海带吸附铜、镍离子的研究

[目的]研究海带吸附铜、镍离子过程中的影响因素。[方法]在100ml铜/镍离子溶液中加入0.2g海带粉,所有试验的振荡速度均设为120r/min,用原子分光光度计测定过滤后溶液中的铜、镍离子浓度。[结果]海带吸附铜、镍离子的最佳pH值为4.0。海带对镍离子的吸附平衡时间为60min,对铜离子的吸附平衡时间为90min,吸附等温线均符合Freundlich模型。在pH值为3.0时,海带对铜离子的吸附效率达80%以上。前30min海带对2种离子的吸附速度较快,而后30min吸附速度相对较慢。在同一温度下,相同质量的海带粉对铜离子的吸附量大,对镍离子的吸附量小。海带对铜离子的吸附指数介于0.3～0.5,对镍离子的吸附指数介于0.4～0.6。[结论]该研究为利用生物吸附剂处理工业废水奠定了理论基础。     

纳豆激酶的亲和吸附工艺研究

采用静态吸附方法验证了大豆颗粒对纳豆激酶的亲和吸附特性,测定了其静态吸附动力学特性和吸附等温线以及一些吸附条件。结果表明:该亲和吸附等温线符合Langmiur方程,吸附动力学符合扩散方程;吸附的最佳缓冲液选择pH6.0、0.01 mol.L-1的PBS,在静态时选用大豆颗粒的最大吸附量为6351.58 IU.g-1,洗脱后收率达到81.30%,纯化倍数约30.23倍。初步推断大豆蛋白中含有与纳豆激酶特异性吸附的的配体结构。     

茶叶炭化物对有机污染物质吸附性能的研究

以茶叶粉为原料,在250-400℃下炭化制得茶叶炭化物。研究结果表明,随着炭化温度和保温时间的增加,炭化物的得率呈不断下降的趋势。随着温度的升高,氨和甲醛的吸附值呈现先升后降的趋势,在300℃时达到最大,而苯吸附值呈现不断上升的趋势。在实验条件下,保温时间的延长反而不利于炭化物对苯、甲醛、氨的吸附。     

Transport and adsorption of antibiotics by marine sediments in a dynamic environment

Background, aim, and scope  Bed sediments are the major sink for many contaminants in aquatic environments. With increasing knowledge of and research on the environmental occurrence of antibiotics, there has been growing interest in their behaviour and fate in aquatic environments. However, there is little information about the behaviour of antibiotics in a dynamic water/sediment environment, such as river and coastal marine water. Therefore, the aims of the present study were: (1) to study the transport and distribution of four common antibiotics between water and sediment in both dynamic and quiescent water/sediment systems and (2) to understand the persistence and possible degradation of the four antibiotics in the two different systems. Materials and methods  A lid-driven elongated annular flume, designed to reduce the centrifugal effect, was used to simulate a dynamic water environment. In addition, a quiescent water/sediment experiment was conducted for comparison with the dynamic water system. The seawater and sediment, used in both experiments of flowing and quiescent water/sediment systems, were collected from Victoria Harbour, a dynamic coastal environment in an urban setting. The four antibiotics selected in this study were ofloxacin (OFL), roxithromycin (RTM), erythromycin (ETM), and sulfamethoxazole (SMZ), the most commonly used antibiotics in South China. Results and discussion  Antibiotics in an overlying solution decreased very quickly in the flume system due to the sorption to suspended particles and surface sediment. There were significant differences in the adsorption of the four antibiotics in sediment. OFL showed a high tendency to be adsorbed by sediment with a high K _d value (2980 L/Kg), while the low K _d values of SMZ indicated that there was a large quantity in water. The four antibiotics reached a depth of 20–30 mm in the sediment over a period of 60 days in the flume system. However, the compounds were only found in surface sediment (above 10 mm) in the quiescent system, indicating the influence of the dynamic flume system on the distribution of antibiotics in sediment. OFL showed a moderate persistence in the dynamic flume system, while other three antibiotics had less persistence in sediment. However, all of the four compounds showed moderate persistence in the quiescent system. Recommendations and perspectives  The study showed the rapid diffusive transfer of antibiotics from water to sediment in the dynamic flume system. The four antibiotics exhibited larger differences in their adsorption to sediment in both dynamic and quiescent systems due to their different K _d values. The high sorption of antibiotics to marine sediment may reduce their availability to benthic invertebrates.     

Comparison of Gypsum and Sulfuric Acid for Sodic Soil Reclamation

In some field and laboratory studies , H2SO4 has shown better reclamation efficiency than gypsum, but the explanation for this has been debated. We tested the hypothesis that significant amounts of HCO might be formed during the reaction of HSO3 with CaCO3 leading to additional Ca2+ in solution and enhanced displacement of exchangeble Na +. To determine if H2SO4 is more efficient than gypsum , we compared four equivalent treatments of H2SO4 and gypsum on three soils and two clay minerals. Gypsum and H2SO4 were reacted with calcareous sodic soils and clay minerals in closed-system batch studies, with CO2 pressures typical of soil root zones. Column studies comparing two equivalent treatments of H2SO4 and gypsum were conducted on one of the soils and produced results comparable to the batch studies. Soluble ions, electrical conductivities (EC), and mineral saturation indices were determined and compared between treatments . Clay dispersion and average dispersed particle size were compared between amendments on bentonite . When H2SO4 was applied to calcite in the absence of exchangeable sodium (soil), the solution was fourfold oversaturated with respect to gypsum. This was not observed in the soils because the exchange phase of the soil was a sink for Ca2+. In the soils, there was significantly more HCO3 in all H2SO4 treatments, with an average of 8 % of the H+ applied producing H3CO3. The concentration of dispersed clay was significantly less in three of the four H2SO4 treatments on bentonite , while the mean particle diameter was significantly larger in two of the four treatments , suggesting better tactoid preservation . Compared to equivalent soil gypsum treat ments, H2SO4 generally caused (1) lower sodium adsorption ratios , (2) more soluble Ca 2+ and Mg2+, (3) lower pH , and (4) greater EC. In the calcareous sodic soils and clays we tested , it appears gypsum supersaturation , HCO3 production , lower pH , and higher EC frequently contributed to better reclamation with H2SO4.     

污泥热解工艺参数对残渣吸附性能的影响

[目的]优化污泥热解工艺条件及增强污泥热解残渣对小分子的吸附性能。[方法]设置不同的温度、保温时间及含水率条件,对污泥进行热解,测定不同条件下得到的热解残渣的失重率、热值、碘吸附值、亚甲基蓝吸附值等指标。[结果]污泥中有机质发生热解反应的主要温度为350～550℃;温度越高,热解剩余残渣率和残渣热值越低,污泥热解越充分;在450℃时,污泥热解残渣的吸附性能最好。当保温时间延长到60 min以后,对热解结果的影响不大,从节能的角度考虑,保温时间应设定为60 min。当含水率增加到50%以后,对热解结果的影响不大,从节能的角度考虑,应将污泥含水率控制在50%之内。[结论]该研究为污泥无害化与资源化处理提供了参考依据。     

不同粒级土壤团聚体对砷(Ⅴ)的吸附与解吸影响研究

本文以辽宁省朝阳市日光温室耕层土壤作为研究对象,探讨不同粒径团聚体对土壤中砷(As(Ⅴ))吸附解吸的影响.结果表明,不同粒级团聚体对As(Ⅴ)的吸附和解吸能力均符合Freundlich拟合方程,R2介于0.9528 ～0.9972之间,其中＜53μm粒径团聚体对As(Ⅴ)的吸附、解吸能力最强,并随着粒径的增大,吸附、解吸能力均降低,且不同粒径对As的吸附与解吸能力呈显著正相关关系.随着溶液中As(Ⅴ)的浓度的提高,各粒径团聚体对As(Ⅴ)的吸附、解吸能力均提高,K值介于17.75 ～50.51之间.不同粒级团聚体对As(Ⅴ)的吸附量与土壤有机质含量、游离氧化铁含量及CEC含量之间均呈正相关关系,说明团聚体对As(Ⅴ)的吸附受到土壤团粒胶结剂的影响.     

天然纤维材料改性及其吸附抗生素的应用研究

以花生壳、木屑这些天然纤维材料制备吸附剂吸附废水中的四环素类抗生素,通过探讨改性剂种类、改性剂用量、改性时间等因素对吸附效果的影响,筛选出最佳吸附材料并优化改性方案。实验结果表明,两种吸附剂对抗生素废水均有较高的吸附效率,其中碱改性花生壳的吸附效果最好,最佳改性方案为1 mol·L-1 NaOH室温下改性5 h,对3种四环素类抗生素的去除率分别为土霉素67.27%、四环素79.08%、强力霉素87.40%。同时,利用傅立叶红外光谱（FTIR）和扫描电镜（SEM）对碱改性花生壳结构特性进行表征,推断碱改性花     

Retention and Uptake by Plants of Added Selenium in Peat Soils

In soil, adsorption of selenium (Se) onto mineral surfaces is accompanied by poorly known retention via organic matter. The effects of these components on the availability of Se were examined in two pot experiments. Spring wheat was grown with increasing amounts of selenate (SeO₄ ^2–) in one sand and three peat soils, and ryegrass with selenate and selenite (SeO₃ ^2–) in sphagnum peat manipulated by iron (Fe) hydroxide. Selenate persisted in soluble form, whereas selenite was fixed in the soil. In wheat, 5–50% of the selenate addition was recovered in the plant, the proportion increasing with increasing Se. In ryegrass, 30–40% of the added selenate but less than 2% of the selenite was found within the leaves. The Fe hydroxide enrichment enhanced the selenite uptake. Phosphate buffer desorbed a minor proportion of the added selenite, except in peat amply enriched with Fe hydroxide. The results suggest that the retention mechanism of selenite was changed due to the hydroxide amendment.