Surface modification of thin film composite forward osmosis membrane using graphene nanosheets for water desalination.

In this study, the main motivation of this work is desalination of water for irrigation arid area such as Sidri- Baba basins- south Sinai, Egypt. Also, the novelty of this work is modification of TFC surface membrane by mix of HA, DA and GO to get high performance of FO technique. Interfacial polymerization was employed to modify a thin-film composite (TFC) membrane for forward osmosis (FO) applications; moreover, graphene oxide (GO) nanosheets (GONs), a dopamine solution (DA), and naturally accessible humic acid (HA) were modified on a polyethersulfone (PES) substrate. The effects of the different quantities of GO, HA, and DA on the membrane surfaces, as well as their various cross-sectional morphologies and FO-desalination capabilities, were investigated. The integrated TFC membrane containing appropriate GO, HA, and DA blends outperformed the control membrane, obtaining high water flux, and high salt rejection. Furthermore,.

Microstructure of gamma-ray developed polymeric nanocomposite respecting cesium and cobalt removal from aqueous solutions.

The nanoparticles of fly ash (FA) were obtained by high energy ball milling of their parent Class C kind for subsequent synthesis of poly(acrylamide-acrylic acid)/fly ash (poly(AM-AA)/FA) nanocomposite. The gamma-radiation induced polymerization was applied to achieve this concern. Different techniques were utilized to characterize such nanocomposite. The sorption abilities of the synthesized nanocomposite toward 60Co2+ and 134Cs + radionuclides were evaluated using batch and fixed-bed column approaches. Batches were designed at constants of solution pH (6.5-7.0 ± 0.02), nanocomposite particle size and dosage (106-250 µm and 0.1 L/g, respectively). The microstructure of such nanocomposite (<100 nm) was mainly amorphous with porous rough surfaces containing homogenous distribution of the incorporated nano-FA. About 56.46 and 47.9 mg/g of Co2+ and Cs+ were sorbed at equilibrium with an ion exchange reaction mechanism. Langmuir, Freundlich and Dubinin-Radushkevich D-R isotherm model parameters were calculated indicating the favorability of all sorption processes. The spontaneous and endothermic natures of sorption were observed by the calculated ΔG° and ΔH° thermodynamic parameters, respectively. Thomas, Yoon-Nelson and Adams Bohart models were fitted to the fixed-bed column data at varied conditions. The predicted sorption capacities of Thomas were very close to those obtained experimentally. Modeling of the fixed-bed column data dominates that the external mass transfer kinetics was predominant in the initial parts of the fixed-beds. Values required for retaining 50% of the initial sorbate concentration were extended from 89.05 to 68.55 to 177.2 and 149.3 min for 60Co2+ and 134Cs + radionuclides, respectively, by increasing bed depth from 1.5 to 3.0 cm. Modification of FA to its nano-scale form with the subsequent synthesis of a nanocomposite material having sorption capabilities made a duplicate beneficial environmental concern.

Increasing 2 -Bio- (H2 and CH4) production from food waste by combining two-stage anaerobic digestion and electrodialysis for continuous volatile fatty acids removal.

A novel approach of using two stage anaerobic digestion coupled with electrodialysis technology has been investigated. This approach was used to improving bio hydrogen and methane yields from food waste while simultaneously producing a green chemical feedstock. The first digester was used for hydrogen production and the second digester was used for methane production. The first digester was combined with continuous separation of volatile fatty acids using electrodialysis. The concentrations of carbohydrates, proteins and fats in the prepared food waste were 22.7%, 5.7% and 5.2% respectively. Continuous removal of volatile fatty acids during fermentation in the hydrogen digester not only increased hydrogen yields but also increased the production rate of volatile fatty acids. As a result of continuous VFA separation, hydrogen yields increased from 17.3 mL H2/g VS fermenter to 33.68 mL H2/g VS fermenter. Methane yields also increased from 28.94 mL CH4/g VS fermenter to 43.94 mL CH4/g VS fermenter. This represents a total increase in bio-energy yields of 77.1%. COD reduced by 73% after using two stage anaerobic digestion, however, this reduction increased to 86.7% after using electrodialysis technology for separation of volatile fatty acids. Electrodialysis technology coupled with anaerobic digestion improved substrate utilization, increased bioenergy yields and looks to be promising for treating complex wastes such as food waste.

Lanthanide complexes of spiropyran photoswitch and sensor: spectroscopic investigations and computational modelling.

A number of novel lanthanide (Gd3+, Sm3+, and Tb3+) complexes of the 1',3'-dihydro-8-methoxy-1',3',3'-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-(2H)-indole] (spiropyran; SP), a widely studied molecular photoswitch, were investigated. Comparative spectroscopic (absorption and fluorescence) and kinetic investigations of the stimulated photochromic and solvatochromic behavior were carried out in different media. SP embedded in a rigid thin film of poly(methylmethacrylate) might be exploited profitably as an optical sensor for the identification of a solvent's nature. Furthermore, thermodynamic parameters, in particular, Gibbs' free energy change (ΔG°), were derived using density functional theory quantum chemical calculations with the SP and merocyanine coloured form. The model used was the B3LYP/6-31G(d,p)/SCRF = (SMD, solvent) and its time-dependent extension procedure was used to quantitatively explain the structural isomerization in response to a variety of stimuli, such as light, solvent nature, lanthanide(iii) ions, and macromolecular support. These findings might be useful for the design of photoswitchable and energy transfer materials and their related fields.

Baseline evaluation for natural radioactivity level and radiological hazardous parameters associated with processing of high grade monazite.

Egyptian monazite is a promising resource and investment attractive for production of valuable metals of industrial or nuclear interest such as rare earth elements (REEs), thorium (Th) and uranium (U). The study was focused to establish a baseline framework in viewpoint of radiation protection for the workers in production of REEs from high-grade monazite treated by sodium hydroxide (NaOH) solutions. Radiological hazard indices (cancer, gonadal and other risks) were evaluated, due to emissions (α-, ß- and γ-radiations) of radium-isotopes (228Ra, 226Ra, 223Ra) and lead (210Pb). The values of the estimated radiological hazard indices were higher than the permissible safe limits, worldwide average and varied with those reported in other countries. It was found that more than 70% of radioactivity and radiological hazardous indices resulted from emissions of 228Ra, while the rest was attributed to 226Ra, 223Ra and 210Pb. Therefore, processing of the Egyptian monazite can cause a significant radiological impact on workers through external exposure from γ-radiations and/or internal exposure through inhalation or ingestion airborne contaminated by the radionuclides. Thus, the results recommended that protection rules could be considered to prevent the radiation hazards associated with the production of the REEs from the high grade monazite attacked by caustic method.

Synthesis, characterization and application of titanium oxide nanocomposites for removal of radioactive cesium, cobalt and europium ions.

New nanocomposite material containing TiO2/Poly (acrylamide-styrene sodium sulfonate) [TiO2/(P (AAm-SSS)] was prepared by in-situ intercalative polymerization of poly acrylamide (PAAm) and styrene sodium sulfonate (SSS) in the presence of TiO2 nanoparticles as inorganic filler. N, N-methylene bis acrylamide (MBA) was used as a cross linker. The polymerization process was performed using γ-radiation as reaction initiator. Moreover, new nanocomposite material containing poly styrene-TiO2 (PS-TiO2) was also prepared by ionic polymerization method. Styrene was catalytically polymerized by Ti(4+) via an ionic polymerization route to produce polystyrene (PS). The structure characteristics of the nanocomposites were investigated by XRD, TGA, SEM, surface area, and FTIR. The nanoparticles and nanocomposites were investigated for removal of some metal ions from aqueous solutions. The effective key parameters on the sorption behavior of radioactive cesium (Cs(+)), cobalt (Co(2+)) and europium (Eu(3+)) were investigated using batch equilibrium technique with respect to solution pH and contact time. The obtained results revealed that the equilibrium for Cs(+), Co(2+) and Eu(3)(+) is reached at 2-3 h for all nanocomposites. The data indicated that there is no significant change in the uptake between TiO2 nanoparticles and TiO2-PS. On the contrary, the uptake process is significantly improved using TiO2/(P (AAm-SSS) nanocomposite and the maximum experimental retention capacities for Cs(+), Co(2+) and Eu(3+) were found to be 120, 100.9 and 85.7 mg/g, respectively.

Spectroscopic and structural studies of the Schiff base 3-methoxy-N-salicylidene-o-amino phenol complexes with some transition metal ions and their antibacterial, antifungal activities.

Spectroscopic (IR, Raman, NMR, UV-visible, and ESR), and structural studies of the ligand 3-methoxy-N-salicylidene-o-amino phenol (H2L) and its synthesized complexes with some transition metal ions (Mn(II), Co(II), Ni(II)), Cu(II) and Zn(II)) were recorded and analyzed. The magnetic properties and thermal gravimetric analysis (TGA and DTA) were also measured for the complexes. The metal complexes were found to have The structural formula ML⋅H2O and the metal ions Mn(II), Co(II), Ni(II)) and Zn(II) were found to form tetrahedral complexes with the ligand whereas Cu(II) formed a square planar one. Antimicrobial activity of the ligand and its complexes were also investigated and discussed.

Uranyl ions adsorption by novel metal hydroxides loaded Amberlite IR120.

In this work, Ni(OH)2-loaded Amberlite IR120 (Ni-MA) and Co(OH)2-loaded Amberlite IR120 (Co-MA) resins were prepared, characterized and applied for UO2(2+) removal from aqueous solutions. The adsorption characteristics were investigated in a batch system with respect to effect of contact time, pH, equilibrium isotherms and removal kinetics data. The results indicated that the UO2(2+) could be efficiently removed from aqueous solutions at pH = 3.5 using Ni-MA and Co-MA resins. The maximum adsorption capacities for the UO2(2+) of Ni-MA and Co-MA were found to be 439 mg/g and 451 mg/g respectively. The equilibrium data fit well with the Langmuir adsorption isotherm. Kinetics study showed that the adsorption process was fast and reached equilibrium within 60 min and the kinetics data fit well with pseudo-second order and intra-particle diffusion models for both resins. The adsorption mechanism has been proposed and discussed. It was found that both Ni-MA and Co-MA resins could be used effectively for UO2(2+) removal from aqueous solutions.

Utilization of different crown ethers impregnated polymeric resin for treatment of low level liquid radioactive waste by column chromatography.

The main goal of this study was to find a novel impregnated resin as an alternative for the conventional resin (KY-2 and AN-31) used for low and intermediate level liquid radioactive waste treatment. Novel impregnated ion exchangers namely, poly (acrylamide-acrylic acid-acrylonitril)-N,N'-methylenedi-acrylamide-4,4'(5')di-t-butylbenzo 18 crown 6 [P(AM-AA-AN)-DAM/DtBB18C6], poly (acrylamide-acrylic acid-acrylonitril)-N,N'-methylenediacrylamide-dibenzo 18 crown 6 [P(AM-AA-AN)-DAM/DB18C6], and poly (acrylamide-acrylic acid-acrylonitril)-N,N'-methylenediacrylamide-18 crown 6 [P(AM-AA-AN)-DAM/18C6] were prepared and their removal efficiency of some radionuclides was investigated. Preliminary batch experiments were performed in order to study the influence of the different derivatives of 18 crown 6 on the characteristic removal performance. Separation of (134)Cs, (60)Co, (65)Zn and ((152+154))Eu radionuclides from low level liquid radioactive waste was investigated by using column chromatography with P(AM-AA-AN)-DAM/DtBB18C6 and metal salt solutions traced with the corresponding radionuclides. Breakthrough data was obtained in a fixed bed column at room temperature (298K) using different bed heights and flow rates. The breakthrough capacities were found to be 94.7, 83.3, 58.7, 43.1 (mg/g) for (60)Co, (65)Zn, (134)Cs, and ((152+154))Eu, respectively. Pre-concentration and separation of all radionuclides under study have been carried out using different concentration of nitric and/or oxalic acids.

Mobility of radionuclides in soil/groundwater system: comparing the influence of EDTA and four of its degradation products.

The adsorption behavior of 241Am, 60Co, 137Cs and 85Sr in the presence and absence of chelating ligands (ethylenediaminetetraacetic acid, ethylenediaminediacetic acid, hydroxyethyliminodiacetic acid, iminodiaceiticacid and methyliminodiacetic acid) was investigated. Sorption affinity in the absence of chelating ligands followed: Am(III)>Co(II)>Cs(I)>Sr(II). The presence of chelating ligands generally had little effect on sorption of 85Sr and 137Cs with Kd values 110 and 690 mL g(-1), respectively. But at 0.02 M of ethylenediaminetetraacetic or hydroxyethyliminodiacetic, the Kd decreased to 5 or 63 mL g(-1), respectively, where thermochemical modeling indicated almost all 85Sr is complexed with these ligands. The Kd values for 241Am and 60Co generally decreased with increasing chelating agent concentrations. In notable cases, the Kd values for Am increased at specific concentrations of 10(-3) M for IDA, MIDA and 10(-4) M for EDDA. This is proposed to be due to formation of a ternary surface complex.

Sorption reaction mechanism of some hazardous radionuclides from mixed waste by impregnated crown ether onto polymeric resin.

A novel impregnated polymeric resin was practically tested as adsorbent material for removal of some hazardous radionuclides from radioactive liquid waste. The applicability for the treatment of low-level liquid radioactive waste was investigated. The material was prepared by loading 4,4'(5')di-t-butylbenzo 18 crown 6 (DtBB18C6) onto poly(acrylamide-acrylic acid-acrylonitril)-N, N'-methylenediacrylamide (P(AM-AA-AN)-DAM). The removal of (134)Cs, (60)Co, (65)Zn , and ((152+154))Eu onto P(AM-AA-AN)-DAM/DtBB18C6 was investigated using a batch equilibrium technique with respect to the pH, contact time, and temperature. Kinetic models are used to determine the rate of sorption and to investigate the mechanism of sorption process. Five kinetics models, pseudo-first-order, pseudo-second-order, intra-particle diffusion, homogeneous particle diffusion (HPDM), and Elovich models, were used to investigate the sorption process. The obtained results of kinetic models predicted that, pseudo-second-order is applicable; the sorption is controlled by particle diffusion mechanism and the process is chemisorption. The obtained values of thermodynamics parameters, DeltaH degrees , DeltaS degrees , and DeltaG degrees indicated that the endothermic nature, increased randomness at the solid/solution interface and the spontaneous nature of the sorption processes.