Adsorption Mechanism of Copper(II) Ions on Expansion-Treated Rice Husk

2011 ◽  
Vol 695 ◽  
pp. 13-16
Author(s):  
Xuan Liang ◽  
Xue Gang Luo ◽  
Xiao Yan Lin
Keyword(s):  
Removal Efficiency ◽  
Rice Husk ◽  
Photoelectron Spectroscopy ◽  
Adsorption Mechanism ◽  
Ph Value ◽  
Water Solution ◽  
Whole Process ◽  
Monolayer Adsorption ◽  
Strong Adsorption ◽  
Bulk Structures

Expansion-treated rice husk (ERH) had been used as adsorbent for removing copper(II) ions, and showed strong adsorption ability and removal efficiency for copper(II) ions. In this paper, the surface and bulk structures of ERH adsorbent were investigated by X-ray photoelectron spectroscopy (XPS) and scanning electronic microscopy (SEM), ERH was treated by water solution with different pH value, and the adsorption performance of ERH for copper(II) ions was investigated through adsorption static experiments in order to study the adsorption mechanism. The result showed that ERH treated by alkaline solution had high removal efficiency for copper(II) ions, the reason ascribed to the large surface area of ERH. ERH had competitive adsorption for H+ and Cu2+, and a monolayer adsorption process played an important role in the whole process.

Adsorption of lead using a novel xanthated carboxymethyl chitosan

2013 ◽  
Vol 69 (2) ◽  
pp. 298-304 ◽  
Author(s):  
Qingping Song ◽  
Chongxia Wang ◽  
Ze Zhang ◽  
Jiangang Gao
Keyword(s):  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Adsorption Mechanism ◽  
Ph Value ◽  
Carboxymethyl Chitosan ◽  
Langmuir Model ◽  
Maximum Adsorption Capacity ◽  
Visible Spectra ◽  
Initial Ph ◽  
Uv Visible

Adsorption of Pb(II) was studied using a novel xanthated carboxymethyl chitosan (XCC). The XCC was synthesized using the xanthation reaction of N-carboxymethyl chitosan (NCMC). The chemical structure of XCC was characterized by UV–visible spectra. The effects of initial pH value of the solutions, contact time and adsorption isotherms on adsorption of Pb(II) were investigated. Moreover, the possible adsorption mechanism was identified using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The experimental results showed XCC experienced a high adsorption capacity. The adsorption isotherm followed the Langmuir model. The maximum adsorption capacity obtained from the Langmuir model was 520.8 mg/g. Thermodynamic studies revealed a spontaneous and exothermic adsorption process. FTIR and XPS studies showed that the carboxyl groups, nitrogen atoms and sulfur atoms participated in the adsorption of Pb(II).

scholarly journals Synthesis of a Novel Ce-bpdc for the Effective Removal of Fluoride from Aqueous Solution

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Changqing Zhao ◽  
Yanwei Cui ◽  
Fang Fang ◽  
Si Ok Ryu ◽  
Jiarui Huang
Keyword(s):  
Adsorption Capacity ◽  
Removal Efficiency ◽  
Photoelectron Spectroscopy ◽  
Ph Value ◽  
Binding Capacity ◽  
Fluoride Removal ◽  
Maximum Adsorption Capacity ◽  
Fluoride Ions ◽  
X Ray ◽  
Fluoride Adsorption

Ce-1,1′-biphenyl-4,4′-dicarboxylic acid (Ce-bpdc), a novel type of metal organic framework, was synthesized and applied to remove excessive fluoride from water. The structure and morphology of Ce-bpdc were measured by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The effects, such as saturated adsorption capacity, HCO3-, and pH, were investigated. The optimal pH value for fluoride adsorption was the range from 5 to 6. The coexisting bicarbonate anions have a little influence on fluoride removal. The fluoride adsorption over the Ce-bpdc adsorbent could reach its equilibrium in about 20 min. The Ce-bpdc coordination complex exhibited high binding capacity for fluoride ions. The maximum adsorption capacity calculated from Langmuir model was high up to 45.5 mg/g at 298 K (pH = 7.0) and the removal efficiency was greater than 80%. In order to investigate the mechanism of fluoride removal, various adsorption isotherms such as Langmuir and Freundlich were fitted. The experimental data revealed that the Langmuir isotherm gave a more satisfactory fit for fluoride removal. Finally, the tested results of ground water samples from three places, Yuefang, Jiangji, and Sanyi which exhibited high removal efficiency, also demonstrate the potential utility of the Ce-bpdc as an effective adsorbent.

scholarly journals Removal of hexavalent chromium from wastewater by Cu/Fe bimetallic nanoparticles

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jien Ye ◽  
Yi Wang ◽  
Qiao Xu ◽  
Hanxin Wu ◽  
Jianhao Tong ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Removal Efficiency ◽  
Photoelectron Spectroscopy ◽  
Bimetallic Nanoparticles ◽  
Chemical Reduction ◽  
Particle Surface ◽  
Zerovalent Iron ◽  
Order Model ◽  
X Ray ◽  
Nanoscale Zerovalent Iron

AbstractPassivation of nanoscale zerovalent iron hinders its efficiency in water treatment, and loading another catalytic metal has been found to improve the efficiency significantly. In this study, Cu/Fe bimetallic nanoparticles were prepared by liquid-phase chemical reduction for removal of hexavalent chromium (Cr(VI)) from wastewater. Synthesized bimetallic nanoparticles were characterized by transmission electron microscopy, Brunauer–Emmet–Teller isotherm, and X-ray diffraction. The results showed that Cu loading can significantly enhance the removal efficiency of Cr(VI) by 29.3% to 84.0%, and the optimal Cu loading rate was 3% (wt%). The removal efficiency decreased with increasing initial pH and Cr(VI) concentration. The removal of Cr(VI) was better fitted by pseudo-second-order model than pseudo-first-order model. Thermodynamic analysis revealed that the Cr(VI) removal was spontaneous and endothermic, and the increase of reaction temperature facilitated the process. X-ray photoelectron spectroscopy (XPS) analysis indicated that Cr(VI) was completely reduced to Cr(III) and precipitated on the particle surface as hydroxylated Cr(OH)3 and CrxFe1−x(OH)3 coprecipitation. Our work could be beneficial for the application of iron-based nanomaterials in remediation of wastewater.

scholarly journals Microstructure and Properties of Self-Assembly Graphene Microcapsules: Effect of the pH Value

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 587 ◽  
Author(s):  
Yan-Dong Guo ◽  
Jun-Feng Su ◽  
Ru Mu ◽  
Xin-Yu Wang ◽  
Xiao-Long Zhang ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Chemical Engineering ◽  
Ph Value ◽  
Liquid Paraffin ◽  
Energy Dispersive Spectrometer ◽  
Core Material ◽  
Microstructure And Properties ◽  
Ph Values

Graphene has attracted attention in the material field of functional microcapsules because of its excellent characteristics. The content and state of graphene in shells are critical for the properties of microcapsules, which are greatly affected by the charge adsorption equilibrium. The aim of this work was to investigate the effect of pH value on the microstructure and properties of self-assembly graphene microcapsules in regard to chemical engineering. Microcapsule samples were prepared containing liquid paraffin by a self-assembly polymerization method with graphene/organic hybrid shells. The morphology, average size and shell thickness parameters were investigated for five microcapsule samples fabricated under pH values of 3, 4, 5, 6 and 7. The existence and state of graphene in dry microcapsule samples were analyzed by using methods of scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). Fourier Transform Infrared Spectoscopy (FT-IR) and Energy Dispersive Spectrometer (EDS) were applied to analyze the graphene content in shells. These results proved that graphene had existed in shells and the pH values greatly influenced the graphene deposition on shells. It was found that the microcapsule sample fabricated under pH = 5 experienced the largest graphene deposited on shells with the help of macromolecules entanglement and electrostatic adherence. This microcapsules sample had enhanced thermal stability and larger thermal conductivity because of additional graphene in shells. Nanoindentation tests showed this sample had the capability of deforming resistance under pressure coming from the composite structure of graphene/polymer structure. Moreover, more graphene decreased the penetrability of core material out of microcapsule shells.

Preparation of Sands Modified by Aluminous Salt and its Adsorption Capability of CD2+

2011 ◽  
Vol 130-134 ◽  
pp. 856-859
Author(s):  
Chun Sheng Ding ◽  
Yang Ping Fu ◽  
Qian Fen Zhu ◽  
Jing Fu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Influencing Factors ◽  
Removal Efficiency ◽  
Specific Surface Area ◽  
Quartz Sand ◽  
Ph Value ◽  
Alkaline Condition ◽  
Initial Concentration ◽  
Adsorption Capability

In this experiment quartz sand was chosen as a carrier to be coated by aluminous salt under alkaline condition, and then the specific surface area was tested, and the adsorption capability and Cd2+ removal influencing factors of modified sand were studied. The investigation results showed that the specific surface area of modified sand was 75.244m2/g which was 9.38 times of that of original sand; the removal efficiency of Cd2+ by aluminous salt modified sand reached 59% contrast to 39% of original sand with pH 7.00. It was also found that the removal efficiency of Cd2+ by the aluminous salt modified sand was reduced with the increase of initial concentration of Cd2+ solution, and was enhanced with the increase of pH value, the Cd2+ removal efficiency was almost 71% with pH 9.0.

scholarly journals Influence of thermal treatment and combustible additives on properties of Latvian clay ceramics pellets

2013 ◽  
Vol 7 (4) ◽  
pp. 175-180 ◽  
Author(s):  
Liga Dabare ◽  
Ruta Svinka
Keyword(s):  
Surface Area ◽  
Ph Value ◽  
Water Solution ◽  
Porous Ceramic ◽  
Mercury Porosimetry ◽  
Environmental Application ◽  
Wide Range ◽  
Different Temperatures ◽  
Ph Level ◽  
Clay Ceramics

Porous ceramic pellets for possible environmental application were produced from different Latvian clays by sintering at different temperatures. Their characteristics and influence of additives were analysed using X-ray diffraction, mercury porosimetry and BET tests. The obtained ceramic pellets from calcareous clays after immersion in distilled water change its pH value, which affects their capability to adsorb ions or molecules on the surface. The sorption capabilities are dependent on the pH level of water solution, composition of clays, and used adsorbate. Porosity of the produced pellets is mostly within range from 15 to 25 % throughout all sintering temperatures with a slight decrease at 1050 ?C. The specific surface area has a wide range up to 30 m2/g. The highest surface area has pellets sintered at lower temperatures. The adsorption capability of pellets was evaluated using water solutions with different ions. The most promising results were obtained with iodine sorption. For most pellets the sorption capacity was 12.7 mg/g, although for the pellets sintered at 1050 ?C it was lower.

scholarly journals Electrochemical oxidation of sulfamethoxazole using Ti/SnO2-Sb/Co-PbO2 electrode through ANN-PSO

2019 ◽  
Vol 84 (7) ◽  
pp. 713-727 ◽  
Author(s):  
Jiteng Wan ◽  
Chunji Jin ◽  
Banghai Liu ◽  
Zonglian She ◽  
Mengchun Gao ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Electrochemical Oxidation ◽  
Removal Efficiency ◽  
Current Density ◽  
Ph Value ◽  
Ann Model ◽  
Solution Ph ◽  
Pbo2 Electrode ◽  
Artificial Neural Network Ann ◽  
Major Factors

Even in a trace amounts, the presence of antibiotics in aqueous solution is getting more and more attention. Accordingly, appropriate technologies are needed to efficiently remove these compounds from aqueous environments. In this study, we have examined the electrochemical oxidation (EO) of sulfamethoxazole (SMX) on a Co modified PbO2 electrode. The process of EO of SMX in aqueous solution followed the pseudo-first-order kinetics, and the removal efficiency of SMX reached the maximum value of 95.1 % within 60 min. The effects of major factors on SMX oxidation kinetics were studied in detail by single-factor experiments, namely current density (1?20 mA cm-2), solution pH value (2?10), initial concentration of SMX (10?500 mg L-1) and concentration of electrolytes (0.05?0.4 mol L-1). An artificial neural network (ANN) model was used to simulate this EO process. Based on the obtained model, particle swarm optimization (PSO) was used to optimize the operating parameters. The maximum removal efficiency of SMX was obtained at the optimized conditions (e.g., current density of 12.37 mA cm-2, initial pH value of 4.78, initial SMX concentration of 74.45 mg L-1, electrolyte concentration of 0.24 mol L-1 and electrolysis time of 51.49 min). The validation results indicated that this method can ideally be used to optimize the related parameters and predict the anticipated results with acceptable accuracy.

scholarly journals Mechanism of the process of decomposition of apatitis with phosphoric acid

2019 ◽  
Vol 81 (1) ◽  
pp. 294-297
Author(s):  
R. F. Sabirov ◽  
A. F. Makhotkin ◽  
Yu. N. Sakharov ◽  
I. A. Makhotkin ◽  
I. Yu. Sakharov
Keyword(s):  
Phosphoric Acid ◽  
Ph Value ◽  
Batch Reactor ◽  
Experimental Studies ◽  
Hydrogen Ions ◽  
Experimental Conditions ◽  
Monocalcium Phosphate ◽  
Ph Values ◽  
Whole Process ◽  
Proportional Increase

Experimental studies of the kinetics and mechanism of the process, decomposition of apatite by phosphoric acid, in the Apatite-H3PO4-H2O system without the addition of sulfuric acid have been performed. The study of the decomposition process of Kovdorsky apatite with certain particle sizes was carried out in a batch reactor with a volume of 1 dm3 with stirring of the reaction mixture, and an initial concentration of phosphoric acid of 17% by weight, at a temperature of 78–82 °C. Observation of the process was carried out by determining the concentration of phosphoric acid and the concentration of monocalcium phosphate. The acidity of the reaction mixture was determined by the pH meter readings (pH-105 MA with a glass combined-ESC-10603 electrode). It was shown that during the whole process a constant smooth increase in the pH value of the reaction mixture to pH 6 occurs. Comparison of the pH values of the reaction mixture during the actual at the time of determining the concentration of phosphoric acid and pH of phosphoric acid of the corresponding concentration in the aqueous solution shows that the pH value of the reaction mixture is significantly affected by the presence of monocalcium phosphate gel. During the process, during the first thirty minutes, the concentration of phosphoric acid decreases from 17 to 10% by weight, the corresponding quantitative formation of monocalcium phosphate gel and a proportional increase in the pH of the reaction mixture. Then, as the concentration of phosphoric acid decreases, the process slows down and does not proceed to the end under the experimental conditions. The dependence of the concentration of hydrogen ions in the reaction mixture on the time of the process of decomposition of apatite in phosphoric acid, which is presented in logarithmic coordinates, shows that the mechanism of formation of hydrogen ions during the whole process does not change. Thus, it is shown that the process of decomposition of apatite by phosphoric acid in the Apatite-H3PO4-H2O system proceeds with the formation of an intermediate product - monocalcium phosphate gel. When this occurs, a corresponding significant change in the pH values of the reaction mixture occurs. During the whole process there is a constant decrease in the concentration of phosphoric acid.

scholarly journals Comparison of sorption efficiency of natural and MnO2 coated zeolite for copper removal from model solutions

2021 ◽  
Vol 900 (1) ◽  
pp. 012003
Author(s):  
M Balintova ◽  
Z Kovacova ◽  
S Demcak ◽  
Y Chernysh ◽  
N Junakova
Keyword(s):  
Heavy Metals ◽  
Removal Efficiency ◽  
Ph Value ◽  
Batch Experiments ◽  
Modified Zeolite ◽  
Optimum Ph ◽  
Removal Of Heavy Metals ◽  
Initial Ph ◽  
Correlation Factors ◽  
Maximum Removal

Abstract Removal of heavy metals from the environment is important for living beings. The present work investigates the applicability of the natural and MnO2 - coated zeolite as sorbent for the removal of copper from synthetic solutions. Batch experiments were carried out to identify the influence of initial pH and concentration in the process of adsorption. A maximum removal efficiency of Cu(II) was observed in 10 mg/L for natural (95.6%) and modified (96.4%) zeolite, where the values was almost identical, but at concentration of 500 mg/L was the removal efficiency of modified zeolite three times higher. Based on the correlation factors R2, the Langmuir isotherms better describe the decontamination process than Freundlich. The optimum pH value was set at 5.0.

scholarly journals Aqueous poly(N-Vinylformamide-co-Vinylamine) as a suitable adhesion promoter for wood veneer/biopolyethylene composite materials

BioResources ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. 8134-8159
Author(s):  
Rico John ◽  
Katja Trommler ◽  
Katja Schreiter ◽  
Carolin Siegel ◽  
Frank Simon ◽  
...  
Keyword(s):  
Composite Materials ◽  
Photoelectron Spectroscopy ◽  
Ph Value ◽  
Structural Parameters ◽  
Degree Of Hydrolysis ◽  
Adhesion Promoter ◽  
Wood Veneer ◽  
X Ray ◽  
Young’S Moduli ◽  
Veneer Surface

Wood veneer/biopolyethylene (bio-PE) biocomposite materials were produced by using poly(N-vinylformamide-co-vinylamine) (PVFA-co-PVAm) copolymers as a phase-mediating reagent. In a preliminary step, PVFA-co-PVAm was adsorbed onto the wood veneer component from aqueous solution. In its adsorbed form, it served as an adhesion promoter and improved the compatibility between both the highly polar wood veneer and weakly polar bio-PE surface. Structural parameters and their effect on the adsorption process, such as the degree of hydrolysis (DH) of poly(N-vinylformamide) (PVFA) (30, 50, and > 90%), the molecular weight of PVFA-co-PVAm (Mw 10,000, 45,000, or 340,000 g/mol), and the pH value (4, 7, and 11) influenced the resulting wetting behavior of the PVFA-co-PVAm-modified wood veneer surface. Thus, the hydrophobizing effect of the PVFA-co-PVAm was clearly detectable because the contact angle with water was considerably increased up to 116° by adsorption of PVFA-co-PVAm 9095 at pH 11. The adsorbed amount of PVFA-co-PVAm was determined by energy-dispersive X-ray (EDX) spectroscopy and X-ray photoelectron spectroscopy (XPS). The PVFA-co-PVAm-coated wood veneers were consolidated with bio-PE in a hot press process. The modified composite materials showed remarkably improved Young’s moduli (552 MPa) and tensile strengths (4.5 MPa) compared to former composite materials produced without PVFA-co-PVAm modification.

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