系,从而得出H2SO4加入量以045mL/100g废钻井液为宜,其临界ξ电位为-752997mV。     

硫酸亚铁法与硫化钠法处理络合铜废水的对比研究

通过硫酸亚铁（FeSO4）法和硫化钠（Na2S）法处理络合铜废水的对比实验研究，探讨了FeSO4和Na2S破络机理、两种药剂的授加量、pH值、絮凝剂（PAM）的加入量对铜去除率的影响，分析两种处理方法的优缺点，以期为线路板厂络合铜废水处理提供参考。     

冷轧废乳化液混凝破乳试验研究

试验针对某冷轧带钢公司的废乳化液,研究了聚合硫酸铁(PFS)、聚合氯化铝(PAC)、硫酸铁[Fe_2(SO_4)_3·7H_2O]、硫酸亚铁(FeSO_4·7H_2O)对废乳化液的混凝-上浮影响。实验结果表明,4种混凝剂对破乳效果均较好,综合考虑絮体状态、处理效果及成本,确定硫酸亚铁为本试验的最佳药剂。试验温度为实验季节水温,温度为20℃左右。最佳试验条件为:硫酸亚铁投加量为4 g/L,PAM投加量为0.04 g/L,pH=8,此时COD去除率为95.2%,油去除率为96.7%。     

RD复合净水剂对阳离子染料RL的吸附脱色

考察了RD复合净水剂吸附处理阳离子艳兰染料RL废液的实验条件,探讨了RD吸附脱色的实质。结果表明,加入0.3gRD到浓度为200mg/L的染液中,在25℃、pH=7.0条件下,吸附时间为10m in时,废液的脱色率达到80%,RD单位质量吸附量为10.7mg/g;当50mg/L的染料废液中,RD的投加量为0.2g时,脱色率达到了96%以上,RD单位质量吸附量为8.12mg/g;pH值和温度对吸附脱色效果影响不显著,而且RL废液的浓度增大,RD单位质量吸附量增大,但是脱色率有所下降。RD对染料的吸附符合Langmu ir吸附模型。     

消除氯离子对CODcr快速仪法干扰的实验

氯离子浓度高于５００ｍｇ／Ｌ时,对ＣＯＤｃｒ的测定呈混浊干扰,通过加入ＨｇＳＯ４络合氯离子,可消除氯离子含量达２０００ｍｇ／Ｌ的干扰,过量的ＨｇＳＯ４对ＣＯＤｃｒ结果无影响。     

Sorption of iron-cyanide complexes on goethite in the presence of sulfate and desorption with phosphate and chloride

Soils are contaminated with potentially toxic iron-cyanide complexes by some industrial activities. The influence of sulfate on the sorption of the iron-cyanide complexes ferricyanide, [Fe(CN)6]3-, and ferrocyanide, [Fe(CN)6]4-, on goethite was investigated in batch experiments. The experiments were conducted as influenced by pH and varying sulfate/iron-cyanide complex concentration ratios. Furthermore, the desorption of iron-cyanide complexes sorbed on goethite was studied using phosphate and chloride solutions as influenced by pH and anion concentration. Over the whole pH range (pH 3.5 to 8), ferricyanide and sulfate showed similar affinities for the goethite surface. The extent of ferricyanide sorption strongly depended on sulfate concentrations and vice versa. In contrast, ferrocyanide sorption was only decreased (approximately 12%) by sulfate additions at pH 3.5. Ferricyanide was completely desorbed by 1 M chloride, ferrocyanide not at all. Unbuffered phosphate solutions (pH 8.3) desorbed both iron-cyanide complexes completely. Even in 70-fold excess, pH-adjusted phosphate solutions could not desorb ferrocyanide completely at pH 3.5. For ferricyanide we propose a sorption mechanism that is similar to the sulfate sorption mechanism, including outer-sphere and weak inner-sphere surface complexes on goethite. Ferrocyanide appears to form inner-sphere surface complexes. Additionally, we assume that ferrocyanide precipitates probably as a Berlin Blue-like phase at pH 3.5. Hence, ferrocyanide should be less mobile in the soil environment than ferricyanide or sulfate.     

高氯低COD废水中COD的测定

以某污水厂的高氯低COD生化出水为研究对象,探讨了硫酸汞加入量、K2Cr2O7溶液浓度、反应酸度、取水样量等参数对COD测定的影响,探讨消除该厂Cl-干扰最简单有效方法,结果表明:控制硫酸汞与氯离子比为15∶1(质量比)、K2Cr2O7浓度为0.18 mol/L、水样稀释0.75倍、Ag2SO4-H2SO4加入量为28mL,皆可有效减少氯离子的干扰。该方法相对氯气校正法,操作简单、准确可靠。     

Temperature and wetland plant species effects on wastewater treatment and root zone oxidation

Constructed wetlands are widely used for wastewater treatment, but there is little information on processes affecting their performance in cold climates, effects of plants on seasonal performance, or plant selection for cold regions. We evaluated the effects of three plant species on seasonal removal of dissolved organic matter (OM) (measured by chemical oxygen demand and dissolved organic carbon) and root zone oxidation status (measured by redox potential [Eh] and sulfate [SO4(2-)]) in subsurface-flow wetland (SSW) microcosms. A series of 20-d incubations of simulated wastewater was conducted during a 28-mo greenhouse study at temperatures from 4 to 24 degrees C. Presence and species of plants strongly affected seasonal differences in OM removal and root zone oxidation. All plants enhanced OM removal compared with unplanted controls, but plant effects and differences among species were much greater at 4 degrees C, during dormancy, than at 24 degrees C, during the growing season. Low temperatures were associated with decreased OM removal in unplanted controls and broadleaf cattail (Typha latifolia L.) microcosms and with increased removal in beaked sedge (Carex rostrata Stokes) and hardstem bulrush [Schoenoplectus acutus (Muhl. ex Bigelow) A. & D. L?ve var. acutus] microcosms. Differences in OM removal corresponded to species' apparent abilities to increase root zone oxygen supply. Sedge and bulrush significantly raised Eh values and SO4(2-) concentrations, particularly at 4 degrees C. These results add to evidence that SSWs can be effective in cold climates and suggest that plant species selection may be especially important to optimizing SSW performance in cold climates.     

Screening of factors influencing Cu(II) extraction by soybean oil-based organic solvents using fractional factorial design

This study aimed to identify the significant factors that give large effects on the efficiency of Cu(II) extraction from aqueous solutions by soybean oil-based organic solvents using fractional factorial design. Six factors (mixing time (t), di-2-ethylhexylphosphoric acid concentration ([D2EHPA]), organic to aqueous phase ratio (O:A), sodium sulfate concentration ([Na(2)SO(4)]), equilibrium pH (pH(eq)) and tributylphosphate concentration ([TBP])) affecting the percentage extraction (%E) of Cu(II) were investigated. A 2(6-1) fractional factorial design was applied and the results were analyzed statistically. The results show that only [D2EHPA], pH(eq) and their second-order interaction ([D2EHPA] × pH(eq)) influenced the %E significantly. Regression models for %E were developed and the adequacy of the reduced model was examined. The results of this study indicate that fractional factorial design is a useful tool for screening a large number of variables and reducing the number of experiments.     

Residual and contact herbicide transport through field lysimeters via preferential flow

Usage of glyphosate [N-(phosphonomethyl)-glycine] and glufosinate [2-amino-4-(hydroxy-methylphosphinyl)butanoic acid] may reduce the environmental impact of agriculture because they are more strongly sorbed to soil and may be less toxic than many of the residual herbicides they replace. Preferential flow complicates the picture, because due to this process, even strongly sorbed chemicals can move quickly to ground water. Therefore, four monolith lysimeters (8.1 m(2) by 2.4 m deep) were used to investigate leaching of contact and residual herbicides under a worst-case scenario. Glufosinate, atrazine (6-chloro-N(2)-ethyl-N(4)-isopropyl-1,3,5-triazine-2,4-diamine), alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl) acetamide], and linuron (3-3,4-dichlorophenyl-1-methoxy-1-methylurea) were applied in 1999 before corn (Zea mays L.) planting and glyphosate, alachlor, and metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one] were applied in 2000 before soybean [Glycine max (L.) Merr.] planting. A high-intensity rainfall was applied shortly after herbicide application both years. Most alachlor, metribuzin, atrazine, and linuron losses occurred within 1.1 d of rainfall initiation and the peak concentration of the herbicides coincided (within 0.1 d of rainfall initiation in 2000). More of the applied metribuzin leached compared with alachlor during the first 1.1 d after rainfall initiation (2.2% vs. 0.035%, P < 0.05). In 1999, 10 of 24 discrete samples contained atrazine above the maximum contaminant level (atrazine maximum contaminant level [MCL] = 3 mug L(-1)) while only one discrete sample contained glufosinate (19 mug L(-1), estimated MCL = 150 mug L(-1)). The results indicate that because of preferential flow, the breakthrough time of herbicides was independent of their sorptive properties but the transport amount was dependent on the herbicide properties. Even with preferential flow, glyphosate and glufosinate were not transported to 2.4 m at concentrations approaching environmental concern.     

复合絮凝剂Al2(SO4)3+PAM处理生活污水中CODCr和浊度的实验研究

研究絮凝剂硫酸铝Al2(SO4)3与助凝剂聚丙烯酰胺(PAM)联合处理生活污水的效果。研究表明:Al2(SO4)3与PAM联用比单独用Al2(SO4)3处理生活污水效果更好;Al2(SO4)3 PAM对生活污水CODCr和浊度具有良好的去除能力;当投加1:1的50mg/L的Al2(SO4)3 0.5mg/L的PAM,调节水体pH=7时,处理效果最理想,CODCr去除率可达95.8%,浊度去除率可达97.5%。为复合絮凝剂Al2(SO4)3 PAM处理生活污水的应用提供了有价值的参考依据。     

The use of ion exchange membranes for isotope analyses on soil water sulfate: laboratory experiments

To investigate the potential use of anion exchange membranes (plant root simulator [PRS] probes) for isotope investigations of the soil sulfur cycle, laboratory experiments were performed to examine the sulfate exchange characteristics and to determine the extent of sulfur and oxygen isotope fractionation during sulfate sorption and desorption on the probes in aqueous solutions and simulated soil solutions. The sulfate-exchange tests in aqueous solutions under varying experimental conditions indicated that the amount of sulfate exchanged onto PRS probes increased with increasing reaction time, initial sulfate concentration, and the number of probes used (= surface area), whereas the percentage of removal of available sulfate was constant irrespective of the initial sulfate concentration. The competition of nitrate and chloride in the solution lowered the amount of exchanged sulfate. The exchange experiments in a simulated soil under water-saturated and water-unsaturated conditions showed that a considerable proportion of the soil sulfate was exchanged by the PRS probes after about 10 d. There was no evidence for significant sulfur and oxygen isotope fractionation between soil sulfate and sulfate recovered from the PRS probes. Therefore, we recommend the use of PRS probes as an efficient and easy way to collect soil water sulfate for determination of its isotope composition.