Adsorption of Copper from aqueous solution by chitosan using molecular imprinting technology

In nature chitosan is a plentiful polymer with high heavy metal ion uptake capacity due to chitosan’s functional groups that chelate with the positive surfaces of heavy metal ions. In this study, epichlorohydrin was used as a crosslink to prepare the copper-imprinted chitosan as a pattern to enable the selectivity property and increase adsorption capacity. The effects of the cross-linker, PH, initial concentration and time were examined in this study to identify the optimum amount of each to remove copper metal ions from waste water by imprinted chitosan. This composite was characterized by Fourier-transform infrared spectroscopy (FTIR) test to determine the existence of copper ions in chitosan crosslinked with epichlorohydrin. Scanning electron microscopy (SEM) tests were also done to compare the surfaces of crosslinked chitosan and the removal of copper by imprinted chitosan. PH adsorption was tested from 3 to 7 and the initial concentration and time investigated were between 10 and 100 mg/l and 0 and 120 minutes respectively. The maximum capacity to adsorb was found to be at PH 7, initial concentration of 100mg/l at 90 minutes with 0.1 gr chitosan. Ultimately, the maximum adsorbent amount achieved for effective Cu(II) removal was 74.37 mg/g

Removal of cadmium (II) from aqueous solution by graphene oxid

Heavy metal ions are one of the principal contamination source and cause of difficulties in wastewater processing that requires being eliminated before discharging into the eco-system. Adsorption of cadmium (II) from an aqueous solution by graphene oxide has been considered. Recently, graphene oxide (GO) has taken a large amount of attention because of high mechanical strength and appropriate surface area that has provided to apply as strengthened materials, various oxygen functional groups on its surface and π-electron system. In this investigation, graphene oxide was employed as an effective and proper adsorbent for separating the cadmium (II) from aqueous solution. TEM, Raman, FT-IR, and SEM tests have been used for characterizing the graphene oxide. In the adsorption process, initial concentrations of aqueous solution examined from 20 to 100 mg/l; pH and contact time were investigated from 3 to 8 and 5 to 100 minutes respectively. Adsorption isotherm obeyed Langmuir, Freundlich, and Temkin that the maximum cadmium adsorption capacity has been taken from Langmuir fitting with 135.14 mg/g. Also, the kinetic considerations explained that the adsorption manner followed the pseudo-second-order kinetic model with R2. Thermodynamic investigations and parameters show the exothermic and spontaneous of adsorption

Hydrogen Production Using bacteria of Thermotoga maritime

ABSTRACT Hydrogen production from renewable sources such biomass derived from agricultural waste and municipal alternative ways require to reduce energy costs and consumption of oil and methane gas. Subscribe anaerobic organisms in the environment, such as landfills and cow rumen, methane and hydrogen as well as hydrogen sulfide is a gas stream is suitable for hydrogen fuel cells

Removal of cadmium (II) by graphene oxide-chitosan adsorbent from aqueous solution

Pollution has a negative influence on the environment and is necessary to eliminate from wastewater and aqueous solution. There are several adsorbents for removing the pollution, among them Graphene oxide and Chitosan are proper elements with great uptaking ability. In this investigation, graphene oxide surface was coated with chitosan paricles to remove the Cadmium (II) from aqueous solution. The impact of concentration, pH and time were studied to achieve the optimum conditions of adsorption. The adsorbent was analyzed by TEM, FT-IR, XRD, and SEM analysis. The outcomes presented that the adsorbent was prepared successfully. The concentration item was tested from 10 to 120 ppm. The pH and time items were studied from 3 to 8 value and from 5 to 140 minutes for eliminating cadmium (II) respectively. Freundlich and Langmuir's models was used and the pseudo-second-order was the best fitted kinetic model in this investigation. Conclusively, the maximum adsorption ability of the made adsorbent was achieved at 107.8 mg/g based on Langmuir isotherm

Synthesis and application of functionalized Graphene oxide-silica with chitosan for removal of Cd II fromaqueous solution

The functionalized graphene oxide by silica and chitosan helped to prepared an adsorbent with high adsorption potential for removing cadmium(II). In this study, the adsorbent was synthesized and the batch system of adsorption method was examined to find the potential of the new adsorbent with the various factors of the concentration, pH, time and temperature. The characterization of adsorbent was analyzed by FT-IR, TEM, Zeta potential and XRD analysis. Regards to the analysis it can be understood that the adsorbent was synthesized successfully. The investigational results were validated and analyzed by applying the 5 models of isotherm and 4 models of kinetic. The Langmuir, Freundlich, Temkin, Harkins-Jura and Dubinin-radushkevich models were used which the Langmuir, Freundlich and Temkin fitted well for removing cadmium(II). The Qmax value was achieved 126.58 mg/g by using the Langmuir model for removing Cd(II) respectively. The pseudo-first-order, pseudo-second-order, Elovich and Intra-particle models were used to validate the kinetic models of the process. The pseudo-second-order and Elovich models were the best fitted kinetic model in this investigation. Thermodynamic parameters of the energy of gibes, the enthalpy, and the entropy were calculated. Generally, the adsorption process was distinguished as an exothermic and spontaneous

Solar photocatalytic and surface enhancement of ZnO/rGO nanocomposite: degradation of perfluorooctanoic acid and dye

In this work, ZnO/rGO nanocomposites (NCs) were synthesized through a low temperaturesol–gel method. Zinc oxide decorated on graphene sheets could provide surface enhance-ment and hinder the rapid recombination rate of electron hole pairs that occur during aphotocatalysis process. It has been observed that the loading of ZnO decorated on graphenesheets is important in controlling the morphologies and surface enhancement of ZnO/rGONCs. Field Emission Scanning Electron Microscope (FESEM) micrographs reveal that spheri-cal shape and hexagonal-based nanopyramid of ZnO can be formed at low and high loadingof ZnO, respectively. NCs showed excellent performance for degradation of perfluorooc-tanoic acid (PFOA) and methyl orange in aqueous solution under solar irradiation. Herein,mechanisms for the formation of different shapes of ZnO nanostructures decorated ongraphene and their enhancement towards surface and photoactivity were discussed indetails

Synthesis and Characterisation of Graphene Oxide-Silica-Chitosan for Eliminating the Pb(II) from Aqueous Solution

Heavy metal ions have a toxic and negative influences on the environment and human health even at low concentrations and need to be removed from wastewater. Chitosan and graphene oxide are suitable nano plate adsorbents with high adsorption potential because of their π-π interaction, and they are available functional groups that interact with other elements. In this study, graphene oxide was coated with silica to enhance the hydrophilicity of the adsorbent. Subsequently, the adsorbent was functionalised by various amounts of chitosan to improve the Pb(II) removal. The adsorbent was analysed using transmission electron microscopy (TEM), Raman, Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and mapping analysis techniques. An investigation of the influences of the initial concentration of Pb(II), pH and contact time were included to obtain the optimum amount of adsorption. The range of the initial Pb(II) concentration studied was from 10 to 120 mg/L. The pH factor ranged from 3 to 8 with contact time from 0 to 140 min. Freundlich, Temkin and Langmuir isotherm models were fit to the results, and a pseudo-second-order kinetic model was found to provide a good fit as well. The maximum Pb(II) removal capacity achieved was 256.41 (+/− 4%) mg/g based on Langmuir isotherms

Simultaneous removal of Congo red and cadmium (II) from aqueous solutions using graphene oxide–silica composite as a multifunctional adsorbent

Graphene oxide is a very high capacity adsorbent due to its functional groups and π−π interactions with other compounds. Adsorption capacity of graphene oxide, however, can be further enhanced by having synergistic effects through the use of mixed-matrix composite. In this study, silica-decorated graphene oxide (SGO) was used as a high-efficiency adsorbent to remove Congo red (CR) and Cadmium (II) from aqueous solutions. The effects of solution initial concentration (20 to 120 mg/l), solution pH (pH 2 to 7), adsorption duration (0 to 140 min) and temperature (298 to 323 K) were measured in order to optimize the adsorption conditions using the SGO adsorbent. Morphological analysis indicated that the silica nanoparticles could be dispersed uniformly on the graphene oxide surfaces. The maximum capacities of adsorbent for effective removal of Cd (II) and CR were 43.45 and 333.33 mg/g based on Freundlich and Langmuir isotherms, respectively. Langmuir and Freundlich isotherms displayed the highest values of Qmax for CR and Cd (II) adsorption in this study, which indicated monolayer adsorption of CR and multilayer adsorption of Cd (II) onto the SGO, respectively. Thermodynamic study showed that the enthalpy (ΔH) and Gibbs free energy(ΔG) values of the adsorption process for both pollutants were negative, suggesting that the process was spontaneous and exothermic in nature. This study showed active sites of SGO (π-π, hydroxyl, carboxyl, ketone, silane-based functional groups) contributed to an enormous enhancement in simultaneous removal of CR and Cd (II) from an aqueous solution, Therefore, SGO can be considered as a promising adsorbent for future water pollution control and removal of hazardous materials from aqueous solutions