Search

Cesium removal from aqueous solutions of radioactive waste streams is a challenge in the field of radioactive waste management; this is due to the small atomic radii of Cs+ metal ions and their high migration ability. So, the development of a withstand system for the removal of Cs+ is crucial. In the current study, the removal of radioactive cesium from aqueous solutions using an RO-TLC membrane was studied. Two modifications were conducted; the first is to enlarge the cesium metal ion radii by interacting with mono- and dibasic acids, namely, stearic acid, tartaric acid, citric acid, and EDTA, and the second is the modification of the RO membrane pore size via reaction with the same acids. The modification was confirmed using SEM, FTIR, and EDX analysis techniques. The Cs+ and K+ rejection capacities and water permeability across the membrane at 1.5 bars were evaluated. Along with using the above-mentioned acids, the Cs+ metal ion retention index (RCs) was also obtained. It was found that employing EDTA as a chelating agent in an amount of 1.5 g/L in conjunction with the variation of feed content since it provided the highest value of RCs ~ 98% when used. Moreover, the elution of Cs+ using water, EDTA, ammonia, and HCl is also investigated. The optimal value of the eluent concentration was (0.25 M) HCl. Finally, Langmuir and Freundlich isotherm models were applied for a better understanding of the sorption process. The results of the present work more closely match the Langmuir isotherm model to determine the dominance of the chemical sorption mechanism. [ABSTRACT FROM AUTHOR]

Fertilizer industry is one of the most important industries to increase agricultural production and provide food for the world's population. In fertilizer factories, water is used to remove dust, cooling towers and different production processes, So It was mandatory to find new ways to solve water problems in such industries and reuse them again. wastewater from such industry in general contain organics, inorganic and suspended solids. The production process of potassium sulfate fertilizer results in sulphate-rich wastewater, while calcium-rich wastewater is produced by the calcium chloride industry. The confluence of this water leads to calcium sulfate being the basins of the wastewater treatment plant causing the pumps to stop working and blocking the filter press pores. due to the solidity of calcium sulphate, it causes an obstacle to get rid of it, extra effort, high cost, disruption of the station and stopping production factories which leads to a great economic loss. The current focus of work to solve this problem by adding organic chelators to effluent streams at a certain weight leading to the formation of calcium and sulphate chelates which can be easily isolated and get rid of calcium and sulphate ions. These chelators were prepared and tested to remove calcium and sulphate ions. The physicochemical properties of these chelators were characterized by several techniques such as Infrared spectroscopy, 1 H-NMR spectra and Mass spectrum. It was seen that the removal of calcium and sulphate ions using these organic chelators was the best way to treat industrial wastewater rich in such ions. [ABSTRACT FROM AUTHOR]

Sorption of La3+, Eu3+, and Fe3+ onto new synthetic inorganic ion exchange material of aluminum silicotitante was investigated. The aluminum silicotitante (EX1, EX2, and EX3) are synthetic with different concentration ratio (0.1:0.1:0.003, 0.1:0.1:0.1, and 0.1:0.1:0.1) at aging time 4, 4, and 1 day, respectively. The equilibrium kinetic for La3+, Eu3+, and Fe3+ onto EX1, EX2, and EX3 materials takes about 120 min which is considered as a fast kinetic process. Sorption results were fitted using different kinetic models such as pseudo-first-order, pseudo-second order, and intraparticle diffusion models. The results indicated that the sorption of La3+, Eu3+, and Fe3+ onto EX1, EX2, and EX3 materials is highly fit with the pseudo-second order model. Equilibrium data were described by the Langmuir, Freundlich isotherm models. The Langmuir isotherm model was fitted to the experimental data better than the Freundlich isotherm. The thermodynamics parameters (positive values of ΔH°, ΔS° and negative values of ΔG°) indicated the binding systems between the materials and adsorbate were endothermic, entropy gained and spontaneous in nature. The experimental data indicated that, aluminum silicotitante could be used as an efficient sorbent for La3+, Eu3+, and Fe3+. Maximum sorption % at equilibrium is 92.7, 99.0, and 78.5% for La3+, Eu3+, and Fe3+, respectively. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the performance of two pilot horizontal flow constructed wetlands (HFCWs) with and without vegetation. Three types of plants namely Canna, Phragmites australis and Cyprus papyrus were used. The surface area of each plant was 654 m2. The flow rate was 20 m3 d-1 and the organic loading rate range was 1.7-3.4 kg BOD d-1 with a detention time of 11 days. The results obtained showed that planted HFCW produced high quality effluent in terms of reduction of chemical oxygen demand (COD; 88%), biochemical oxygen demand (BOD; 91%) and total suspended solids (TSS; 92%) as well as nutrient removal. In addition, 4 logs of total coliform were removed from the planted unit compared with only 3 logs in the unplanted one. The phosphate uptake by the plants reached 29, 30.91 and 38.9 g P m-2 for Canna, Phragmites and Cyprus, respectively, with 60% removal rate in the treated effluent. The nitrogen uptake by the same plants reached 63.1, 49.46 and 82.33 g N m-2. Although, the unplanted unit proved to be efficient in the removal of COD, BOD and TSS, it lacks efficiency in pathogen and nutrient removal. The reclaimed wastewater, after disinfection, could be reused for non-restricted irrigation purposes [ABSTRACT FROM AUTHOR]

A new series of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Sr(II), Hg(II), Ag(I), Tl(I) and UO2(II) complexes of 2-(2-(4-carboxyphenyl)guanidino)acetic acid ligand have been synthesised and characterised by elemental analyses, IR, UV-Vis spectra, mass spectra (ligand and its zinc(II) complex), 1H NMR spectra (ligand and its mercury(II) complex), magnetic moments, conductances, thermal analyses (DTA and TGA) and ESR measurements. The IR data show that, the ligand behaves as neutral tridentate, (2), [(H2L)3Cu2(OAc)4(H2O)2], neutral bidentate, (3), [(H2L)Cu (OAc)2].1/2H2O, (13), [(HL)2CuCl2(H2O)2], (17), [(H2L)Cu(OOSO2)(H2O)3], dibasic hexadentate, (4), [(L)Ni4(OAc)6(H2O)10].4H2O, (5), [(L)Mn4(OAc)6(H2O)10].4H2O, (6), [(L)Co4(OAc)6(H2O)10].4H2O, monobasic bidentate, (7), [(HL)(UO2)(OAc)(H2O)3], (12), [(HL)2Cu], (15), [(HL)2Fe2(Cl4)(H2O)2].7H2O, (16), [(HL)2Cr2(Cl4)(H2O)2].7H2O, (21), [(H2L)Cd (OOSO2)(H2O)3].2H2O, monobasic tridentate, (8), [(L)2Hg2(OAc)2(H2O)6].H2O, (9), [(L)2Zn2(OAc)2(H2O)6].H2O, (10), [(L)2Cd2(OAc)2(H2O)6].H2O, (11), [(L)Tl4(OAc)3 (H2O)6], (18), [(HL)(OH)Cr2(SO4)2(H2O)5].H2O, (19), [(HL)3 Ag3NO3], or dibasic tridentate, (14), [(L)Sr(Cl)20(H2O)24], (20), [(L)3Cu(H2O)2]. Molar conductances in DMF indicate that, the complexes are non-electrolyte. The ESR spectra of Cu(II) complexes (2), (3) and (20) at room temperature show axial type symmetry with g// > g⊥ > 2.00, indicating a d(x2-y2) ground state with significant covalent bond character in an octahedral or square planar geometry. However, Cu(II) complexes (12) and (13) show isotropic type, indicating square planar and octahedral structure. Complexes Mn(II) (5) and Co(II) (6) show broad signals in the low field region indicating spin exchange interaction take place between metal(II) ion. Hg(II) complex (9), Tl(I) complex (11), Cr(III) complex (16), Cu(II) complex (17) and Cd(II) complex (21) showed potential antiproliferative activity where they showed inhibitory effect on breast carcinoma (MCF-7 cell line) in comparing with the standard drug. [ABSTRACT FROM AUTHOR]