氧化石墨烯(GO)表面原位生长二硫化钼(MoS2)材料高效去除Hg(II)

Hg(II)指的是游离的Hg2+及其不稳定的络合物,是厌氧条件下微生物将其转化为毒性更大的甲基汞的主要形式。作为一种超毒性重金属,Hg(II)可对肾脏、肝脏、免疫系统、内分泌系统以及生殖系统造成不可逆的损伤。在此文章中,以氧化石墨烯(GO)为基底,以L-半胱氨酸、钼酸铵、聚乙烯吡咯烷酮(PVP)、葡萄糖为原料,利用水热法于氧化石墨烯(GO)表面原位生长二硫化钼(MoS2)制备GO改性材料(MoS2/GO)。通过扫描电子显微镜(SEM)和x射线光电子能谱(XPS)表征得到MoS2/GO为石墨烯表面原位生长的层状放射性花状结构,对Hg(II)有较好的吸附作用且吸附后MoS2/GO有明显形态变化。MoS2/GO在较宽pH范围内对Hg(II)均有良好的吸附能力,拟二级动力学模型可以更好的描述该吸附过程,这证明MoS2/GO对Hg(II)之间的结合主要为化学作用。Freundlich模型可以很好的描述Hg(II)的吸附行为为多层吸附,PVP作为插层剂起到了一定的作用,25℃下MoS2/GO对Hg(II)的最大吸附容量为868.38 mg/g。该材料原料毒性小、MoS2层间距相对较大,对Hg(II)有着更为优异的去除能力,可较好的应用在含Hg废水处理中。

Effect of Hg(II) and Pb(II) Ions on C-Phycocyanin (<i>Spirulina</i><i>platensis</i>)

Influence of Hg(II) and Pb(II) ions on C-Phycocyanin (C-PC) from cyanobacteria Spirulina platensis was investigated using Fluorescence spectroscopy. Fluorescence measurements demonstrate quenching of C-PC emission by Hg(II) and Pb(II), and blue shifts in the fluorescence spectra. The effect of DNA on the fluorescence of Hg(II)-and Pb(II)-C-PC (from Spirulina platensis) complexes was also studied. It was shown that the fluorescence intensity of Hg-C-PC after addition of DNA gave rise to the fluorescence buildup. At the same time, addition of DNA to the Pb(II)-C-PC complexes showed no such effect. In the case of Hg(II)-C-PC, fluorescence intensity significantly decreases in time, while for Pb(II)-C-PC, decrease of the fluorescence intensity is not significant, but blue shift of the peak takes place.

Chemically Modified <i>Cornulaca monacantha</i>Biomass for Bioadsorption of Hg (II) from Contaminated Water: Adsorption Mechanism

Cornulaca monacantha (CM) a desert plant has been utilized as adsorbent material for the removal of Hg (II) ions from contaminated water after treatment with acrylamide in alkaline medium to form carbamoylethylated Cornulaca monacantha (CECM). Three levels of CECM having different nitrogen content were prepared. The CECM samples were characterized by estimating the nitrogen content. The ability of CECM to adsorb Hg (II) was investigated by using batch adsorption procedure. The data of the adsorption isotherm was tested by the Langmuir, Freundlich and Temkin models. The removal of Hg (II) onto CECM particles could be well described by the pseudo-second order model. The adsorption rate of mercury was affected by the initial Hg (II) ion concentration, initial pH, adsorbent concentration and agitation time as well as extent of modification. The adsorption experiments indicated that the CECM particles have great potential for the removal of Hg (II) from contaminated water. The maximum adsorption capacity, Qmax of the CECM towards Hg (II) ions was found to be 384.6 mg/g at 30?C. Similarly, the Freundlich constant, n was found to be 2.03 at 30°C.

Study on Adsorption of Hg(Ⅱ) by Chinese Walnut(Juglans mandshurica Maxim.) of Biomass Material

[Objective] The aim of the study was to make research on adsorption of Chinese walnut（Juglans mandshurica Maxim.） Shell（CWS） to Hg（Ⅱ） in water.[Method] Shells of Juglans mandshurica Maxim were used as biosorption to remove Hg（Ⅱ） in water solution to explore the influence to adsorption of Hg（Ⅱ） under different conditions,like pH solution,adsorption time,and Hg（Ⅱ）.[Result] The experimental results show that when absorptivity of Hg（Ⅱ） by CWS reached the highest,pH ranged within 5.0-6.0.The adsorptivity decreased as initial Hg（Ⅱ） concentrations increased.Fourier Transform Infrared Spectroscopy（FTIR） spectrum revealed some chemical groups of CWS may affect the adsorption of Hg（Ⅱ）,such as hydroxyl groups,methyl groups,aromatic methoxyl groups,unconjugated carbonyl,and typical aromatic ring,etc.Adsorption equation can be concluded considering the biosorption process relationship with Langmuir and Frendrich isotherm.[Conclusion] The study found that CW could be employed as a promising biosorption to remove Hg（Ⅱ） from aqueous environments.

α,ω-双罗丹宁氧杂烷与Hg(II)的配合物的制备及结构鉴定

报道了α ,ω -双罗丹宁氧杂烷与Hg(II)形成的四个新配合物 ,其结构通过元素分析 ,IR、UV和1 HNMR光谱鉴定 ,金属含量由双硫腙法测定。

Highly Efficient and Selective Removal of Pb（II） ions by Sulfur-Containing Calcium Phosphate Nanoparticles

A facile one-step co-precipitation method was demonstrated to fabricate amorphous sulfurcontaining calcium phosphate （SCP） nanoparticles, in which the sulfur group was in-situ introduced into calcium phosphate. The resulting SCP exhibited a noticeable enhanced performance for Pb（II） removal in comparison with hydroxyapatite （HAP）, being capable of easily reducing 20 ppm of Pb（II） to below the acceptable standard for drinking water within less than 10 min. Remarkably, the saturated removal capacities of Pb（II） on SCP were as high as 1720.57 mg/g calculated by the Langmuir isotherm model, exceeding largely that of the previously reported absorbents. Significantly, SCP displayed highly selective removal ability toward Pb（II） ions in the presence of the competing metal ions （Ni（II）, Co（II）, Zn（II）, and Cd（II））. Further investigations indicated that such ultra-high removal efficiency and preferable affinity of Pb（II） ions on SCP may be reasonably ascribed to the formation of rodlike hydroxypyromorphite crystals on the surface of SCP via dissolution-precipitation and ion exchange reactions, accompanied by the presence of lead sulfide precipitates. High removal efficiency, fast removal kinetics and excellent selectivity toward Pb（II） made the obtained SCP material an ideal candidate for Pb（II） ions decontamination in practical application.

Bioadsorption of Cd (II) from Contaminated Water on Treated Sawdust: Adsorption Mechanism and Optimization

Sawdust (SD) a very low cost material has been utilized as adsorbent material for the removal of Cd (II) from aqueous solutions after treatment with mono methylol urea (MMU) in the presence of zinc chloride as a catalyst to form MMU-SD. The reaction of MMU-SD was carried out under different conditions including MMU/SD molar ratio, catalyst concentration, and reaction time and temperature. Adsorption studies have been carried out to determine the effect of agitation time, pH, adsorbent and adsorbate concentrations on the adsorption capacity of Cd (II) ions onto MMU-SD. Langmuir, Freundlich and Redlich-Peterson isotherm models were applied in the adsorption studies. The experimental data were analyzed using various sorption kinetic models. The removal processes of Cd (II) onto MMU-SD particles could be well described by the pseudo-second order model. The maximum adsorption capacity of Cd(II) onto MMU-SD was 909 mg/g. Similarly, the Freundlich constant 1/n value was 0.45.

Isotherm, Kinetic and Thermodynamic Studies for the Sorption of Mercury (II) onto Activated Carbon from <i>Rosmarinus officinalis</i>Leaves

The present work deals with the equilibrium adsorption of Hg(II) onto carbonized Rosmarinus officinalis leaves (ACROL) as a new adsorbent from aqueous solution and it has been investigated. ACROL samples were prepared by physical carbonization at 773 K for 1 h. Titration method was used to determine the concentration of Hg(II) before and after adsorption onto ACROL by ethylenediaminetetraacetic acid, EDTA, as chelating agent. Batch equilibrium studies were carried out under different experimental conditions such as Hg(II) concentration and temperature. The relationship between the amount of Hg(II) onto ACROL can be described using four tow-parameter isotherm models. The equilibrium sorption data were analyzed using Freundlich, Langmuir, Dubinin-Radushkevich (DRK) and Temkin isotherms. The experimental results were found to fit the Langmuir isotherm model with a monolayer adsorption capacity of 588.2 mg/g at 318 K, while they were found to fit the Freundlich isotherm model at 298 K. The KL was decreased with increasing temperature, indicating a bond strength between Hg(II) and ACROL decreased with increasing temperature and sorption is exothermic. From DRK isotherm, free energy, E, was higher than 31 kJ/mol suggesting the Hg(II) adsorption onto ACROL chemical sorption. The thermodynamic studies revealed that the process is spontaneous nature of Hg(II) adsorption by ACROL and exothermic. The findings from this research show that ACROL has capability to remove Hg(II) from aqueous solutions.

Sesame Husk as Adsorbent for Copper(II) Ions Removal from Aqueous Solution

In this study, the adsorption behavior of copper(II) ions from aqueous solutions onto sesame husk (SH) was investigated. The effect of different parameters such as pH, contact time, adsorbent dosage, adsorbate concentration, temperature and agitation speed was studied. Thermodynamic parameters, equilibrium isotherms and kinetic data have been evaluated. The functional groups and surface morphology of SH adsorbent were characterized by FTIR and SEM. Adsorption equilibrium isotherms were expressed by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) adsorption models and it was found that Langmuir adsorption model fits the experimental data better than Freundlich and D-R models. The adsorption can be best described by the pseudo second-order kinetic model.

Atomic Absorption and Vibrational Spectral Magnetic Studies on the Removal of Cu(II) and Co(II) Ions Using Synthetic Nano Adsorbent Fe₃O₄

Adsorption of Cu(II) and Co(II) from aqueous solutions on synthetic nano Fe3O4 has been studied. The effect of experimental parameters such as initial concentration of the metal ions, adsorbent dosage, contact time and pH has been investigated. Optimum removal efficiency of Cu(II) ion was found to be 97.8% with the dose rate of 1.07 g/L in 60 minutes at pH = 5.5 and for Co(II) ion, it was found to be 99.2% with the dose rate of2.57 g/L in 10 minutes at pH = 5.4. The removal of Co(II) ions require only 10 minutes with the efficient removal of 99.2%, whereas Cu(II) ions require 60 minutes with the maximum removal of 97.8%. In order to understand the effective removal of Cu(II) and Co(II) ions on Fe3O4, room temperature magnetic measurement was carried out using Vibrational Spectrum Magnetometer (VSM), before and after adsorption with a maximum applied magnetic field of 20,000 G.

A Simple Detection of Hg （11） down to ppm Level Employing Rhodamine Hydrazine Impregnated on a Solid-Phase Membrane

In the methanolic solution, the selectivity of rhodamine hydrazide （RhH） was simply switched from Cu2＋ to Hg2＋ ions. For the optimal absorption of RhH onto a solid-phase membrane, pure methanol was used to dissolve RhH prior to the impregnation. Of solid-phase membranes tested, the filter paper was chosen due to its cost-effectiveness and good detection limit of Hg2＋ ion. The detection limit of the RhH impregnated filter paper for the detection of Hg2＋ ion was determined to be under 2 ppm both fluorescent and colorimetric detection.

染料化工废水混凝污泥热解合成碳基复合材料修饰电极检测Hg(II)

利用功能化纳米结构材料修饰电极检测水环境中重金属离子是环境分析领域的研究热点之一。将染料化工废水混凝处理后的铁基污泥经过高温煅烧改性得到碳基复合材料,并通过扫描电子显微镜(SEM)、傅里叶红外光谱仪(FT-IR)、X射线衍射仪(XRD)和X射线光电子能谱仪(XPS)对其进行表征。采用碳基复合材料修饰玻碳电极构建了Hg(II)的电化学敏感界面,通过方波阳极溶出伏安法(SWASV)对Hg(II)进行了选择性测定,取得的结果如下:(1)最优化条件下煅烧600℃材料的灵敏度和最低检测限(LOD)分别达到了27.945μA/μM和0.0145μM(S/N=3);(2)0.5μM的重金属离子Cd^(2+)、Zn^(2+)、Pb^(2+)、Cu^(2+)对检测Hg^(2+)的干扰均在可控范围内;(3)实际水样中Hg^(2+)的检测达到了92%-93%的回收率。研究拓展了染料化工废水铁基混凝污泥在电化学检测方向的资源化利用。

Demineralised Lignite Fly Ash for the Removal of Zn(II) Ions from Aqueous Solution

Among the various possibilities of limiting the disposal of fly ashes (lignite), their reutilization as adsorbent materials is worthy of consideration. To this end, proper ashes beneficiation techniques can be put into practice. The adsorption of toxic compounds from industrial wastewater is an effective method for both treating these effluents and recycling lignite fly ash. The aim of this paper is to give a contribution for understanding the relationships among beneficiation treatments, adsorbent properties and adsorption mechanism and efficiency. In this context, the lignite fly ash was demineralised using concentrated HCl and HF (FA-DEM) and was used as adsorbent for Zn(II) ions from aqueous solutions. Batch experiments were carried out under various adsorbent dosages, pH, contact time and different metal ion concentrations. For FA-DEM, the 57.7% removal of Zn(II) ion was achieved under the optimum conditions of adsorbent dosages of 4 g/L, pH at 6, temperature at 303 K and the contact time of 1.15 h. The adsorption of Zn(II) ions onto FA-DEM followed the pseudo second order kinetics. The Langmuir isotherm model best represented the equilibrium data.

Preparation, Characterization, and Application of Manganese Oxide Coated Zeolite as Adsorbent for Removal of Copper(II) Ions from Seawater

The present study is aimed to examine the adsorption characteristics of Cu(II) by using the novel cellulose acetate composite and to apply it for the removal of Cu(II) from real wastewater samples. In order to achieve this objective, ethylenediamine, diethylenetriamine, triethylenetetramine and te-traethylenepentanene were used for immobilization of grafted cellulose acetate-nanoscale manganese dioxide. Cellulose was extracted from mangrove species Avicennia marina and converted to cellulose acetate then it was formed composite with nano-manganese dioxide via precipitation of nano-manganese dioxide on it. The composite was grafted with acrylamide monomer before immobilization. The synthesized compounds were used for adsorption of Cu(II) and characterized by FT-IR, TGA and SEM. The adsorption characteristics of synthesized sorbents were optimized. Langmuir and Freundlich models were used to establish sorption equilibria. The analytical applications of these modified materials were applied successfully for the removal of Cu(II).

Application of 3A Zeolite Prepared from Venezuelan Kaolin for Removal of Pb (II) from Wastewater and Its Determination by Flame Atomic Absorption Spectrometry

This work consists in the use of a 3A zeolite (K-LTA) obtained by a process of exchange of sodium for potassium (4A zeolite), synthesized from Venezuelan kaolin for the removal of Pb (II) ions from aqueous solutions by batch process mode in order to consider its application in treating industrial wastewaters. The 3A zeolite was characterized for X-ray powder diffraction (XRD), Fourier Transform infrared spectroscopy (FTIR) and scanning electron microscopy and energy dispersive X-ray microanalysis (SEM-EDX). The metal concentration in the equilibrium Ce (mg·L-1) after adsorption with 3A zeolite was analyzed using flame atomic absorption spectrometry (FAAS). The influences of the solution pH, contact time, metal initial concentration and adsorbent dosage have been studied. The retention of metal occurring at pH values around 6.5 and the adsorption equilibrium was obtained at 60 min. The equilibrium process was well described by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models. The Langmuir parameters qm (mg·g-1) and b (L·mg-1) (which are related to the sorption capacity and constant of sorption energy) obtained were 14.64 and 5.42 respectively. The Pb (II) experimental uptake was about 14.56 mg·g-1, a little smaller than the theoretical one given by Langmuir isotherm model. The regression parameters and correlation coefficients (R) indicate that the adsorption data for Pb (II) removal fit better the Langmuir isotherm model. Moreover, 0 1/n 1 (1/n is 0.13), indicating that adsorption of metal ions on the zeolite, is a favorable physical process. The application of removing of the metal lead from real samples was examined by industrial wastewater samples. For all samples, the percentage of recovery was found with accuracy of more than 98%. The present work suggests 3A zeolite used as a sorbent material with relatively low cost, obtained from Venezuelan raw material;it is a candidate for removal lead ion and probably other cationic heavy metal species from wastewater.

Some Hybrid Systems of Chiral Schiff Base Zn(II) Complexes and Photochromic Spiropyrans for Environmental Ion Sensing

This is a review article including our recent results and some previous photo functional hybrid system having potential applications for environmental ion sensing. We have prepared several new and known chiral Schiff base Zn(II) complexes and measured (and also calculated) absorption and fluorescence spectra for sole complexes. After assembling hybrid systems with 1,3,3-trime- thylindolino-6’-nitrobenzopyrylospiran (SP) in methanol solutions, we measured spectral changes before and after alternate irradiation of UV and visible light. Intensity of fluorescence spectra for pale yellow Zn(II) complexes (λem = 450 nm, λex = 270 and 360 nm) was quenched by colorless SP (λem = 533 nm, λex = 612 nm). After UV light irradiation to form purple merocyanine (MC), photoisomerization resulted in changes of the intensity of absorption spectra as well as fluorescence spectra. Thus the hybrid systems could successfully act as molecular logic circuit by input (excitation by light) and output (intensity of fluorescence peaks). Moreover, we investigated concentration dependence of doped Zn(II) and Cu(II) ions to confirm quenching of intensity of fluorescence peaks by Zn(II) and Cu(II) MC complexes for metal ion sensing in solutions.

Bioremediation of Lead(II) from Polluted Wastewaters Employing Sulphuric Acid Treated Maize Tassel Biomass

The ability to modify a waste by-product precursor, maize tassel biomass using sulfuric acid as the activating agent with specific focus on Lead(II) ion from water has been proposed. The treating of maize tassel using sulphuric acid is believed to enhance sorption capacity of Lead(II) ions. For this, batch adsorption mode was adopted for which the effects of initial pH, adsorbent dosage, contact time and initial concentration were investigated. Consequently, it was found that the adsorbent capacity depends on pH;since it increases up to 4.5 and then decreases. The highest percentage of Lead(II) ion removal was achieved in the adsorbent dosage of 1.2 g and at an initial concentration of 10 mg/L metal ion. In an attempt to determine the capacity and rate of Lead(II) removal, isotherm and kinetic data were modeled using appropriate equations. To this end, the adsorption data fitted best into the Langmuir model with an R2 (0.9997) while kinetically the Lead(II) adsorption followed the pseudo-second-order model. Furthermore, as a way to address issues related to sustainability, maize tassel is recommended since the process is considered to be a dual solution for environmental cleaning. From one side, it represents a better way to dispose the maize tassel which has no use after fertilization and on the other hand it is an economic source of carbonaceous materials.

The Uptake of Copper(II) Ions by Chelating Schiff Base Derived from 4-Aminoantipyrine and 2-Methoxybenzaldehyde

The Schiff base, 4-[(2-methoxybenzylidene)amino]-1,5-dimethyl-2-phenyl-1H-pyrizol-3(2H)-one (SB), was used for the first time to adsorb copper(II) ions in aqueous solution. Various parameters such as initial pH, agitation period and different initial concentration of copper(II) ions which influenced the adsorption capacity were investigated. The equilibrium adsorption data for copper(II) ions were fitted to Langmuir, Freundlich and Dubinin-Radushkevish isotherm models. The maximum monolayer adsorption capacity of SB as obtained from Langmuir isotherm was 5.64 mg/g. Kinetic data correlated well with the pseudo second-order kinetic model indicating that chemical adsorption was the rate limiting step.

STUDIES ON THE PROPERTIES OF SCHIFF BASE TYPE ARYLMERCURY COMPOUNDS.II ^(199)Hg NMR SPECTRA OF MERCURATED DERIVATIVES OF SUBSTITUTED BENZYLIDENEANILINES

^(199)Hg NHR spectra of 18 Schiff base type arylmercury compounds have been studied.It was further confirmed that in the molecule of XC_6H_4CH=NC_6H_3-2-HgC1-4-CH_3 there exists an intramolecular N→Hg coordination via a four-membered ring.For the series of XC_6H_4CH=NC_6H_3-2-HgCl-4-CH_3(X is a para-or mera-substituent),there is a good linear correlation between δ^(199)Hg and Hammett's o constants.The influence of substituents of C-pheny1 ring on the δ ^(199)Hg can be explained in terms of the intramolecular N→Hg coordination.

城市污水厂污泥改性物对Hg(Ⅱ)吸附的研究

以城市污水处理厂活性污泥为原料,制取干污泥,并将其和化学改性污泥作为吸附剂,对含Hg(Ⅱ)离子的废水进行了吸附试验研究。考察了溶液pH值、吸附剂用量和Hg(Ⅱ)离子的初始浓度对去除率的影响。结果表明,干污泥及其化学改性污泥吸附剂对Hg(Ⅱ)离子的吸附符合Lagergren一级动力学方程。在试验条件下,化学改性污泥的相对吸附量高于干污泥,因此,活性污泥经过化学改性后能够提高对Hg(Ⅱ)离子的吸附能力。用0.1mol/LHNO3溶液进行超声解吸附,Hg(Ⅱ)离子的回收率可达70%左右。利用这种吸附剂可以有效地去除工业废水中的Hg(Ⅱ)离子。