褐藻酸钠对Cu2+、Pb2+交换与吸附性能的研究

本文研究了褐藻酸钠与Ｃｕ＾２＋,Ｐｂ＾２＋交换行为,通过海藻酸钠溶液与Ｃｕ＾２＋,Ｐｂ＾２＋的絮凝,测得两种离子最大交换量。考察了褐藻酸钠固体粉末与Ｃｕ＾２＋,Ｐｂ＾２＋在不同的反应条件下的离子交换与吸附行为。实验表明ｐＨ值,温度,时间,配比等条件是影响交换与吸附的因素,其吸附行为在一定的温度和一定的浓度范围内能较好的符合Ｆｒｅｕｎｄｌｉｃｈ等温吸附式。     

氨基化锰铁氧体纳米粒子的制备及吸附pb2+和Cd2+性能研究

利用一步水热法合成了氨基化锰铁氧体纳米粒子吸附材料,并研究了对Pb₂₊和Cd₂₊的吸附特性和去除效果;通过SEM、XRD、 FT-IR和XPS等方法进行了表征分析和吸附机理研究。结果表明：温度为25 ℃,氨基化锰铁氧体纳米粒子吸附Pb₂₊和Cd₂₊在60 min内即可达到吸附平衡,最大饱和吸附量分别为255.57 mg?g_-1和129.72 mg?g_-1;吸附过程符合准二级动力学方程和Langmuir等温吸附方程,对Pb₂₊和Cd₂₊的吸附过程主要是单分子层化学吸附。氨基化锰铁氧体纳米粒子吸附-再生重复利用5次后,对Pb₂₊和Cd₂₊的吸附量分别仍为初始吸附量的87%以上,表现了良好的再生吸附性能。     

氧化多壁碳纳米管对Pb2+的吸附性能研究

该文研究了氧化多壁碳纳米管(o-MWNTs)对Pb2+的吸附性能,考察了平衡时间、溶液pH值、溶液体积等因素对吸附行为的影响。在静态吸附条件下:Pb2+能大量并快速地被o-MWNTs吸附,45 min内即可达到吸附平衡,而活性炭(ACs)的吸附平衡时间为90 min。溶液pH值在1.0~7.0范围对吸附量有显著影响,在pH5.0~6.0时o-MWNTs对Pb2+的静态吸附容量为17.43 mg.g-1。o-MWNTs对铅离子的吸附量随着溶液体积的增加而增加,并逐渐趋于稳定,最大吸附量可达25 mg.g-1。在动态吸附实验中,30 mg.L-1的铅离子溶液在SPE小柱的穿透体积为235 mL,溶液体积为400 mL时可完全穿透。动态吸附实验表明,o-MWNTs对铅离子具有较大的吸附容量且萃取回收率高达94%。研究表明,氧化碳纳米管装填的固相萃取小柱可用于中药提取物中Pb2+的残留分析。     

ZnCl2、KOH和HNO3改性MWCNT对苯酚的吸附行为研究

通过扫描电子显微镜、X射线衍射仪、N₂吸附分析仪及Boehm滴定法获得ZnCl₂、KOH和HNO₃化学处理对高纯多壁碳纳米管的结构和表面含氧官能团的影响,通过批处理实验考察吸附条件（吸附时间、初始浓度、温度）对处理前后的碳纳米管吸附苯酚行为的影响,并采用准一级、准二级、Evolich动力学模型和热力学方程拟合其吸附数据,分析其动力学行为、热力学行为和吸附机理。结果表明,虽然ZnCl₂、KOH和HNO₃化学处理法均未对碳纳米管BET比表面积产生显著影响,但会影响其表面化学性质（即,对于ZnCl₂和KOH化学处理降低表面羧基、内酯基含量和增大碱性官能团量,而对于HNO₃化学处理可以增大表面羧基、内酯基含量,而碱性官能团略有增加）;改性处理影响碳纳米管去除苯酚效率：由于ZnCl₂和KOH改性处理降低碳纳米管表面羧基量,故其提高了苯酚去除率,而HNO₃处理则略减小碳纳米管的苯酚去除率,可能是由于碳纳米管结构和表面化学性质共同影响所致;碳纳米管的苯酚去除率均随苯酚溶液初始浓度的增大而减小;高温不利于吸附;热力学研究发现碳纳米管吸附苯酚过程是自发的和放热的,属于物理吸附;动力学研究表明,吸附过程符合准二级动力学方程。通过ZnCl₂和KOH化学处理,可以显著提高碳纳米管对苯酚的吸附性能。     

改性生物凝胶对重金属离子的吸附性能研究

以桔子汁加工残渣为原料,制备钙型和氢型生物凝胶作为吸附剂,用于去除水溶液中的重金属离子.结果表明,上述凝胶在水溶液中稳定性较好,对重金属离子的吸附性能优良.钙型凝胶的吸附选择性顺序为:Fe3 ＞Pb2 ＞Cd2 ＞Zn2 ,饱和吸附容量分别为:Pb2 、Cd2 、Zn2 均为约1.1mmol/g、Fe3 为1.5mmol/g;氢型凝胶的吸附选择性顺序为:Pb2 ＞Zn2 ＞Cd2 .钙型凝胶对Fe3 的吸附行为明显不同于氢型凝胶,钙型凝胶以离子交换机理以及Fe3 与Ca2 之间的共沉淀作用为主;而氢型凝胶对Fe3 的吸附则以离子交换机理为主.     

水稻秸秆的改性及其对重金属Cu2+的吸附

重金属Cu2+可直接或间接危害人体,作为天然吸附剂的农业废弃物因价廉易得、来源广泛、吸附高效等优点备受青睐。本文选用水稻秸秆（RS）为吸附原料,分别经酸、碱改性后得到H2SO4-RS和NaOH-RS,通过FT-IR、SEM和BET对改性前后吸附材料的表面官能团、表观形貌和结构等理化性质进行分析,考察投加量、吸附时间、初始Cu2+浓度和离子强度对吸附效果的影响,并结合吸附动力学、吸附等温线和热力学模型对吸附过程进行探讨。结果表明：改性水稻秸秆对Cu2+达到吸附平衡所需的投加量和时间较之未改性RS大大减少,去除率由42.0%分别提升至85.9%（H2SO4-RS）和90.0%（NaOH-RS）;随初始Cu2+浓度和离子强度的增大,RS的吸附性能显著降低,H2SO4-RS有所降低,而NaOH-RS只是稍有下降,NaOH-RS对150 mg/L含Cu2+溶液的去除率仍达到84.2%,离子强度cNaCl = 0.1 mol/L时去除率维持在86.1%。吸附动力学和吸附等温实验表明水稻秸秆对Cu2+的吸附符合准二级动力学模型和Langmuir吸附等温模型;热力学分析显示,相同温度下RS、H2SO4-RS和NaOH-RS吸附Cu2+过程的ΔG逐渐减小,且改性后两种吸附剂的ΔG均小于0,ΔH由改性前的正值转变为负值,说明水稻秸秆改性后吸附Cu2+的自发性更强,为自发的放热过程。     

生物材料对重金属离子的吸附富集作用

介绍了重金属离子的生物吸附富集作用,从生物材料的类型、生物吸附的选择性、化学修饰与生物吸附、生物对重金属离子的浓缩富集作用和生物吸附的机理及模型等方面作了说明。利用生物材料可去除水体中的重金属离子。     

改性壳聚糖的制备及对Cu2+Pb2+的吸附研究

用巯基乙酸作为巯基化剂,对壳聚糖进行改性,选择了巯基化的条件.实验表明,在浓度为188mg/L的铜溶液中,CTS-SH的最大吸附率达90.3%以上,吸附容量为27.76mg/g,在浓度为203mg/L的铅溶液中,对铅的最大吸附率达到99%以上,在浓度为1.015g/L的铅溶液中,最大吸附率达95.5%.此时的吸附容量为97.4mg/g,吸附容量大于147.2mg/g时的吸附率为36.3%.经XRD及EMS图片的分析,可以看出,改性壳聚糖在吸附前后,结构发生了改变.     

壳聚糖对Zn2+的吸附性能研究

本文用壳聚糖对Ｚｎ＾２＋的吸附条件进行了研究,探讨了脱乙酰度,分子量,粒度大小,溶液的ｐＨ值,温度,Ｚｎ＾２＋起始浓度和不同锌盐等方面对壳聚糖吸附性能的影响。结果表明：壳聚糖对Ｚｎ＾２＋的吸附具有Ｌａｎｇｍｕｉｒ吸附特征,其吸附最佳条件是壳聚糖脱乙酰度为１００％,锌盐为硫酸锌,Ｚｎ＾２＋溶液ｐＨ值为６．０,起始浓度４－５ｍｇ／ｍｌ。     

谷壳对水中Cr(Ⅵ)离子的生物吸附研究

以间歇吸附的方式考察农业副产物谷壳对模拟废水中Cr(Ⅵ)离子的生物吸附过程,用扫描电镜(SEM)、红外光谱(FTIR)分析谷壳的表面形态和表面官能团结构及其变化,探讨其吸附机理。结果表明,吸附反应符合Langmuir和Freunlich等温吸附模式、遵循拟二级动力学模型,Cr(VI)离子的最大去除率几乎可以达到100%,吸附过程包括物理吸附和化学吸附。用0.2mol/L的NaOH溶液解吸再生的谷壳,吸附能力增加,可以循环使用。     

Study of sorption of Pb2+, Cd2+, Zn2+ and Cu2+ from wastewater on synthetic analogues of clintonite

The study describes a sorption of metal ions Pb²⁺, Cd²⁺, Zn²⁺ and Cu²⁺ on a synthetic mica clintonite. Synthesis of analogues of clintonite was carried out by using inorganic salts as sources of silicon and aluminum in the hydrothermal method. Alkaline conditions were applied to increase the nucleation rate. Powdered clintonite obtained after mechanical grinding was used for the removal of metal ions from the wastewater. The sorption experiments were done under batch process to measure the concentrations of metal ions. Effects of pH, contact time between sorbent and sorbate solution, amount of sorbent and temperature on the sorption of metal ions were studied. The sorption was shown to increase with the pH of the medium. The optimal conditions for sorption of metal ions on synthetic analogues of clintonite were determined.     

Study of the kinetics and mechanism of Sr2+ sorption by clinoptilolite

Journal of Radioanalytical and Nuclear Chemistry - The parameters of kinetics of Sr2+ sorption by natural clinoptilolite were investigated. The overall rate constants were determined by application...     

离子选择电极法研究钙调素与重金属铅的结合平衡

用Pb2 选择电极法首次测定了CaM与Pb2 的结合常数,结果说明:Pb2 在CaM中约有10个结合位点,与文献报道的一致。其中包括4个强结合位点,结合常数在107量级,对应于Pb2 在CaM中的4个主结合位点;而其余的位点则结合常数较低,对应于Pb2 在CaM中的约6个辅助结合位点。逐级结合常数分别为:K1=2.62×107,K2=3.75×107,K3=1.03×107,K4=1.85×107,K5=2.53×106,K6=8.07×105,K7=3.36×105,K8=2.76×105,K9=2.22×105,K10=3.96×104。由于Pb2 与CaM的4个主结合位点的稳定常数比相应Ca2 的强几十到几百倍,因此Pb2 对Ca2 与CaM的竞争结合作用能够调节CaM的功能。     

Equilibrium models of Cr3+ and Cu2+ with glutamate

Speciation diagrams and stability constants for glutamate (Glu) with (Cr³⁺) and (Cu²⁺) in aqueous solutions are presented. The current study covers a larger pH-range affording accurate results, and reveal a different set of species for Cu²⁺ and species not previously reported for Cr³⁺. For the Cu²⁺ Glu system, the most successful model that refined the potentiometric data contains the simple one-to-one complex, the bis-complex and the mono-hydroxo complex. The overall stability constants for Cu²⁺–Glu complexes have respective values of log β₁₁₀ = 7.6 ± 0.2, log β_11-1 = 1.3 ± 0.7, log β₁₂₀ = 13.6 ± 0.2. Attempts to refine the stability constant for the mono-protonated metal complex (log β₁₁₁) that was reported in the literature indicated that this mono-protonated species did not form to an appreciable amount to be important for the model presented here. For the Cr³⁺ Glu system, the overall stability constants for the complexes formed have the values of log β₁₁₀ = 8.34 ± 0.03, log β_11-1 = 1.9 ± 0.1 and log β_11-2 = ?4.6 ± 0.1. These results for Cr³⁺ system covers wider pH-range and have more accuracy than those reported previously. The NMR experiments for Glu revealed downfield shifts of all protons as pH values decrease from 11.21 to 2.85.     

Ratiometric detection of Cr3+ and Hg2+ by a naphthalimide-rhodamine based fluorescent probe

Newly synthesized rhodamine derivatives, L(1) and L(2), are found to bind specifically to Hg(2+) or Cr(3+) in presence of large excess of other competing ions with associated changes in their optical and fluorescence spectral behavior. These spectral changes are significant enough in the visible region of the spectrum and thus, allow the visual detection. For L(1), the detection limit is even lower than the permissible [Cr(3+)] or [Hg(2+)] in drinking water as per standard U.S. EPA norms; while the receptor, L2 could be used as a ratiometric sensor for detection of Cr(3+) and Hg(2+) based on the resonance energy transfer (RET) process involving the donor naphthalimide and the acceptor Cr(3+)/Hg(2+)-bound xanthene fragment. Studies reveal that these two reagents could be used for recognition and sensing of Hg(2+)/Cr(3+). Further, confocal laser microscopic studies confirmed that the reagent L(2) could also be used as an imaging probe for detection of uptake of these ions in A431 cells.     

Cadmium removal from single- and multi-metal (Cd + Pb + Zn + Cu) solutions by sorption on hydroxyapatite

Heavy metal contamination of waters and soils is particularly dangerous to the living organisms. Different studies have demonstrated that hydroxyapatite has a high removal capacity for divalent heavy metal ions in contaminated waters and soils. The removal of Cd from aqueous solutions by hydroxyapatite was investigated in batch conditions at 25+/-2 degrees C. Cadmium was applied both as single- or multi-metal (Cd + Pb + Zn + Cu) systems with initial concentrations from 0 to 8 mmol L(-1). The adsorption capacity of hydroxyapatite in single-metal system ranged from 0.058 to 1.681 mmol of Cd/g of hydroxyapatite. In the multi-metal system competitive metal sorption reduced the removal capacity by 63-83% compared to the single-metal system. The sorption of Cd by hydroxyapatite follows the Langmuir model. Cadmium immobilization occurs through a two-step mechanism: rapid surface complexation followed by partial dissolution of hydroxyapatite and ion exchange with Ca resulting in the formation of a cadmium-containing hydroxyapatite.     

Kinetics of Fe3+ and Cu2+ sorption by fibrous polyampholite

The kinetics of Fe³⁺ and Cu²⁺ sorption from sulfate salt solutions by fibrous polyampholite have been studied.

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Fe³⁺ Cu²⁺ , .

     

三维氮掺杂石墨烯对水中铅和镉的吸附

采用多巴胺(DA)作为还原剂和功能化试剂,进行了氧化石墨烯的功能化,制备了三维结构的氮掺杂石墨烯材料(rGO-DA)。与还原性氧化石墨烯(rGO)对比,rGO-DA具有更大的吸附容量。rGO-DA对Pb~(2+)和Cd~(2+)的吸附容量分别为91.4,43.5 mg/g。考察了吸附时间、pH值、初始浓度对Pb~(2+)和Cd~(2+)吸附效果的影响。结果表明,rGO-DA对Pb~(2+)和Cd~(2+)吸附达到平衡的时间为120 min,最佳pH值为5.0。在Pb~(2+)和Cd~(2+)初始浓度小于30μg/m L时,二者的吸附去除率分别为100%和87.7%。在吸附Pb~(2+),Cd~(2+)后,rGO-DA可轻松从水体中移除。用HCl脱附,循环使用3次后,rGO-DA对Pb~(2+)和Cd~(2+)的吸附容量无明显变化,可再生并重复使用。