Removal properties of arsenic compounds with synthetic hydrotalcite compounds

2005 ◽  
Vol 5 (5) ◽  
pp. 75-81 ◽  
Author(s):  
Y. Kiso ◽  
Y. J. Jung ◽  
T. Yamada ◽  
M. Nagai ◽  
K. S. Min
Keyword(s):  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Inorganic Arsenic ◽  
Underground Water ◽  
Experimental Result ◽  
Maximum Adsorption Capacity ◽  
Arsenic Compounds ◽  
Adsorption Sites ◽  
Effects Of Ph ◽  
Very High

The contamination of underground water with inorganic arsenic compounds has caused serious problems, particularly in developing countries. For water containing low-level arsenic compounds, an adsorption process may be more effective than other processes such as RO membrane and precipitation. In this study, the removal performance for arsenic compounds was examined with synthetic hydrotalcite (HTAL) compounds as an adsorbent process from the following viewpoints: the adsorption capacity, adsorption isotherm, the effects of pH and co-existing anions. The HTAL-Cl, which contains Cl− ions as an intercalate, showed very high adsorption capacity in the neutral pH region. The maximum adsorption capacity was 105 mg-As(V) g−1. The adsorption isotherm was approximated by the following modified Langmuir equation:The equation suggests that one mol of As(V) occupies two adsorption sites of HTAL-Cl, and the experimental result indicated that 2.64 mol of Cl− ions in the HTAL-Cl were substituted with one mol of As(V). The interfering effects of co-existing anions were relatively low, and the magnitude of the effects was observed in the order of HCO3− > HPO42− > SO42− > Cl−.

Removal of hexavalent chromium from aqueous solution using exfoliated polyaniline/montmorillonite composite

2014 ◽  
Vol 70 (4) ◽  
pp. 678-684 ◽  
Author(s):  
Jun Chen ◽  
Xiaoqin Hong ◽  
Yongteng Zhao ◽  
Qianfeng Zhang
Keyword(s):  
Adsorption Capacity ◽  
Chemical Oxidation ◽  
Maximum Adsorption Capacity ◽  
Isothermal Model ◽  
Adsorption Characteristic ◽  
In Situ Chemical Oxidation ◽  
Acid Copolymer ◽  
Chemical Oxidation Polymerization ◽  
Effects Of Ph ◽  
Pseudo Second Order

Exfoliated polyaniline/montmorillonite (PANI/MMT) composites with nanosheet structure were successfully prepared by in situ chemical oxidation polymerization with MMT platelets as the scaffold. Amphoteric polymer, (2-methacryloyloxyethyl)trimethyl ammonium chloride and methacrylate acid copolymer, was used to modify montmorillonite and a large number of carboxylic acids were introduced on the surface of the clay platelets, which can be used as a dopant of PANI and play a ‘bridge’ role to combine PANI with clay. Adsorption experiments were carried out to study the effects of pH, contact time, Cr(VI) concentration, adsorbent dose and temperature. The adsorption of Cr(VI) on the PANI/MMT was highly pH dependent and the adsorption kinetics followed a pseudo-second-order model. The Langmuir isothermal model described the adsorption isotherm data well and the maximum adsorption capacity increased with the increase in temperature. Thermodynamic investigation indicated that the adsorption process is spontaneous, endothermic and marked with an increase in randomness at the adsorbent – liquid interface. The maximum adsorption capacity of the PANI/MMT composites for Cr(VI) was 308.6 mg/g at 25 °C. The excellent adsorption characteristic of exfoliated PANI/MMT composites will render it a highly efficient and economically viable adsorbent for Cr(VI) removal.

Preparation of Graphene Oxide Modified Rice Husk for Cr(VI) Removal

2019 ◽  
Vol 19 (11) ◽  
pp. 7035-7043 ◽  
Author(s):  
Tong Ouyang ◽  
Jidan Tang ◽  
Fang Liu ◽  
Chang-Tang Chang
Keyword(s):  
Graphene Oxide ◽  
Adsorption Capacity ◽  
Rice Husk ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Adsorption Sites ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Alkaline Conditions ◽  
Rice Husk Biochar

The objective of this paper is to study the removal of Cr(VI) in aqueous solution by using a new graphene oxide-coated rice husk biochar composite (GO-RHB). GO-RHB is a synthetic material having a porous structure with lots of oxygen-containing functional groups and a large surface area that provide effective adsorption sites. Experiments showed that GO-RHB had higher adsorption capacity under acidic than under alkaline conditions. At pH of 2, GO-RHB has the maximum adsorption capacity(48.8 mg g−1). Equilibrium data obtained by fitting with the Langmuir and Freundlich models indicate that the reaction process was monolayer adsorption. The adsorption of Cr(VI) followed the pseudo-second-order kinetic model that illustrates chemical adsorption. Intraparticlediffusion studies further revealed that film diffusion was taking place. Moreover, the results of thermodynamics showed that the adsorption process was endothermic and spontaneous in nature. The removal mechanism of Cr(VI) was also explained in detail. The prepared adsorbent is highly efficient and might be useful than many other conventional adsorbent used for the removal of Cr(VI) from wastewater.

scholarly journals The Triple Mechanisms of Atenolol Adsorption on Ca-Montmorillonite: Implication in Pharmaceutical Wastewater Treatment

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2858 ◽  
Author(s):  
Po-Hsiang Chang ◽  
Wei-Teh Jiang ◽  
Binoy Sarkar ◽  
Wendong Wang ◽  
Zhaohui Li
Keyword(s):  
Adsorption Capacity ◽  
Clay Mineral ◽  
Basal Spacing ◽  
Maximum Adsorption Capacity ◽  
Pharmaceutical Wastewater ◽  
Absorption Bands ◽  
Adsorption Mechanisms ◽  
Adsorption Sites ◽  
Dioctahedral Smectite ◽  
Β Receptor

The adsorption of atenolol (AT) from aqueous solutions by Ca-montmorillonite (SAz-2) was investigated in batch studies under different physicochemical conditions. The AT existed in neutral un-dissociated form at pH 10, and was adsorbed on dioctahedral smectite (SAz-2) obeying the Langmuir isotherm with a maximum adsorption capacity of 330 mmol/kg. The kinetic adsorption suggested that both strong and weak adsorption sites existed on SAz-2 and participated in the adsorption mechanisms. The amount of exchangeable cations desorbed from SAz-2 during AT adsorption was linearly correlated with the amounts of adsorbed AT having slopes of 0.43, which implied that a cation exchange based adsorption mechanism was also in place. A comprehensive basal spacing change of SAz-2 was observed after AT adsorption on the clay mineral when tested with or without AT recrystallization. The intercalation of AT into the SAz-2 interlayers did not result in swelling due to the low adsorption capacity of the drug. Prominent interactions between the pharmaceutical molecule and SAz-2 were evidenced by apparent shifts of the infrared absorption bands after adsorption. The interlayer configurations and hydrogen bonding of AT on SAz-2 were also supported by infrared, X-ray diffraction and thermogravimetric analyses. This study suggested that SAz-2 is an excellent material to remove not only AT from pharmaceutical wastewater, but can potentially remove many other β-receptor blocker drugs. The results helped us to understand the possible interlayer configurations and adsorption mechanisms of the drugs on natural clay mineral based adsorbents.

Adsorption of chromium (VI) from aqueous solutions on activated carbon

1994 ◽  
Vol 30 (9) ◽  
pp. 191-197 ◽  
Author(s):  
R. Leyva Ramos ◽  
A. Juarez Martinez ◽  
R. M. Guerrero Coronado
Keyword(s):  
Activated Carbon ◽  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Ph Effect ◽  
Freundlich Isotherm ◽  
Maximum Adsorption Capacity ◽  
Experimental Adsorption ◽  
Ph Values ◽  
Chromium Vi ◽  
Adsorption Data

The adsorption isotherm of chromium (VI) on activated carbon was obtained in a batch adsorber. The experimental adsorption data were fitted reasonably well to the Freundlich isotherm. The effect of pH on the adsorption isotherm was investigated at pH values of 4, 6, 7, 8, 10 and 12. It was found that at pH < 6, Cr(VI) was adsorbed and reduced to Cr(III) by the catalytic action of the carbon and that at pH ≥ 12, Cr(VI) was not adsorbed on activated carbon. Maximum adsorption capacity was observed at pH 6 and the adsorption capacity was diminished about 17 times by increasing the pH from 6 to 10. The pH effect was attributed to the different complexes that Cr(VI) can form in aqueous solution. The adsorption isotherm was also affected by the temperature since the adsorption capacity was increased by raising the temperature from 25 to 40°C. It was concluded that Cr(VI) was adsorbed significantly on activated carbon at pH 6 and that the adsorption capacity was greatly dependent upon pH.

scholarly journals Effects of Cu(II) on the Adsorption Behaviors of Cr(III) and Cr(VI) onto Kaolin

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Juanjuan Liu ◽  
Xiaolong Wu ◽  
Yandi Hu ◽  
Chong Dai ◽  
Qin Peng ◽  
...  
Keyword(s):  
Distribution Coefficient ◽  
Adsorption Capacity ◽  
Removal Efficiency ◽  
Saturation Index ◽  
Surface Complexation ◽  
Maximum Adsorption Capacity ◽  
Positive Correlation ◽  
Adsorption Sites ◽  
Ph Values ◽  
Adsorption Behaviors

The adsorption of Cr(III) or Cr(VI) in the absence and presence of Cu(II) onto kaolin was investigated under pH 2.0–7.0. Results indicated that the adsorption rate was not necessarily proportional to the adsorption capacity. The solutions’ pH values played a key role in kaolin zeta potential(ζ), especially the hydrolysis behavior and saturation index of heavy metal ions. In the presence of Cu(II),qmixCr(III)reached the maximum adsorption capacity of 0.73 mg·g−1at pH 6.0, while the maximum adsorption capacity for the mixed Cr(VI) and Cu(II) system (qmixCr(VI)) was observed at pH 2.0 (0.38 mg·g−1). Comparing the adsorption behaviors and mechanisms, we found that kaolin prefers to adsorb hydrolyzed products of Cr(III) instead of Cr3+ion, while adsorption sites of kaolin surface were occupied primarily by Cu(II) through surface complexation, leading to Cu(II) inhibited Cr(VI) adsorption. Moreover, Cr(III) and Cr(VI) removal efficiency had a positive correlation with distribution coefficientKd. Cr(III) and Cr(VI) removal efficiency had a positive correlation with distribution coefficientKdand that of adsorption affinities of Cr(III) or Cr(VI) on kaolin was found to beKdCr(III) <KdCr(III)-Cu(II) andKdCr(VI) >KdCr(VI)-Cu(II).

Adsorption of cadmium(II) from aqueous solution onto activated carbon

1997 ◽  
Vol 35 (7) ◽  
pp. 205-211 ◽  
Author(s):  
R. Leyva-Ramos ◽  
J. R. Rangel-Mendez ◽  
J. Mendoza-Barron ◽  
L. Fuentes-Rubio ◽  
R. M. Guerrero-Coronado
Keyword(s):  
Activated Carbon ◽  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Freundlich Isotherm ◽  
Carbon Surface ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Ph Values ◽  
Average Percent Deviation ◽  
Initial Ph

The adsorption isotherm of cadmium on activated carbon was measured in a batch adsorber. Effects of temperature and solution pH on the adsorption isotherm were investigated by determining the adsorption isotherm at temperatures of 10, 25, and 40°C and at initial pH values from 2 to 8. Langmuir isotherm better fitted the experimental data since the average percent deviation was lower than with the Freundlich isotherm It was noticed that the amount of Cd2+ adsorbed was reduced about 3 times by increasing the temperature from 10 to 40°C. It was found that Cd2+ was not adsorbed on activated carbon at pH of 2 or lower and that Cd2+ was precipitated out as Cd(OH)2 at pH values above 9. Maximum adsorption capacity was observed at pH of 8 and the adsorption capacity was decreased about 12 times by reducing the initial pH from 8 to 3. According to the cadmium speciation diagram the predominant species below pH of 8 is Cd2+. Thus, cadmium was adsorbed on the activated carbon surface as Cd2+. It was concluded that the adsorption capacity is a strong function of pH and temperature.

scholarly journals Investigation of kinetics and adsorption isotherm for fluoride removal from aqueous solutions using mesoporous cerium–aluminum binary oxide nanomaterials

RSC Advances ◽  
2021 ◽  
Vol 11 (46) ◽  
pp. 28744-28760
Author(s):  
Rumman Zaidi ◽  
Saif Ullah Khan ◽  
I. H. Farooqi ◽  
Ameer Azam
Keyword(s):  
Adsorption Isotherm ◽  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Removal Efficiency ◽  
Small Dose ◽  
Binary Oxide ◽  
Fluoride Removal ◽  
Maximum Adsorption Capacity

Mesoporous Ce–Al binary oxide nanomaterials prepared with a surface area of 110.32 m2 g−1 showed defluoridation capacity at pH 2.4, exhibited maximum adsorption capacity of 384.6 mg g−1 and a removal efficiency of 91.5% at a small dose of nanoadsorbent.

scholarly journals Nanoarchitectonics for High Adsorption Capacity Carboxymethyl Cellulose Nanofibrils-Based Adsorbents for Efficient Cu2+ Removal

Nanomaterials ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 160
Author(s):  
Rongrong Si ◽  
Yehong Chen ◽  
Daiqi Wang ◽  
Dongmei Yu ◽  
Qijun Ding ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Carboxymethyl Cellulose ◽  
Cellulose Nanofibrils ◽  
Maximum Adsorption Capacity ◽  
Crosslinking Reaction ◽  
Carboxyl Content ◽  
Edta Solution ◽  
Effects Of Ph ◽  
Adsorption Desorption

In the present study, carboxymethyl cellulose nanofibrils (CMCNFs) with different carboxyl content (0.99–2.01 mmol/g) were prepared via controlling the ratio of monochloroacetic acid (MCA) and sodium hydroxide to Eucalyptus bleached pulp (EBP). CMCFs-PEI aerogels were obtained using the crosslinking reaction of polyethyleneimine (PEI) and CMCNFs with the aid of glutaraldehyde (GA). The effects of pH, contact time, temperature, and initial Cu2+ concentration on the Cu2+ removal performance of CMCNFs-PEI aerogels was highlighted. Experimental data showed that the maximum adsorption capacity of CMCNF30-PEI for Cu2+ was 380.03 ± 23 mg/g, and the adsorption results were consistent with Langmuir isotherm (R2 > 0.99). The theoretical maximum adsorption capacity was 616.48 mg/g. After being treated with 0.05 M EDTA solution, the aerogel retained an 85% removal performance after three adsorption–desorption cycles. X-ray photoelectron spectroscopy (XPS) results demonstrated that complexation was the main Cu2+ adsorption mechanism. The excellent Cu2+ adsorption capacity of CMCNFs-PEI aerogels provided another avenue for the utilization of cellulose nanofibrils in the wastewater treatment field.

Preparation and Chelating Properties of Polystyrene Modified Ethoxycarbonyl Thiourea Resin

2011 ◽  
Vol 239-242 ◽  
pp. 781-785 ◽  
Author(s):  
Shuai Wang ◽  
Hong Zhong ◽  
Liu Yin Xia ◽  
Zhong Nan Wang ◽  
Qian Zhang
Keyword(s):  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Maximum Adsorption Capacity ◽  
Polymer Grafting ◽  
Isotherm Equation ◽  
Adsorption Capacities ◽  
Adsorption Data ◽  
Separation Factors ◽  
Langmuir Isotherm Equation ◽  
Freundlich Adsorption Isotherm

A novel polystyrene modified ethoxycarbonyl thiourea resin(PSETU) was synthesized by polymer grafting of aminated polystyrene and ethoxycarbonyl isothiocyanate. The adsorption capacities of PSETU follow the order: Au(III) > Cu(II) > Zn(II) > Ni(II) > Fe(III) > Ca(II) ≈ Mg(II). The adsorption capacity for Au(III) increases with the increase of contact time, temperature and initial concentration of Au(III). The adsorption data fit Boyd’s diffusion equation of liquid film, Langmuir adsorption isotherm and Freundlich adsorption isotherm. The maximum adsorption capacity of PSETU calculated by Langmuir isotherm equation is 3.485 mmol/g, and the separation factors of PSETU for Au(III)-base metal ions are above 380. According to XPS results, the functional atoms of PSETU coordinate with Au(III) during the adsorption process.

scholarly journals Removal of Anionic and Cationic Dyes from Wastewater Using Activated Carbon from Palm Tree Fiber Waste

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 416
Author(s):  
Basma G. Alhogbi ◽  
Shoruq Altayeb ◽  
Effat. A. Bahaidarah ◽  
Mahmoud F. Zawrah
Keyword(s):  
Electron Microscopy ◽  
Activated Carbon ◽  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Chemical Activation ◽  
High Yield ◽  
Maximum Adsorption Capacity ◽  
Palm Tree ◽  
Fast Method ◽  
Adsorbent Dosage

This study focuses on using a facile method for the green preparation of activated carbon (AC) from palm tree fiber (PTF) waste. The synthesized cost-effective AC was investigated for the removal of an anionic dye (Congo red, CR) and a cationic dye (Rhodamine B, RhB) from wastewater. The morphological and structural characterization of the synthesized AC were performed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), surface area, Fourier transform infrared spectroscopy (FTIR), total pore volume, average pore diameter and pore size distribution, zeta potential, and zero-point charge. To investigate the adsorption efficiency, different parameters such as adsorbent dosage, solution pH, initial dye concentration, and duration were applied using the batch experiments. Various adsorption isotherm and kinetics models were applied to study the adsorption mechanism and dynamics. The results showed that chemical activation with a weak acid (H3PO4) at 400 °C for 30 min is a fast method for the activation of each precursor and produces a high yield. The result of analysis showed an increase in the adsorption capacity at pH 2. The maximum adsorption capacity was 9.79 and 26.58 mg g−1 at 30 min for CR dye and RhB dye, respectively. The optimum adsorbent dosage for the activated carbon from palm tree fiber (PTFAC) was 0.15 g with a high percentage removal of CR (98.24%) and RhB (99.86%) dyes. The adsorption isotherm and kinetic studies were found to be favorable and feasible for assessing the adsorption of dyes with the Langmuir model and pseudo-second-order reaction, respectively. In addition, the AC showed reusability up to five cycles. The results showed that the synthesized AC was environmentally friendly and successfully removed dyes from wastewater.

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