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).

Synthesis of platy potassium magnesium titanate and its application in removal of copper ions from aqueous solution

Platy potassium magnesium titanate (K0.8Mg0.4Ti1.6O4, KMTO) was synthesized by a flux method. The potential application of KMTO in removing copper ions from water pollutants was investigated. The crystal phases of specimens were identified by XRD. The morphology and structural information were characterized by SEM and TEM. The adsorption behavior under different conditions was investigated, including different pH values and different initial copper ion concentrations. The results show that the maximum adsorption capacity of Cu(II) ions is 290.697 mg/g, and almost 99.9% of Cu(II) ions can be removed, which is much higher than that of other sorbents reported. The kinetics of KMTO for the adsorption of Cu(II)ions was studied and the best fit can be obtained by the pseudo-second-order model. Adsorption isothermal data can be well interpreted by the Freundlich equation (R2=0.991). In conclusion, this study highlights that KMTO is a potential material for the efficient removal of heavy metal ions in polluted water. It also opens up a new opportunity for the applications of platy KMTO.

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.

Removal of Copper Ions from Acid Mine Drainage Wastewater Using Ion Exchange Technique: Factorial Design Analysis

A factorial experimental design method was used to examine the “Cu2+” removal from acid mine drainage wastewater by ion exchange technique. Ion Exchange technique is preferred because of reduced sludge generation compared to conventional treatment techniques and better decontamination efficiency from highly diluted solutions. Factorial design of experiments is employed to study the effect of four factors pH (3, 5, and 6), flow rate (5, 10, 15 L/hr), resin bed height (20, 40 and 60 cm) and initial concentration of the metal (100, 150 and 200 mgl-1) at three levels. The efficiency of metal removal was determined after 100 min of treatment. Main effects and interaction effects of the four factors were analyzed using statistical techniques. A regression model was recommended and it was found to fit the experimental data very well. The results were analyzed statistically using the Student’s t-test, analysis of variance, F-test and lack of fit to define most important process variables affecting the percentage “Cu2+” removal. In this study , pH was thus found to be the most important variable.

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.

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.

Deep removal of copper from cobalt sulfate electrolyte by ion-exchange

SP-C was applied for the removal of Cu^2＋ from simulated cobalt sulfate electrolyte containing Co2＋ 50 g/L and Cu2＋ 0.5-2.0 g/L. Experimental conditions included pH of 2-4, temperature of 20-60℃ and contact time of 10-40 min. The investigation demonstrated that SP-C had recommendable efficiency in adsorbing Cu2＋ from the electrolyte with 25- to 100-fold of Co2＋ The optimal adsorption conditions of SP-C were pH of 4, contact time of 30 min and ambient temperature. The study also showed that the loaded resin could be effectively eluted with 2.0 mol/L H2SO4 solution at a contact time of 40 min; the peak concentration of Cu2＋ in the eluate was about 35 g/L. The sorption characteristics of Cu2＋ by SP-C could be described by Langrnuir isotherm and the pseudo second-order kinetic equation. Infrared spectra showed that nitrogen atoms in the functional group coordinated with Cu2＋ to form coordination bands.

Removal of copper from nickel anode electrolyte through ion exchange

An novel method for removal of copper from nickel anodic electrolyte through ion exchange was studied after cupric deoxidization. Orthogonal design experiments show the optimum conditions of deoxidizing cupric into Cu+ in the nickel electrolyte are the reductive agent dosage is 4.5 times as the theoretic dosage and reaction time is 0.5 h at 40 ℃ and pH 2.0. Ion exchange experiments show that the breakthrough capacity(Y) decreases with the increase of the linear flow rate(X): Y=1.559-0.194X+ 0.006 7X2. Breakthrough capacity increases with the increase of the ratio of height to radius(RRH). The higher the initial copper concentration, the less the breakthrough capacity(BC). SO42- and nickel concentration have no obvious change during the process of sorption, so it is not necessary to worry about the loss of nickel during the sorption process. Desorption experiments show that copper desorption from the resin is made perfectly with NaCl solution added with 4% (volume fraction) H2O2 (30%) and more than 100 g/L CuCl2 solution is achieved.

Removal of Some Toxic Ions from Seawater and Wastewater by Sorption onto Natural, Synthetic Hydroxyapatite and Alginate-Hydroxyapatite Composite Nanoparticles: A Comparative Study

The main objective of this paper is to study the removal of Cadmium(II), Lead(II), Chromium(VI), and Mercury(II) ions by sorption onto different natural and synthetic nanoparticles. Special attention has been given to the application of fish bone in nanoform as a useful, inexpensive and eco-friendly alternative material. A comparison between natural hydroxyapatite (fish bone), synthetic hydroxyapatite nanoparticles (HAP) and alginate-hydroxyapatite composite (Alg/Hap) to assess their removal efficiencies to remediate the selected heavy metals has been done. Surface characterization by using different techniques has also been performed to understand the influence of surface characteristics of the adsorbent materials in the removal process. Different parameters (pH, contact time, mass dose and metal ion concentration) have been examined to identify the optimum conditions for remediation of different metals from polluted water. The potential applications of the biosorbents for removal and sorption of these metal ions from seawater and wastewater samples were also investigated and evaluated.

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.

6-(N,N-Dimethylamino)-2-naphthoylacryl Acid:a Highly Selective and Sensitive Fluorescent Sensor of Copper(Ⅱ)

A novel fluorescent probe,6-（N,N-dimethylamino）-2-naphthoylacryl acid（ACADAN） was designed and synthesized as a fluorescent sensor for Cu^2＋ in aqueous media.Significant amplification of fluorescence signals without causing any discernible change of maximum fluorescence emission wavelength（λ max） was observed upon the addition of Cu^2＋.Importantly,ACADAN is capable of recognizing Cu^2＋ selectively in aqueous media in the presence of various biologically relevant metal ions and the prevalent toxic metal ions in the environment with high sensitivity（detection limit was 0.1 μmol/L）.

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.

Adsorption Kinetics of Cupric Ions on Mixture of Modified Corn Stalk and Modified Tomato Waste

The water crisis is an increasingly severe global problem that may be reduced by reusing wastewater after suitable treatment methods. Nowadays, biosorption is one of the main parts of environmental technology which could adsorb heavy metals. This paper describes the adsorption of Copper(II) ions from aqueous solution using a mixture of corn stalk and tomato waste which were oxidized with nitric acid. Kinetic and isotherm studies were carried out by studying the effects of parameters such as concentration dosage, time and pH. It was found that the maximum sorption capacity of the mixture of modified corn stalk and modified tomato waste (qm = 25 mg/g) was higher than the modified corn stalk (qm = 20.8 mg/g). Analysis indicated that pseudo-second-order kinetics controlled the adsorption rate and it has been proposed to correlate the experimental data well.

Cu(II)在对甲苯磺酸铜+DMSO中的电还原

制备了对甲苯磺酸铜并首次用于电化学实验.差示扫描量热和热重曲线测定表明,对甲苯磺酸铜结晶容易脱除全部结晶水,无水盐在空气中不潮解.用循环伏安曲线、计时电流曲线和恒电流电解后的电位-时间曲线研究Cu(Ⅱ)在二甲基亚砜(DMSO)溶液中的电还原.结果表明,Cu(II)电还原为Cu的反应分两步进行,其中第一步是可逆过程.测定了Cu(II)在DMSO溶液中的扩散系数.

响应面法优化铁尾矿砂对铜(II)的吸附条件

以铁尾矿砂作为水体沉积物污染修复覆盖材料,研究了不同pH值、转速下铁尾矿砂对水相中Cu2+去除情况,得出水相pH值在3~5时有利于Cu2+去除率的提高;静态吸附与动态吸附相比有显著差异,转速为180 r/min时,铁尾矿砂对水相中Cu2+去除率最高。使用Box-Behnken设计了响应面试验,研究了水相pH值、温度、Cu2+初始浓度以及铁尾矿砂投加量4个因素对水相中Cu2+去除作用,建立了铁尾矿砂对水中Cu2+去除率的回归模型。其中各因素对响应值的影响次序为:温度>投加量>初始浓度>pH值。模型验证结果预测去除率与试验值偏差仅为0.08%,能够很好预测去除率变化情况。

Cu^2+-catalyzed mechanism in oxygen-pressure acid leaching of artificial sphalerite

The potential autoclave was used to study the catalytic mechanism of Cu^2+during the oxygen pressure leaching process of artificial sphalerite.By studying the potential change of the system at different temperatures and the SEM–EDS difference of the leaching residues,it was found that in the temperature range of 363–423 K,the internal Cu^2+formed a Cu S deposit on the surface of sphalerite,which hindered the leaching reaction,resulting in a zinc leaching rate of only 51.04%.When the temperature exceeds 463 K,the system potential increases steadily.The increase in temperature leads to the dissolution of the CuS,which is beneficial to the circulation catalysis of Cu^2+.At this time,the leaching rate of Zn exceeds 95%.In addition,the leaching kinetics equations at 363–423 and 423–483 K were established.The activation energy of zinc leaching at 363–423 and 423–483 K is 38.66 and 36.25 kJ/mol,respectively,and the leaching process is controlled by surface chemical reactions.

Preparation of Dicarboxyl Cellulose Nanocrystals from Agricultural Wastes by Sequential Periodate-Chlorite Oxidation

Agricultural waste straw is the renewable resource with the highest annual yield in the world.In value-added applications of agricultural waste,dicarboxyl cellulose nanocrystals(DCCs)are prepared from rice,wheat,and corn straw by sequential periodate-chlorite oxidation.In this study,DCCs from rice,wheat,and corn straw were characterized by transmission electron microscopy(TEM),Fourier transform infrared spectrometer,X-ray diffractometer(XRD),and thermal gravimetric analysis(TGA).The carboxyl content of the DCCs was also investigated.XRD results show that the crystallinity index decreased after sequential periodate-chlorite oxidation;however,the cellulose I structure was maintained.TEM results show that rod-shaped DCCs with an average length and width of 287.0 nm and 9.9 nm,respectively,were successfully prepared by sequential periodate-chlorite oxidation.The carboxyl content of the DCCs was around 3.9 mmol/g,and not affected by the type of straw.Experiments to study the removal of copper ions in aqueous medium were performed with the prepared DCCs.The adsorption capacities of copper ions were 131,162,and 144 mg/g for DCCs prepared from rice,wheat,and corn straws,respectively.The results show that DCCs prepared from rice,wheat,and corn straws by sequential periodatechlorite oxidation have potential for the removal of copper ions from aqueous medium.

Synthesis of a crescent aromatic oligothioamide and its high selectivity in recognizing copper(II) ions

Functionalization of shape-persistent aromatic oligoamides still represents a difficult task nowadays. A crescent aromatic oligothioamide was synthesized by simple thionation of the corresponding oligoamide with the Lawesson＇s reagent. The results from UV-vis spectra of the molecule upon metal ion complexation demonstrated its higher selectivity in recognizing Cu2~ ions compared to the oligoamide precursor. The stoichiometry of the complex formed between the thioamide and Cu2＋ was found to be 1：1 with a binding constant of （4.3 ± 0.9） × 104 mol/L.

Identification and Quantification of Intracoordination Water in Insoluble Pectinates Cu²⁺and Pb²⁺

By derivatography in insoluble pectins Cu2+ (РCu2+) and Pb2+ (РPb2+), the presence of “a high-temperature component” (150°C- 165°C) is established. During potentiometric alkalimetric titration of РCu2+ and РPb2+, endpoints are established at рН accordingly 4.87 and 4.95, proving acid properties of PM. Obtained data show the presence of water in the internal sphere of PM. Considering the loss of this water and the known ratio of metal cations and monomers of pectin (L-), the simplest formulas of pectins are established: [Cu(L-)2(H2O)2], [Pb(L-)2(H2O)4].

Study of Adsorption Isotherm Curves of Amino Acids on the Kaolinite

This paper studies the adsorption isotherm curves of four amino acids (glycine, aspartic acid, glutamic acid and lysine) and the effects of existences of different concentrations of Cu(II) on them. Both the adsorption isotherm of the amino acids on the kaolinite and that when the copper ion Cu (II) exists belong to the Langmuir type. The slopes of these adsorption isotherm increase with the increasing concentrations of Cu(II) added. It can be explained in terms of formation of the type(I) ternary surface complexes in these systems. The regular pattern of the effects of copper ion Cu(II) on the adsorption isotherm of amino acids on the kaolinite is identical with that of its effects on the exchange and adsorption percentage E (%)-pH on the kaolinite in the same system.