Preparation and characterization of ZnO/Chitosan nanocomposite for Cs(I) and Sr(II) sorption from aqueous solutions

2021 ◽  
Author(s):  
G. A. Dakroury ◽  
E. A. A. El-Shazly ◽  
H. S. Hassan
Keyword(s):  
Aqueous Solutions ◽  
Sorption From Aqueous Solutions

scholarly journals Preparation and Characterization of the Sulfur-Impregnated Natural Zeolite Clinoptilolite for Hg(II) Removal from Aqueous Solutions

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 217
Author(s):  
Marin Ugrina ◽  
Martin Gaberšek ◽  
Aleksandra Daković ◽  
Ivona Nuić
Keyword(s):  
Chemical Modification ◽  
Aqueous Solutions ◽  
Specific Surface ◽  
Surface Area ◽  
Natural Zeolite ◽  
Contact Time ◽  
Liquid Ratio ◽  
X Ray ◽  
Solid Liquid

Sulfur-impregnated zeolite has been obtained from the natural zeolite clinoptilolite by chemical modification with Na2S at 150 °C. The purpose of zeolite impregnation was to enhance the sorption of Hg(II) from aqueous solutions. Chemical analysis, acid and basic properties determined by Bohem’s method, chemical behavior at different pHo values, zeta potential, cation-exchange capacity (CEC), specific surface area, X-ray powder diffraction (XRPD), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), as well as thermogravimetry with derivative thermogravimetry (TG-DTG) were used for detailed comparative mineralogical and physico-chemical characterization of natural and sulfur-impregnated zeolites. Results revealed that the surface of the natural zeolite was successfully impregnated with sulfur species in the form of FeS and CaS. Chemical modification caused an increase in basicity and the net negative surface charge due to an increase in oxygen-containing functional groups as well as a decrease in specific surface area and crystallinity due to the formation of sulfur-containing clusters at the zeolite surface. The sorption of Hg(II) species onto the sulfur-impregnated zeolite was affected by the pH, solid/liquid ratio, initial Hg(II) concentration, and contact time. The optimal sorption conditions were determined as pH 2, a solid/liquid ratio of 10 g/L, and a contact time of 800 min. The maximum obtained sorption capacity of the sulfur-impregnated zeolite toward Hg(II) was 1.02 mmol/g. The sorption mechanism of Hg(II) onto the sulfur-impregnated zeolite involves electrostatic attraction, ion exchange, and surface complexation, accompanied by co-precipitation of Hg(II) in the form of HgS. It was found that sulfur-impregnation enhanced the sorption of Hg(II) by 3.6 times compared to the natural zeolite. The leaching test indicated the retention of Hg(II) in the zeolite structure over a wide pH range, making this sulfur-impregnated sorbent a promising material for the remediation of a mercury-polluted environment.

scholarly journals Preparation and Characterization of Novel Magnesium Composite/Walnut Shells-Derived Biochar for As and P Sorption from Aqueous Solutions

Agriculture ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 714
Author(s):  
Vladimír Frišták ◽  
Martin Pipíška ◽  
Vladimír Turčan ◽  
Stephen M. Bell ◽  
Haywood Dail Laughinghouse ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Anthropogenic Sources ◽  
Walnut Shell ◽  
Natural Ecosystems ◽  
Functional Changes ◽  
P Sorption ◽  
Sorption Efficiency ◽  
Walnut Shells ◽  
Potential Capacity ◽  
Sorption From Aqueous Solutions

Elevated or unnatural levels of arsenic (As) and phosphorus (P) concentrations in soils and waterbodies from anthropogenic sources can present significant hazards for both natural ecosystems and human food production. Effective, environmentally friendly, and inexpensive materials, such as biochar, are needed to reduce mobility and bioavailability of As and P. While biochar features several physicochemical properties that make it an ideal contaminant sorbent, certain modifications such as mineral-impregnation can improve sorption efficiencies for targeted compounds. Here, we conducted sorption experiments to investigate and quantify the potential utility of magnesium (Mg) for improving biochar sorption efficiency of P and As. We synthesized a Mg-modified walnut shells-derived biochar and characterized its ability to remove As and P from aqueous solutions, thereby mitigating losses of valuable P when needed while, at the same time, immobilizing hazardous As in ecosystems. SEM-EDX, FTIR and elemental analysis showed morphological and functional changes of biochar and the formation of new Mg-based composites (MgO, MgOHCl) responsible for improved sorption potential capacity by 10 times for As and 20 times for P. Sorption efficiency was attributed to improved AEC, higher SSA, chemical forms of sorbates and new sorption site formations. Synthetized Mg-composite/walnut shell-derived biochar also removed >90% of P from real samples of wastewater, indicating its potential suitability for contaminated waterbody remediation.

Synthesis and Characterization of Chitosan/Fluorapatite Composites for the Removal of Cr (VI) from Aqueous Solutions and Optimized Parameters

2020 ◽  
Vol 231 (4) ◽  
Author(s):  
Rachid El Kaim Billah ◽  
Youness Abdellaoui ◽  
Zakaria Anfar ◽  
Germán Giácoman-Vallejos ◽  
Mahfoud Agunaou ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Synthesis And Characterization

Characterization of Structural Changes of Poly(vinyl methyl ether) γ-Irradiated in Diluted Aqueous Solutions

Langmuir ◽  
2004 ◽  
Vol 20 (7) ◽  
pp. 2883-2889 ◽  
Author(s):  
Claudia Querner ◽  
Thomas Schmidt ◽  
Karl-Friedrich Arndt
Keyword(s):  
Aqueous Solutions ◽  
Methyl Ether ◽  
Structural Changes ◽  
Vinyl Methyl ◽  
Vinyl Methyl Ether

scholarly journals Über Isopolywolframatfeststoffe und deren Beziehung zu Isopolywolframationen in wäßriger Lösun / Concerning Solid Isopolytungstates and their Relation to Isopolytungstate Ions in Aqueous Solutio

1975 ◽  
Vol 30 (11-12) ◽  
pp. 834-841 ◽  
Author(s):  
Vasile Cordis ◽  
Karl-Heinz Tytko ◽  
Oskar Glemser
Keyword(s):  
Aqueous Solutions ◽  
Reaction Scheme

A classification and characterization of the solid isopolytungstates obtainable from acidified aqueous solutions is given and the relation of the solid isopolytungstates to the isopolytungstate ions in the corresponding solutions is studied. As distinguished from the molybdate system all the polytungstate ions forming a solid exist in solution as well. The reasons for the non-occurrence of insoluble solids of species absent from solution are discussed. For setting up a reaction scheme on the polytungstates only very few of the large number of papers on this subject give evidentiary informations.

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