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EN
With the paramount development of industry and agriculture sector, levels of different pollutants like, heavy metal ions, pharmaceuticals, organic dyes, biological waste and other pollutants are becoming serious. The ecosystem and human health suffered greatly from the adverse effects of these pollutants. The disposal of these pollutants has become an urgent issue for the human society. Graphene oxide base nanocomposites have generated an excellent extent of focus as desirable alternatives for the adsorptive elimination of contaminants from aqueous systems owing to their enhanced surface area and multiple functional groups for adsorption. Graphene oxide (GO) as a graphene derivative exhibited superior features as obtainable in a graphene sheet. Moreover, the addition of oxygen functional group at the edges and basal plane of graphene further enhanced the efficiency of the graphene by providing sites for the attachment of different metals on the surface. On the underlying adsorption processes, graphene-based nanocomposites for specific contaminants are designed and currently employed for wastewater treatment. This review presents the ongoing development of GO base nanocomposites and their useful applications, understanding how well graphene-based nanocomposites adsorb pollutants and how that relates to the ways in which pollutants interact with adsorbents is crucial. This study highlights newly developed trends in the creation of graphene oxide based nanocomposites to eliminate different heavy metal ions, dyes, pharmaceuticals, and oils spills from effluent water. The focus is on various graphene oxides nanocomposites application for the removal of different pollutants and regeneration of graphene oxide base nanocomposites after several adsorption cycles. Other challenges and potential directions for designing efficient GO based nanocomposites as adsorbents are also presented along with the problems of current studies.
EN
In this study, activated carbon and humic acid powder were fixed by the cross-linking reaction of sodium alginate. Calcium alginate/activated carbon/humic acid (CAH) tri-system porous fibers were prepared by the wet spinning method and freeze-dried for the removal of tetracycline in aqueous solution. Subsequently, the morphology and structure of CAH fibers were measured by scanning electron microscopy (SEM) and the Brunauer-Emmett-Teller (BET) method. The effect of pH, contact time, temperature and other factors on adsorption behavior were analyzed. The Langmuir and Freundlich isotherm models were used to fit tetracycline adsorption equilibrium data. The dynamics data were evaluated by the pseudo-second-order model, the pseudo-second-order model and the intraparticle diffusion model. Thermodynamic study confirmed that the adsorption of tetracycline on CAH fibers was a spontaneous process.
EN
New kind of adsorbent was produced from Trichosanthes kirilowii Maxim shell. The KOH activation technology for preparation of Trichosanthes kirilowii Maxim shell activated carbon (TKMCK) was optimized. Using methylene blue as the sample adsorbate, the adsorption behavior was systematically investigated in terms of the activation agent and temperature, the adsorption temperature and time, the initial adsorbate pH and concentration, as well as the dosage of adsorbent. Surface physical morphology of the TKMCK prepared was observed by scanning electron microscopy (SEM), while the functional groups were determined with Fourier transform infrared (FTIR) spectra. Kinetic studies indicated that the adsorption process was more consistent with the pseudo-second-order kinetic. Both Langmuir and Freundlich isotherms were employed to fit the adsorption data at equilibrium, with the former giving a maximum adsorption capacity of 793.65 mg/g at 323 K. BET surface area of as-prepared TKMCK was 657.78 m2/g.
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Content available Enthalpy of isopropanol adsorption on zeolite
EN
The enthalpy of isopropanol adsorption on ZSM-5 (Zeolite Socony Mobil Framework Type MFI) was determined by the static adsorption method at the temperature range from 20°C to 100°C. Langmuir and Huttig models of equilibrium adsorption have been used to calculate the enthalpy of isopropanol adsorption at these conditions. Adsorption isotherms determined by the flow method at 20°C and 30°C have been also used in the calculations. The obtained values of isopropanol adsorption enthalpy were compared with the values of isopropanol evaporation enthalpy and with the results obtained from isopropanol and water desorption measurements with thermogravimetry and differential scanning calorimetry methods.
EN
A novel efficient adsorbent, alkali-pretreated Paeonia ostii seed coats (AP-PSC), was investigated for the removal of methylene blue (MB) dye from solution. Orthogonal array design was applied to optimize the process parameters viz. alkali concentration, liquid-solid ratio (LSR) and pretreatment time. The results revealed that the optimal pretreatment conditions were at 0.8% (w/w) NaOH with LSR of 0.35 L g–1  treating for 50 min. Equilibrium and kinetic studies indicated that Langmuir isotherm and Pseudo-second-order models described the experimental data well. The maximum adsorption capability was of 368.2 mg g–1  for MB at 25°C. Thermodynamic parameters suggested that the AP-PSC adsorption process was physical, endothermic and spontaneous. Furthermore, the adsorption process was influenced by several interactive mechanisms, including ion-exchange, as well as Van der Waals forces and hydrogen bonds that occur concomitantly. It was concluded that AP-PSC may be potential as an efficient adsorbent to remove MB from solution.
EN
The aim of the present work is to study the efficiency of a biocompatible polymer-based adsorbent for the removal of Pb (II) ions whose devastating effects on people’s health is a matter of great concern from aqueous solution. In this study, ethyl cellulose and gamma-Al2 O<3  nanoparticles/ethyl cellulose electrospun adsorbents were prepared for the batch removal of Pb (II) ions from aqueous solution. Both samples were characterized using contact angle analysis, N2 adsorption/desorption technique, FT-IR and SEM. The Freundlich model (R-square = 0.935 and RMSD (%) = 6.659) and the Dubinin-Radushkevich model (R-square = 0.944 and RMSD (%) = 6.145) were found to be more reliable in predicting the experimental data from the adsorption of Pb (II) ions onto the electrospun gamma-Al2 O<3  nanoparticles/ethyl cellulose than the Langmuir model (R-square = 0.685 and RMSD (%) = 14.61) and also the Temkin model (R-square = 0.695 and RMSD (%) = 14.38).
EN
Soybean curd is a very popular food containing high-quality protein, polyunsaturated fats, vitamins, minerals and other nutrients. This study aims to prepare porous soybean curd xerogels via a vacuum freeze drying method and uses them as adsorbents to remove congo red from aqueous solutions. The morphology and functional groups of the soybean curd xerogels were characterized using scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. The adsorption properties of congo red onto the soybean curd xerogels were carried out through investigating the influencing experimental parameters such as the drying method, solution pH, adsorbent dose, contact time and temperature. The results showed that the adsorption isotherm data were fitted well to the Freundlich isotherm. Adsorption kinetics of congo red onto the soybean curd followed the pseudo-second-order kinetic model. The thermodynamic parameters, such as ΔG°, ΔH° and ΔS°, were also determined.
EN
The main aim of this study was to evaluate the efficiency of natural zeolite for Cr(VI) removal from aqueous solutions. Following simple modification of adsorbent, the effect of operational parameters including pH (2–10), adsorbent dosage (2–20 g/L), contact time (5–150 min) and Cr(VI) concentration (10–50 mg/L) were studied according to one-factor-at-a-time procedure. The maximum Cr(VI) removal of 99.53% was obtained at initial pH of 2, contact time of 30 min, adsorbent dosage of 8 g/L and initial chromium concentration of 10 mg/L. The Freundlich isotherm was best fitted with experimental data (R2 = 0.951). Also, type 1pseudo second order kinetic model showed the most correlation (R2 = 1) with the experimental data. According to obtained results, it can be concluded that the application of clay-like adsorbents such as natural clinoptilolite zeolite can be considered as an efficient alternative for final treatment of effluents containing Cr(VI).
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