Sorption Isotherms of Heavy Metal Ions onto Semi-Interpenetrating Polymer Network Cryogels Based on Polyacrylamide and Anionically Modified Potato Starch

Application of ANN to the Sorption Equilibrium Modelling of Heavy Metal Ions on Clinoptilolite The latest achievements in the field of mathematical modelling include the application of artificial neural networks (ANN). A growing interest in the ANN is confirmed by the number of publications devoted to the applicability of ANN in chemical, process and environmental engineering. A recent dynamic development of ANN provided an efficient and universal tool that is used to solve many tasks, including modelling, approximation and identification of objects. The initial step of applying the network to a given process consists in the determination of weights of the proposed neural network structure. This is performed on the basis of training data. A network that is properly trained allows correct information to be obtained on the basis of other data which have not been used in the network training. In most cases the network training is performed on the basis of a known mathematical model. However, the training of a network can be also performed using experimental data. In this paper, the sorption isotherms were predicted by means of a multilayer perceptron (MLP). Calculations were made using a training program written in Matlab, which took advantage of the Lavenberg-Marquardt procedure. In the last decade a growing interest is observed in inexpensive and very cheap adsorbents to remove heavy metal ions. Clinoptilolite is the mineral sorbent extracted in Poland used to remove heavy metal ions from diluted solutions. Equilibrium experiments were carried out to estimate sorptivity of a clinoptilolite and its selectivity towards Cu(II), Zn(II) and Ni(II) ions for multicomponent solution. Calculations with the use of MLP enabled description of sorption isotherms for one, two and three ions which were present at the same time in the solution. The network also enabled an analysis of sorption of the single ion, taking into account the effect of its concentration.

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Absorbed Pb2+ and Cd2+ Ions in Water by Cross-Linked Starch Xanthate

International Journal of Polymer Science ◽

10.1155/2017/6470306 ◽

2017 ◽

Vol 2017 ◽

pp. 1-9 ◽

Cited By ~ 5

Author(s):

Kai Feng ◽

Guohua Wen

Keyword(s):

Heavy Metal ◽

Metal Ions ◽

Heavy Metal Ions ◽

Adsorption Mechanism ◽

Potato Starch ◽

Sodium Acrylate ◽

X Ray Diffraction ◽

X Ray ◽

Concentration Of Ions ◽

Cross Linker

A cross-linked starch xanthate was prepared by graft copolymerization of acrylamide and sodium acrylate onto starch xanthate using potassium persulfate and sodium hydrogen sulfite initiating system and N,N′-methylenebisacrylamide as a cross-linker. As this kind of cross-linked potato starch xanthate can effectively absorb heavy metal ions, it was dispersed in aqueous solutions of divalent heavy metal ions (Pb2+ and Cd2+) to investigate their absorbency by the polymer. Factors that can influence absorbency were investigated, such as the ratio of matrix to monomers, the amount of initiator and cross-linker, pH, and the concentration of metal ions. Results were reached and conclusion was drawn that the best synthetic conditions for the polymer adsorbing Pb2+ and Cd2+ were as follows: the quality ratio of matrix to monomers was 1 : 12 and 1 : 11, the amount of initiator was 2.4% and 3.2% of matrix, and the amount of cross-linker was 12 mg and 13 mg. When the initial concentration of ions was 10 mg/L, the highest quantities of adsorption of Pb2+ and Cd2+ were 47.11 mg/g and 36.55 mg/g. Adsorption mechanism was discussed by using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) test, and adsorption kinetic simulation.

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Sorption performance of cysteine-modified bentonite in heavy metals uptake

Journal of the Serbian Chemical Society ◽

10.2298/jsc0907833f ◽

2009 ◽

Vol 74 (7) ◽

pp. 833-843 ◽

Cited By ~ 12

Author(s):

Hossein Faghihian ◽

Massoud Nejati-Yazdinejad

Keyword(s):

Heavy Metal ◽

Metal Ions ◽

Metal Binding ◽

Heavy Metal Ions ◽

Sorption Isotherms ◽

Local Clay ◽

Lead And Cadmium ◽

Sorption Parameters ◽

Thiol Ligand ◽

Heavy Metals Uptake

A local clay, bentonite (N-Ben), was modified by the biologically-based ligand, cysteine (Cys), through a simple sorption technique. The modified sorbent (Cys-Ben) demonstrated affinity for soft and moderately soft heavy metal ions (HMI), such as Cd(II) and Pb(II), probably as a result of the soft basic character of the thiol ligand side chains. The resulting modified system was effective for metal binding with capacities of 0.503 and 0.525 mmol g-1, for Pb(II) and Cd(II), respectively. Comparative batch experiments were performed for removing lead and cadmium from aqueous solutions. The sorption parameters were derived from a Langmuir fit to the sorption isotherms of the studied ions. The study showed that the sorption capacity of Cys-Ben was higher than that of N-Ben for these ions. The effect of pH was examined over the range 2.0-6.0. The sorption capacities of Cys-Ben showed that this modified clay is a good sorbent for the examined heavy metal ions.

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The Studies of Adsorption of Heavy Metal Ions of Lead and Copper by Distillers' Grains

Materials Science Forum ◽

10.4028/www.scientific.net/msf.695.77 ◽

2011 ◽

Vol 695 ◽

pp. 77-80 ◽

Cited By ~ 1

Author(s):

Juan Feng ◽

Xiao Yan Lin ◽

Xue Gang Luo ◽

Jia Quan Rao ◽

Chun Yan Zhang

Keyword(s):

Heavy Metal ◽

Metal Ions ◽

Heavy Metal Ions ◽

Removal Rate ◽

Structural Characteristics ◽

Sorption Isotherms ◽

Distillers Grains ◽

Sorption Data ◽

Adsorption Behaviors ◽

Heavy Metal Wastewater

The absorption of Cu2+ and Pb2+ in the heavy metal wastewater by distillers' grains can not only solve the problem of environmental pollution, but also change distillers' grains waste into resource. Structural characteristics of distillers' grains and its adsorption behaviors for the heavy metal ions of Cu2+ and Pb2+ were studied and effects of various parameters including pH, temperature, distillers' grains dose, initial Cu2+ and Pb2+ concentration and absorbed time on the absorption of Pb2+ and Cu2+ were evaluated. Sorption isotherms were also investigated. Results show that the rough surface, loose internal structure and hydroxy and amide groups of the distillers' grains are beneficial to the adsorption of Cu2+ and Pb2+ in the wastewater. The removal rate of the distillers' grains for Pb2+ (20.00 mg L−1) and Cu2+ (20.00 mg L−1) are, respectively, 96.72% and 87.70% under optimized conditions. The equilibrium sorption data are well demonstrated by Langmuir model.

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Prospects for the Production and Application of New Zeolite-Like Sorption Materials for Waste Water Treatment in Railway Enterprises

Ecology and Industry of Russia ◽

10.18412/1816-0395-2020-6-4-9 ◽

2020 ◽

Vol 24 (6) ◽

pp. 4-9

Author(s):

М.V. Obuzdina ◽

E.A. Rush

Keyword(s):

Heavy Metal ◽

Wastewater Treatment ◽

Metal Ions ◽

Heavy Metal Ions ◽

Raw Materials ◽

Waste Water Treatment ◽

Polymer Network ◽

Waste Products ◽

Main Component ◽

Sulfur Containing

The article presents the results of researches of zeolite modification in order to create sorbents for wastewater treatment from heavy metal ions. Zeolitive tuffs of deposit of the Zabaikalye Territory are considered as raw materials. It is proposed to modify zeolites with highly organosilicon compounds hexamethyldisilazane [(CH3)3Si]2NH and tetraethoxysilane (С2H5O)4Si, which leads to hydrophobization of the surface and an increase in adsorption capacity. A method for modifying the structure of natural zeolite with a sulfur-containing polymer obtained from waste products of epichlorohydrin, the main component of which is 1,2,3-trichloropropane, is described in more detail. A sulfur-containing polymer network is formed by using sulfur dissolution at room temperature in the monoethanolamine – hydrazine hydrate system and condensation with 1,2,3-trichloropropane. The result of applying a sulfur-containing polymer network is not only hydrophobization of the zeolite surface, but also the appearance of sulfur atoms in its composition, which increases the selectivity to heavy metal ions. Based on the obtained experimental data, the method of improvement the existing technologies for wastewater treatment at enterprises (railway transport) by introducing a deep post-treatment into the sorption unit scheme is proposed.

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Tough and Self-Healable Nanocomposite Hydrogels for Repeatable Water Treatment

Polymers ◽

10.3390/polym10080880 ◽

2018 ◽

Vol 10 (8) ◽

pp. 880 ◽

Cited By ~ 5

Author(s):

Kunhao Yu ◽

Di Wang ◽

Qiming Wang

Keyword(s):

Heavy Metal ◽

Metal Ions ◽

Heavy Metal Ions ◽

Dye Degradation ◽

Uv Light ◽

Polymer Network ◽

Polymer Chains ◽

Self Healing ◽

Nanocomposite Hydrogel ◽

Water Stream

Nanomaterials with ultrahigh specific surface areas are promising adsorbents for water-pollutants such as dyes and heavy metal ions. However, an ongoing challenge is that the dispersed nanomaterials can easily flow into the water stream and induce secondary pollution. To address this challenge, we employed nanomaterials to bridge hydrogel networks to form a nanocomposite hydrogel as an alternative water-pollutant adsorbent. While most of the existing hydrogels that are used to treat wastewater are weak and non-healable, we present a tough TiO2 nanocomposite hydrogel that can be activated by ultraviolet (UV) light to demonstrate highly efficient self-healing, heavy metal adsorption, and repeatable dye degradation. The high toughness of the nanocomposite hydrogel is induced by the sequential detachment of polymer chains from the nanoparticle crosslinkers to dissipate the stored strain energy within the polymer network. The self-healing behavior is enabled by the UV-assisted rebinding of the reversible bonds between the polymer chains and nanoparticle surfaces. Also, the UV-induced free radicals on the TiO2 nanoparticle can facilitate the binding of heavy metal ions and repeated degradation of dye molecules. We expect this self-healable, photo-responsive, tough hydrogel to open various avenues for resilient and reusable wastewater treatment materials.

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Water purification from heavy metal ions by nano-sized Fe0/kaolinite composites

Reports of the National Academy of Sciences of Ukraine ◽

10.15407/dopovidi2020.11.096 ◽

2020 ◽

pp. 96-103

Author(s):

I.A. Kovalchuk ◽

◽

V.Yu. Tobilko ◽

A.I. Bondarieva ◽

Yu.M. Kholodko ◽

...

Keyword(s):

Heavy Metal ◽

Metal Ions ◽

Heavy Metal Ions ◽

Sorption Isotherms ◽

Active Surface ◽

Toxic Heavy Metal ◽

Physicochemical Features ◽

Sorbent Materials ◽

Effective Sorbent ◽

Sorption Characteristics

We have investigated the physicochemical features of the purification of wastewater that are complex on its content and include a mixture of heavy metal ions (Cu(II), Cd(II), Zn(II), Co(II), Cr(VI)). The phase of a composition and structural-sorption characteristics of synthesized nano-sized Fe0/kaolinite composites were studied. It was found that the obtained materials have much better sorption properties for the extraction of heavy metals from aqueous solutions in comparison with natural kaolinite. Calculations of sorption isotherms according to the Freundlich equation are done. Based on isotherms, the average values of specific sorption per unit of an active surface of the mineral at the content of heavy metal ions in the initial solutions of 300 μmol/dm3 were determined. They range from 0.42 to 17.1 μmol/g for Cr(VI) to Cu(II) ions. It has also been found that similar values for the modified samples are much larger and range from 13.8 to 80.27 μmol/g for ions from Cr(VI) to Cu(II). It is shown that composite sorbents based on nano-sized zero-valent iron and dispersed kaolinite silicate are effective sorbent materials for the purification of water contaminated with toxic heavy metal ions that are commonly found in wastewater of the galvanic and hydrometallurgical industries.

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Adsorption Properties for Superabsorbent of Inverse Suspension Polymerization Poly(acrylate-Co-Acrylamide)

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.239-242.851 ◽

2011 ◽

Vol 239-242 ◽

pp. 851-854 ◽

Cited By ~ 3

Author(s):

Jian Jun Xie ◽

Na Li ◽

Kai Huang ◽

Xin Qiang Han

Keyword(s):

Heavy Metal ◽

Metal Ions ◽

Metal Ion ◽

Heavy Metal Ions ◽

Selective Adsorption ◽

Suspension Polymerization ◽

Polymer Network ◽

Adsorption Properties ◽

Ph Values ◽

Inverse Suspension Polymerization

Superabsorbent polymers are lightly crosslinked, hydrophilic polymer network having many functional groups. The adsorption properties in heavy metal ion solutions using poly(acrylate-co-acrylamide)(PAAM) are investigated. It is found that PAAM has a high uptake to heavy metal ions, and that the adsorption of heavy metal ions is greatly influenced by pH and the initial solution concentrations. The biggest and the smallest amount of adsorption are Cu2+and Cr3+in CuCl2and CrCl3solution, respectively. It was feasible for selective adsorption of the metal ions in the solution onto PAAM hydrogel by controlling the pH values of the mixing solution for CuCl2, FeCl3, CrCl3.Langmiur equatiom can satisfactorily fit for the adsorption of Cu2+while not fit for that of Fe3+and Cr3+.

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