Effective detoxification of hexavalent chromium using sulfate-crosslinked chitosan

2014 ◽  
Vol 70 (12) ◽  
pp. 2047-2055 ◽  
Author(s):  
Shashikant Kahu ◽  
D. Saravanan ◽  
Ravin Jugade
Keyword(s):  
Adsorption Capacity ◽  
Hexavalent Chromium ◽  
Adsorption Efficiency ◽  
X Ray Diffraction ◽  
Column Studies ◽  
X Ray ◽  
Enthalpy Changes ◽  
Rate Kinetics ◽  
Pseudo Second Order ◽  
Crosslinked Chitosan

A sulfate-crosslinked chitosan (SCC) was prepared for effective detoxification of hexavalent chromium (Cr(VI)) from effluents. SCC was characterized using Fourier transform infrared, X-ray diffraction, scanning electron microscopy and energy dispersive X-ray studies. The maximum adsorption of Cr(VI) was observed at pH 6.0 with adsorption capacity of 157 mg/g in accordance with the Langmuir adsorption isotherm model. The adsorption process was found to follow the pseudo-second-order rate kinetics. From the study of various thermodynamic parameters (Gibbs energy, entropy and enthalpy changes), the adsorption capacity was found to decrease with increase in temperature. Column studies were carried out to obtain a breakthrough point of the adsorbent. The adsorbent was regenerated using sodium hydroxide with no change in the adsorption efficiency for up to 10 cycles. Effect of diverse ions on adsorption efficiency was studied and SCC was applied for Cr(VI) removal in synthetic effluents.

scholarly journals Sulphate-Crosslinked Chitosan as an Adsorbent for the Removal of Congo Red Dye From Aqueous Solution

2018 ◽  
Vol 11 ◽  
pp. 117862211881168 ◽  
Author(s):  
Christine Jeyaseelan ◽  
Nisha Chaudhary ◽  
Ravin Jugade
Keyword(s):  
Adsorption Capacity ◽  
Congo Red ◽  
Water Bodies ◽  
X Ray ◽  
Modified Chitosan ◽  
Freundlich Adsorption Isotherm ◽  
Pseudo Second Order ◽  
Crosslinked Chitosan ◽  
Wastewater Samples ◽  
Red Dye

Dyes are a major cause of concern nowadays as large quantities are being released into water bodies causing pollution. In this article, modified chitosan (sulphate crosslinked) has been studied for the removal of Congo red (a benzidine-based anionic diazo dye) which is a toxic dye introduced into water bodies from textile industries. Sulphate-crosslinked chitosan (SCC) was prepared in the laboratory and the characterization of SCC was done by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). Various parameters such as pH, contact time, adsorbent dosage, and concentration of adsorbent were optimized. The adsorption capacity was determined at pH 3.0, at which the percentage recovery was about 90% and followed Freundlich adsorption isotherm with an adsorption capacity of 91.8 mg/g. The adsorption followed pseudo-second-order kinetics. Various thermodynamic parameters were also determined for the change in adsorption with temperature. The SCC was regenerated with NaOH and showed good recycling capacity. The modified chitosan was applied for the removal of Congo red from industrial wastewater samples (spiked).

scholarly journals Fe-TiO2/AC and Co-TiO2/AC Composites: Novel Photocatalysts Prepared from Waste Streams for the Efficient Removal and Photocatalytic Degradation of Cibacron Yellow F-4G Dye

Catalysts ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1137
Author(s):  
Roberto Machado Garcia ◽  
Robert Carleer ◽  
Maria Arada Pérez ◽  
Jeamichel Puente Torres ◽  
Ying Gu ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Adsorption Capacity ◽  
Dye Adsorption ◽  
X Ray Diffraction ◽  
Visible Radiation ◽  
X Ray ◽  
Peanut Hulls ◽  
Pseudo Second Order ◽  
X Ray Absorption ◽  
Degradation Effect

Fe-TiO2/AC and Co-TiO2/AC composites were prepared from activated carbon (AC) derived from residues of peanut hulls and TiO2 photocatalyst, electrochemically prepared from titanium scrap, and doped with Fe and Co, respectively. The adsorption capacity and photocatalytic activity of the Fe-TiO2/AC and Co-TiO2/AC composites were studied for removing and degrading Cibacron Yellow F-4G (CYF-4G) from wastewater. Doped ACs were characterized by thermogravimetry (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), a new X-ray absorption technique (XRA), and elemental analysis (EA). Interesting relationships were found between SEM, XRA, and TGA data and the doped amount of catalyst on ACs. Optimal dye adsorption was found at a pH of 2.0. The CYF-4G adsorption kinetics are followed according to the pseudo-second order model. The experimental data revealed that the Langmuir model fits better than the Freundlich and Temkin models. A decrease in adsorption capacity was observed when the catalyst dope percentage increased. A removal and degradation efficiency of the dye close to 100% was achieved around 120 min. A synergistic adsorption and photocatalytic degradation effect of the Fe-TiO2/AC and Co-TiO2/AC composites could be observed when adsorption experiments were conducted under simulated visible radiation.

Adsorption Mechanism of Rectorite Modified by Lithium

2014 ◽  
Vol 919-921 ◽  
pp. 2017-2021
Author(s):  
Yin An Ming ◽  
Ying Ru Wang ◽  
Zheng Liu ◽  
Fu Rong Zhou
Keyword(s):  
Methylene Blue ◽  
Adsorption Capacity ◽  
Adsorption Mechanism ◽  
Interlayer Spacing ◽  
Blue Dye ◽  
Adsorption Efficiency ◽  
X Ray Diffraction ◽  
X Ray ◽  
Index Measurement ◽  
Infrared Spectrophotometer

In this paper, the mechanism that lithium-modified rectorite (Rec-Li) and raw rectorite adsorbed methylene blue dye in wastewater was investigated, and the adsorption properties of the two adsorbents were also compared. The results showed that the static saturated adsorption capacity of raw rectorite was 77.75mg/g, however, the capacity of lithium-modified rectorite was up to 189.62mg/g, the adsorption efficiency was increased by 144%. Therefore, the adsorption capacity of Rec-Li to methylene blue was much higher than raw rectorite. The Rec-Li and raw rectorite were characterized respectively by means of fourier transform infrared spectrophotometer (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM) and colloid index measurement. The analysis indicated that, after modification by lithium, the colloid index was changed from 12mL/3g to 198mL/3g and the interlayer spacing was changed from 0.01~0.1μm to 1~1.5μm. With the increasing of the colloid index, the dispersion effect of adsorbent in wastewater and the contact area between adsorbent and pollutants were improved. And the increase of interlayer spacing was conducive to pollutants entering the hole and so that the adsorption capacity of Rec-Li was increased significantly.

scholarly journals Synthesis, characterization and adsorption studies of an acrylic acid-grafted sodium alginate-based TiO2 hydrogel nanocomposite

2017 ◽  
Vol 36 (1-2) ◽  
pp. 458-477 ◽  
Author(s):  
Sourbh Thakur ◽  
Omotayo Arotiba
Keyword(s):  
Acrylic Acid ◽  
Adsorption Capacity ◽  
Sodium Alginate ◽  
Methyl Violet ◽  
Maximum Adsorption Capacity ◽  
Nanocomposite Hydrogel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pseudo Second Order ◽  
Hydrogel Nanocomposite

Hydrogel nanocomposites were synthesized by solution polymerization of acrylic acid in the presence of sodium alginate biopolymer and TiO2 nanoparticle. TiO2 nanoparticle and N, N-methylene-bis-acrylamide was used as an inorganic and organic crosslinker, respectively. The structure and morphology of the nanocomposites were investigated using X-Ray Diffraction (XRD), Fourier Transform Infra-Red Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Brunauer-Emmett-Teller (BET) and thermogravimetric analysis techniques. The nanocomposites hydrogel was used for the adsorption of methyl violet dye from water. The influence of TiO2 nanoparticle, sodium alginate content and grafting on adsorption were studied. The results showed that a pseudo-second-order adsorption kinetic was predominant in the adsorption of methyl violet onto the nanocomposite hydrogel. The experimental equilibrated adsorption capacity of the nanocomposite hydrogel agrees with Langmuir isotherm. Maximum adsorption capacity of 1156.61 mg g−1 and adsorption efficiency of 99.6% towards methyl violet were obtained for the hydrogel nanocomposite.

Tamanrasset’s Clay Characterization and Use as Low Cost, Ecofriendly and Sustainable Material for Water Treatment: Progress and Challenge in Copper Cu (II)

2021 ◽  
Vol 406 ◽  
pp. 457-472
Author(s):  
Aicha Kourim ◽  
Moulay Abderrahmane Malouki ◽  
Aicha Ziouche ◽  
Mouna Boulahbal ◽  
Madjda Mokhtari
Keyword(s):  
Adsorption Capacity ◽  
Metal Ion ◽  
Low Cost ◽  
Ion Concentration ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pseudo Second Order ◽  
Equilibrium Process

In this study, the adsorption of copper Cu (II) from aqueous solution, on Tamanrasset’s clay which is low cost adsorbent, was studied using batch experiments. The adsorption study includes both equilibrium adsorption isotherms and kinetics. The characterization of the adsorbent necessitated several methods such as X-Ray Diffraction, Scanning Electron Microscopy coupled with Energy Dispersive X-ray, BET for specific surface area determination, Fourier transform infrared spectroscopy and thermogravimetric analysis. Indeed, various parameters were investigated such as contact time, initial metal ion concentration, mass of solid, pH of the solution and temperature. The adsorption process as batch study was investigated under the previews experimental parameters. The results revealed that the adsorption capacity of Cu2+ is maximized at naturel pH of metal 5.5. Removal of copper by the clay of Tamanrasset (kaolinite) achieved equilibrium within 50 minutes; the results obtained were found to be fitted by the pseudo-second order kinetics model. The equilibrium process was well described by the Langmuir model and the maximum adsorption capacity was found to be 26.59 mg/g.

Adsorption studies of Cu(II) onto biopolymer chitosan and its nanocomposite 5%bentonite/chitosan

2016 ◽  
Vol 73 (9) ◽  
pp. 2199-2210 ◽  
Author(s):  
Hamou Moussout ◽  
Hammou Ahlafi ◽  
Mustapha Aazza ◽  
Omar Zegaoui ◽  
Charaf El Akili
Keyword(s):  
Adsorption Capacity ◽  
Active Sites ◽  
Batch Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Monolayer Adsorption ◽  
Adsorption Processes ◽  
Pseudo Second Order ◽  
Nanocomposite Adsorbent ◽  
Kinetics Of

Chitosan (CS) and nanocomposite 5%bentonite/chitosan (5%Bt/CS) prepared from the natural biopolymer CS were tested to remove Cu(II) ions using a batch adsorption experiment at various temperatures (25, 35 and 45°C). X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis/differential thermal analysis (TGA/DTA) were used in CS and the nanocomposite characterisation. This confirmed the exfoliation of bentonite (Bt) to form the nanocomposite. The adsorption kinetics of copper on both solids was found to follow a pseudo-second-order law at each studied temperature. The Cu(II) adsorption capacity increased as the temperature increased from 25 to 45°C for nanocomposite adsorbent but slightly increased for CS. The data were confronted to the nonlinear Langmuir, Freundlich and Redlich–Peterson models. It was found that the experimental data fitted very well the Langmuir isotherm over the whole temperature and concentration ranges. The maximum monolayer adsorption capacity for the Cu(II) was 404–422 mg/g for CS and 282–337 mg/g for 5%Bt/CS at 25–45°C. The thermodynamic study showed that the adsorption process was spontaneous and endothermic. The complexation of Cu(II) with NH2 and C = O groups as active sites was found to be the main mechanism in the adsorption processes.

scholarly journals Kinetics, isotherm and thermodynamic studies of S2− adsorption by (SBA-15)-Hg (II)

2021 ◽  
Author(s):  
Xiao-Dong Li ◽  
Qing-Zhou Zhai
Keyword(s):  
Nitrogen Adsorption ◽  
Order Equation ◽  
Adsorption Properties ◽  
Adsorption Efficiency ◽  
X Ray Diffraction ◽  
Santa Barbara ◽  
Isothermal Adsorption ◽  
X Ray ◽  
Pseudo Second Order ◽  
Adsorption Desorption

Abstract The nano-mesoporous material SBA (Santa Barbara Amorphous)-15 was synthesized using the hydrothermal method. Hg2+ was adsorbed by SBA-15 and then the S2− in the aqueous phase by (SBA-15)-Hg(II), with the hope that materials with better S2− adsorption properties can be obtained. The relevant materials were characterized by X-ray diffraction, scanning electron microscopy, 77 K nitrogen adsorption-desorption, and related product characteristics were determined. In this work, the adsorption conditions of S2− onto (SBA-15)-Hg(II) were optimized. Adsorption efficiency reached about 92% and the adsorption capacity 55.02 mg/g. Studies of the system's adsorption kinetics showed that the pseudo-second-order equation applies. The thermodynamic results indicated that ΔG0 < 0, ΔH0 = −28.56 kJ/mol, ΔS0 = −81.136 J/(mol·K), and that adsorption is exothermic, enthalpy decreases and the reaction is spontaneous. This accords with Freundlich isothermal adsorption equation.

scholarly journals Removal of tetracycline antibiotics from aqueous solutions using easily regenerable pumice: batch and column study

2018 ◽  
Vol 53 (3) ◽  
pp. 143-155 ◽  
Author(s):  
Jianbo Lu ◽  
Kai Xu ◽  
Wanlu Li ◽  
Dongmei Hao ◽  
Lingmin Qiao
Keyword(s):  
Aqueous Solutions ◽  
X Ray Diffraction ◽  
Column Studies ◽  
X Ray ◽  
Adsorption Mechanisms ◽  
Edta Solution ◽  
Pseudo Second Order ◽  
Rate Controlling Step ◽  
Langmuir And Freundlich Models ◽  
Inner Sphere Complexes

Abstract Mineral pumice as an adsorbent was explored for tetracycline (TC) removal from water. Pumice was characterized by X-ray diffraction, X-ray fluorescence and Fourier transform infrared spectroscopy. Batch and column studies were conducted to investigate the adsorbability of pumice towards TC. Results showed that the TC adsorption amount declined as the pH increased from 3 to 9 and was strongly dependent on ionic strength. Adsorption kinetic data fitted to the pseudo-first-order, pseudo-second-order and Elovich model very well (R2 > 0.9). Intraparticle diffusion was the main rate controlling step during TC adsorption. The Langmuir and Freundlich models were utilized to simulate isotherm data (10–30°C). The obtained Langmuir uptake amount (20°C) was 3.345 mg/g. Thermodynamic analyses showed that the TC uptake amount increased with the temperature rising, suggesting its endothermic nature. At pH 6 and 8, both Pb2+ and Cu2+ significantly promoted the TC removal (>25%) via ion bridging action. Adsorption mechanisms mainly involved physisorption (Van der Waals & electrostatic forces) and chemisorption via the formation of inner-sphere complexes. Column tests showed that the exhausted column could be effectively regenerated using alkaline EDTA solution. Current results suggest that pumice is a promising adsorbent for TC removal from aqueous solutions.

scholarly journals Zeolite NaP1 Functionalization for the Sorption of Metal Complexes with Biodegradable N-(1,2-dicarboxyethyl)-D,L-aspartic Acid

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2518
Author(s):  
Dorota Kołodyńska ◽  
Yongming Ju ◽  
Małgorzata Franus ◽  
Wojciech Franus
Keyword(s):  
Experimental Data ◽  
Aspartic Acid ◽  
Ph Value ◽  
Complexing Agents ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Modified Zeolite ◽  
X Ray ◽  
Slow Release Fertilizers ◽  
Pseudo Second Order

The possibility of application of chitosan-modified zeolite as sorbent for Cu(II), Zn(II), Mn(II), and Fe(III) ions and their mixtures in the presence of N-(1,2-dicarboxyethyl)-D,L-aspartic acid, IDHA) under different experimental conditions were investigated. Chitosan-modified zeolite belongs to the group of biodegradable complexing agents used in fertilizer production. NaP1CS as a carrier forms a barrier to the spontaneous release of the fertilizer into soil. The obtained materials were characterized by Fourier transform infrared spectroscopy (FTIR); surface area determination (ASAP); scanning electron microscopy (SEM-EDS); X-ray fluorescence (XRF); X-ray diffraction (XRD); and carbon, hydrogen, and nitrogen (CHN), as well as thermogravimetric (TGA) methods. The concentrations of Cu(II), Zn(II), Mn(II), and Fe(III) complexes with IDHA varied from 5–20 mg/dm3 for Cu(II), 10–40 mg/dm3 for Fe(III), 20–80 mg/dm3 for Mn(II), and 10–40 mg/dm3 for Zn(II), respectively; pH value (3–6), time (1–120 min), and temperature (293–333 K) on the sorption efficiency were tested. The Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin adsorption models were applied to describe experimental data. The pH 5 proved to be appropriate for adsorption. The pseudo-second order and Langmuir models were consistent with the experimental data. The thermodynamic parameters indicate that adsorption is spontaneous and endothermic. The highest desorption percentage was achieved using the HCl solution, therefore, proving that method can be used to design slow-release fertilizers.

Efficient adsorption of chlorpyrifos onto modified activated carbon by gamma irradiation; a plausible adsorption mechanism

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohamed S. Yahia ◽  
Ahmed S. Elzaref ◽  
Magdy B. Awad ◽  
Ahmed M. Tony ◽  
Ahmed S. Elfeky
Keyword(s):  
Gamma Irradiation ◽  
Area Measurement ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Order ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Pseudo First Order ◽  
Kinetics Of

Abstract Commercial Granulated Active Carbon (GAC) has been modified using 10 Gy dose Gamma irradiation (GAC10 Gy) for increasing its ability of air purification. Both, the raw and treated samples were applied for removing Chlorpyrifos pesticide (CPF) from ambient midair. Physicochemical properties of the two materials were characterized by Fourier Transform Infrared (FT-IR) and Raman spectroscopy. The phase formation and microstructure were monitored using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), supported with Energy-Dispersive X-ray (EDX). The Surface area measurement was detected using BET particle size prosometry. Obtained outcomes showed that, the maximum adsorption capacity, given by Langmuir equations, was greatly increased from 172.712 to 272.480 mg/g for GAC and GAC10 Gy, respectively, with high selectivity. The overall removal efficiency of GAC10 Gy was notably comparable to that of the original GAC-sorbent. The present study indicated that, gamma irradiation could be a promising technique for treating GAC and turned it more active in eliminating the pesticides pollutants from surrounding air. The data of equilibrium has been analyzed by Langmuir and Freundlich models, that were considerably better suited for the investigated materials than other models. The process kinetics of CPF adsorbed onto both tested carbon versions were found to obey the pseudo first order at all concentrations with an exception at 70 mg/l using GAC, where, the spontaneous exothermic adsorption of Chlorpyrifos is a strong function for the pseudo-first order (PFO) and pseudo second order (PSO) kinetics.

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