不同菌糠生物炭对水体中Cu2+、Cd2+的吸附性能

以菌糠废弃物为原料,采用限氧裂解法在500℃条件下制备香菇菌糠、猴头菇菌糠和平菇菌糠生物炭(LEBC、HEBC和POBC).利用SEM、XRD和FTIR等方法对吸附剂进行了表征;通过吸附动力学、等温吸附、生物炭酸化实验探究了3种菌糠生物炭去除水溶液中Cu~(2+)、Cd~(2+)的效果及机理.结果表明,在溶液初始pH 2—3时,3种菌糠生物炭对溶液中Cu~(2+)、Cd~(2+)的吸附量急剧增加.LEBC、HEBC、POBC对Cu~(2+)、Cd~(2+)的吸附符合准二级动力学模型,对Cu~(2+)的吸附速率分别为10.15×10~(-3)、7.08×10~(-3)、0.69×10~(-3) mg·g~(-1)·min~(-1),对Cd~(2+)的吸附速率分别为6.53×10~(-3)、5.19×10~(-3)、0.26×10~(-3) mg·g~(-1)·min~(-1).不同浓度下LEBC、HEBC、POBC对Cu~(2+)的吸附符合Langmuir模型,最大吸附量依次为56.74、11.98、77.32 mg·g~(-1);而Cd~(2+)的吸附符合Freundlich模型,最大吸附量依次为74.26、36.49、70.2 mg·g~(-1).LEBC在较短的时间内能达到较大的吸附量,可作为去除水体中Cu~(2+)、Cd~(2+)的优质吸附剂.XRD和FTIR等分析结果表明生物炭对Cu~(2+)、Cd~(2+)的吸附机制包括物理吸附、阳离子-π作用、官能团络合及沉淀.3种生物炭经酸化处理后,对Cu~(2+)、Cd~(2+)的吸附能力显著下降,表明生物炭中碳酸盐引起的Cu~(2+)、Cd~(2+)表面沉淀在吸附过程中起重要作用.     

改性稻壳生物炭对水中Cd2+的吸附性能研究

为提高生物炭对水中Cd2+的吸附去除性能,以BC1和BC22种稻壳生物炭为基础材料,分别采用NaOH和FeCl3溶液制备得到NBC1和NBC2以及FBC1和FBC2改性稻壳生物炭,并通过吸附动力学和等温吸附实验研究6种生物炭对水中Cd2+的吸附性能.结果表明,对于50 mg·L-1 Cd2+溶液,当生物炭投加量为1 g...     

乙醇和氢氧化钠预处理对面包酵母菌吸附Cu2+的影响

研究了面包酵母菌及由无水乙醇和氢氧化钠分别处理的面包酵母菌对Cu2 的生物吸附作用.结果表明,菌样在pH 5,菌量1g·1-1,吸附时间20min,Cu2 25mg·1-1时,最大吸附量分别为2.42,3.3和5.73mg·g-1,吸附过程符合Langmuir等温吸附模型.菌主要依靠表面活性基团吸附Cu2 .预处理作用增加了菌表面活性基团的数量及活性.在吸附过程中静电作用可能对吸附有一定的影响.另外,菌样对Cu2 的吸附以可逆吸附为主,并不同程度地存在不可逆吸附.     

添加农作物秸秆炭对红壤吸附Cu(Ⅱ)的影响

为考察秸秆生物质炭在重金属污染红壤修复中的作用,用一次平衡法研究了由花生秸秆、大豆秸秆、稻草和油菜秸秆制备的4种生物质炭对采自江西和广西的2种红壤吸附Cu(Ⅱ)的影响及其机制。结果表明,添加由农作物秸秆制备的生物质炭提高了红壤对Cu(Ⅱ)的吸附量,生物质炭对Cu(Ⅱ)吸附的促进作用随生物质炭添加量的增加而增加,低pH值条件下促进作用更明显。pH值4.0和w为2%生物质炭添加水平下,油菜秸秆炭、花生秸秆炭、大豆秸秆炭和稻草炭使江西红壤对Cu(Ⅱ)的吸附量较对照分别增加97%、79%、51%和54%;花生秸秆炭和大豆秸秆炭使广西红壤对Cu(Ⅱ)的吸附量较对照分别增加61%和44%,当生物质炭添加水平w达4%时,Cu(Ⅱ)吸附量的增幅达97%和165%。生物质炭表面带负电荷,可以同时增加红壤对Cu(Ⅱ)的静电吸附量和专性吸附量,但以增加专性吸附为主。因此,添加秸秆生物质炭可以有效降低Cu(Ⅱ)在酸性红壤中的活动性和生物有效性。     

不同作物原料热裂解生物质炭对溶液中Cd2+和Pb2+的吸附特性

选择由小麦秸秆、玉米秸秆和花生壳经350~500℃热裂解制成的生物质炭,研究生物黑炭对水溶液中Cd2+和Pb2+的吸附特性,分析了pH值、吸附时间、溶液初始质量浓度、生物质炭粒径和投加量对吸附效果的影响。结果表明:生物质炭对Cd2+和Pb2+的吸附约10 min即达平衡;3种生物质炭对Cd2+和Pb2+的等温吸附均可用Langmuir方程和Freundlich方程拟合,玉米秸秆炭对Cd2+和Pb2+的最大吸附量远大于小麦秸秆炭和花生壳炭;在生物黑炭投加量为150 mg(6 g.L-1)时,3种生物黑炭对溶液Cd2+的去除率均在90%以上,玉米秸秆炭对溶液Pb2+的去除率达90.30%,而小麦秸秆炭和花生壳炭的去除率仅为52%和47%,玉米秸秆炭有望成为处理重金属污染废水的新型吸附材料。     

黄泥土和乌栅中不同粒径微团聚体对Cu2+的吸附与解吸

用平衡吸附法研究了黄泥土和乌栅土的不同粒径微团聚体对Cu2 的吸附和解吸.结果表明,不同粒径微团聚体对Cu2 的吸附特性均符合Freundlich和Langumir方程,最大吸附量介于1667-3333 mg·kg-1之间,以粘粒级和粗砂级为最大,其对Cu2 的固持能力高于其它粒径的微团聚体.随着溶液中Cu2 浓度的升高,吸附率出现不同程度的降低.对同一粒径颗粒的Cu2 吸附量来说,乌栅土高于黄泥土,而解吸量则相反.微团聚体颗粒对Cu2 的吸附容量与有机质、游离氧化铁含量呈显著正回归关系,说明团聚体颗粒对重金属的吸附首先受土壤团聚体胶粘剂的控制.     

酿酒酵母对Cu2+生物吸附机制的研究

采用废啤酒酵母分析了pH值、加菌量等影响啤酒酵母吸附Cu2 的主要因素,结果表明:pH4.5,吸附时间1—1.5h,加菌量0.01g·ml-1为最佳吸附条件;酵母对Cu2 的吸附符合Langmuir模型,表现为单分子层吸附;酵母菌细胞壁表面的—COOH,—NH3以及脂肪在其吸附铜离子时起着重要作用,NaOH处理的酵母吸附能力大大增加.     

施加Fe2+和Cu2+对鸡爪槭叶色变化的生理影响

研究金属元素Cu2+和Fe2+对彩叶树种鸡爪槭(Acer palmatum Thunb.)叶片呈色效果的影响,为彩叶树种的秋季叶色调控和养护管理提供理论依据.于2018年5月开始进行盆栽试验,分别采用浓度0.3％和0.6％CuSO4·5H2O、0.3％和0.6％FeSO4·7H2O对鸡爪槭进行叶面施肥.测定鸡爪槭叶片变...     

人居生活废弃物生物黑炭对水溶液中Cd2+的吸附研究

以人居生活废弃物生物黑炭为材料,探讨生物黑炭对Cd2+的吸附动力学及热力学特性,通过平衡吸附法研究吸附时间、Cd2+初始质量浓度、吸附剂投加量、溶液pH值以及黑炭粒径对Cd2+吸附率的影响.结果表明,吸附时间为2h时基本达到吸附平衡,准二级动力学方程能很好地描述生物黑炭对Cd2+的吸附过程.Langmuir模型能较好地描述生物黑炭对Cd2+的等温吸附过程,根据该模型模拟得到25℃条件下Cd2+最大吸附量为6.22mg·g-1.Cd2+去除率随生物黑炭投加量的增加而增大;生物黑炭对Cd2+吸附量随其粒径减小而增大;溶液初始pH值为4.0～7.5时,pH值变化对Cd2+吸附量的影响不显著.采用人居生活废弃物生物黑炭去除水溶液中Cd2+时,控制溶液Cd2+初始质量浓度30mg·L-1,粒径小于0.25 mm,投加水平8g·L-1,反应温度25℃,反应时间1～2h,Cd2+去除率可达80％.人居生活废弃物生物黑炭可以作为去除污染水体中Cd2+的吸附剂.     

离子强度对土壤与沉积物吸附多环芳烃的影响研究

以黄河三角洲表层沉积物与湿地土壤为对象,研究了离子强度对菲、苯并[a]芘在土壤和沉积物上吸附行为的影响。结果表明:不同Ca2 离子强度下,土壤与沉积物对菲、苯并[a]芘的吸附速率均较快,48h吸附能够达到平衡,Ca2 离子强度对土壤和沉积物影响程度不同;土壤和沉积物的吸附等温线均呈线形,能较好地符合线性方程,可决系数R2在0.98以上,菲的KD值在24~130mL·g-1之间,苯并[a]芘的KD值在3517~5081mL·g-1;随着体系离子强度的增大,土壤与沉积物对PAHs的吸附能力均降低,而且两者之间的吸附量差距明显降低,表明离子强度对土壤影响程度明显大于沉积物。     

Effects of organic acids on Cd adsorption and desorption by two anthropic soils

The objective of this experiment was to study the effects of malic, tartaric, oxalic, and citric acid on the adsorption and desorption characteristics of Cd by two typical anthropic soils (lou soil and irrigation-silted soil) in North-west China. Cadmium adsorption and desorption were studied under a range of temperatures (25°C, 30°C, 35°C, 40°C), organic acid concentrations (0.5–5.0 mmol·L^-1), and pH values (2–8). The results showed that the Cd adsorption capacity of the lou soil was significantly greater than that of the irrigation-silted soil. Generally, Cd adsorption increased as the temperature increased. In the presence of NaNO₃, the adsorption of Cd was endothermic with ΔH values of 31.365 kJ·mol^-1 for lou soil and 28.278?kJ·mol^-1 for irrigation-silted soil. The endothermic reaction indicated that H bonds were the main driving force for Cd adsorption in both soils. However, different concentrations of organic acids showed various influences on the two soils. In the presence of citric acid, chemical adsorption and van der Waals interactions were the main driving forces for Cd adsorption rather than H bonds. Although the types of organic acids and soil properties were different, the effects of the organic acids on the adsorption and desorption of Cd were similar in the two soils. The adsorption percentage of Cd generally decreased as organic acid concentrations increased. In contrast, the adsorption percentage increased as the pH of the initial solution increased. The exception was that adsorption percentage of Cd increased slightly as oxalic acid concentrations increased. In contrast, the desorption percentage of Cd increased with increasing concentrations of organic acids but decreased as the initial solution pH increased.     

Effects of Hg2+ and Cu2+ on the cytosolic Ca2+ level in molluscan blood cells evaluated by confocal microscopy and spectrofluorimetry

In the present work the effect of Hg²⁺ and Cu²⁺ on the level of cytosolic Ca²⁺ in mussel (Mytilus edulis L.) haemolymph cells were investigated by confocal microscopy and spectrofluorimetry utilizing the fluorescent dye Fluo3. In the blood cells of marine molluscs, exposure to Cu²⁺ and Hg²⁺ in the nanomolar and micromolar range causes a time-and concentration-dependent increase in the cytosolic Ca²⁺ level. Both the presence of a low-calcium containing medium and pretreatment of the cells with the channel blocker Verapamil greatly reduced the effects of higher (50 M) Hg²⁺ concentrations, this indicating that Hg²⁺ enhances the influx of extracellular Ca²⁺ partly through activation of voltage-dependent Ca²⁺ channels. Low concentrations of Hg²⁺ (1 M) and also of Cu²⁺ (0.5 M), an essential element, were able to induce a sustained increase in cytosolic Ca²⁺, which was not affected either by Verapamil pretreatment or by lowering the extracellular calcium concentration. These data indicate that in mussel haemocytes heavy metal cations impair Ca²⁺ homeostasis not only by affecting Ca²⁺ channels, but also by interfering with other mechanisms of calcium transport across cellular membranes, such as the Ca²⁺-ATPases. The resulting increase in cytosolic Ca²⁺ could activate Ca-dependent processes which may be involved in many of the biochemical and physiological alterations observed in the cells of metal-exposed mussels. Specimens used in these experiments were collected from the river Linker near Plymouth, U.K. in June 1991.     

CrO42-对两种可变电荷土壤吸附钾的影响

用一次平衡法研究了CrO4^2-对两种可变电荷土壤吸附钾的影响，用火焰光度法测定平衡溶液中的钾，根据差减法计算土壤对钾的吸附量。结果表明，加入铬酸根能增加土壤对钾的吸附量。铬酸根对钾吸附的影响程度与土壤游离氧化铁含量和土壤对铬酸根的吸附量的大小有关。砖红壤游离氧化铁含量高于红壤，它对铬酸根的吸附量也大于红壤，因此，铬酸根对砖红壤吸附钾的影响程度大于红壤。CrO4^2-主要通过自身的吸附增加土壤的表面净负电荷，并从而增加土壤对钾的吸附量。     

几种土壤的基本理化性质与Cu2+吸附的关系

研究了大冶市几种类型土壤的基本性质及与Cu2+吸附的关系,结果表明,土壤对Cu2+的吸附量随其CEC值(记为CEC)而变化,供试土壤的Cu2+吸附量由大到小的顺序为石灰土→水稻土→潮土→棕红壤.加入铜浓度为5 mmol·L-1时11个土壤对铜的吸附量x((mol·g-1)与CEC的直线相关方程为x(Cu2+) = 2.018×CEC + 24.4 (r=0.7066).而影响CEC的因素,如Ph、粘粒含量及其组成、有机质、比表面等,也是决定Cu2+吸附量的重要因素.     

模拟酸化下水稻土微团聚体Cu2+吸附与解吸的影响

采用低能量超声波分散和冷冻机干燥法提取太湖地区水稻土(黄泥土)微团聚体颗粒,用平衡液吸附法和CaCl2与HCl溶液的连续解吸法研究了它们在pH2～6范围内pH对Cu2 的静电吸附和专性吸附的影响。结果表明,不同粒径的微团聚体颗粒对Cu2 的吸附等温线可都用Freundlich模型来描述。Cu2 吸附量大小以下序递减,粘粒级、砂粒级、粉砂级、粗粉砂级;吸附量受其中游离氧化铁、氧化铝和有机质含量的控制。吸附量随pH升高而增加。低pH条件下利于静电吸附,吸附过程H 减少使平衡液pH上升;高pH条件下主要是专性吸附所控制,释放H 使平衡液pH下降。     

长江重庆段表层水体中多环芳烃的分布及来源分析

采集了长江重庆段干流以及重要支流共7个断面的表层水样,采用液相色谱法分析15种优先控制的多环芳烃(PAHs).结果表明,水体中总PAHs浓度范围为6.44—109.39 ng·L-1,平均值为41.83 ng·L-1.在5个断面水体中检出苯并(a)芘,浓度为0.05—1.32 ng·L-1,低于我国地表水标准限值(2.8 ng·L-1).长江重庆段的PAHs浓度水平低于大部分国内其他河流,与国外一些河流的浓度水平相当.PAHs组成以中低环PAHs(3环和4环)为主,平均比例分别为55.7%和38.8%,高环PAHs(5环和6环)含量较低,分别占3.6%和1.9%.示踪PAHs比值法结果显示长江重庆段表层水体PAHs主要来源于石化产品的泄漏污染.     

Biosorption of Cd2+ and Cu2+ on immobilized Saccharomyces cerevisiae

The biosorption of Cd²⁺ and Cu²⁺ onto the immobilized Saccharomyces cerevisiae (S. cerevisiae) was investigated in this study. Adsorption kinetics, isotherms and the effect of pH were studied. The results indicated that the biosorption of Cd²⁺ and Cu²⁺ on the immobilized S. cerevisiae was fast at initial stage and then became slow. The maximum biosorption of heavy metal ions on immobilized S. cerevisiae were observed at pH 4 for Cd²⁺ and Cu²⁺. by the pseudo-second-order model described the sorption kinetic data well according to the high correlation coefficient (R ²) obtained. The biosorption isotherm was fitted well by the Langmuir model, indicating possible mono-layer biosorption of Cd²⁺ and Cu²⁺ on the immobilized S. cerevisiae. Moreover, the immobilized S. cerevisiae after the sorption of Cd²⁺ and Cu²⁺ could be regenerated and reused.     

Pb2+、Cd2+和Cr(Ⅵ)抑制球形红细菌生长的毒性效应

运用评价化学品对水生生物毒性的标准方法,得到Pb2 、Cd2 和Cr(Ⅵ)对球形红细菌生长的最小无差异浓度(LNOEC)分别为85.9mgL-1、22.1mgL-1和17.7mgL-1.根据实验结果采用几率单位进行数据处理,得到抑制球形红细菌生长的96hEC50分别为195.0mgL-1、91.2mgL-1和77.6mgL-1,并对各剂量反应方程进行χ2检验,结果均符合精度要求,计算出的96hEC50真实可靠.研究结果表明,抑制球形红细菌生长的毒性由大到小的顺序是Cr(Ⅵ)>Cd2 >Pb2 .不同金属离子与细胞壁亲和性不同或能通过菌体内生物化学转化形成沉淀,可能是导致金属离子抑制球形红细菌生长毒性差异的主要原因.图1表2参15