scholarly journals Removal of Cr(VI) from Aqueous Solution by Polypyrrole/Hollow Mesoporous Silica Particles

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 686 ◽  
Author(s):  
Linlin Du ◽  
Peng Gao ◽  
Yuanli Liu ◽  
Tsuyoshi Minami ◽  
Chuanbai Yu

The removal of Cr(VI) in wastewater plays an important role in human health and environment. In this work, polypyrrole/hollow mesoporous silica particle (PPy/HMSNs) adsorbents have been newly synthesized by in-situ polymerization, which prevent the aggregation of pyrrole in the process of polymerization and exhibit highly selective and powerful adsorption ability for Cr(VI). The adsorption process was in good agreement with the quasi-second-order kinetic model and the Langmuir isotherm model. And the maximum adsorption capacity of Cr(VI) was 322 mg/g at 25 °C. Moreover, the removal rate of Cr(VI) by PPy/HMSNs was ~100% in a number of binary systems, such as Cl−/Cr(VI), NO3−/Cr(VI), SO42−/Cr(VI), Zn2+/Cr(VI), Fe3+/Cr(VI), Sn4+/Cr(VI), and Cu2+/Cr(VI). Thus, the PPy/HMSNs adsorbents have great potential for the removal of Cr(VI) in wastewater.

2013 ◽  
Vol 750-752 ◽  
pp. 47-50
Author(s):  
Wen Juan He ◽  
Yu Feng He ◽  
Zhen Hua Zhang ◽  
Ju Hua Guo ◽  
Rong Min Wang

In this paper, a new kind of clay copolymer adsorbent, bentonite compositing with maleic anhydride (MAH)-acrylic acid (AA)-vinyl acetate (VAc) copolymer (NaB/PMAV) was prepared by in-situ polymerization. It was used as polymer adsorbent for removing Pb (II) ions in wastewater.. Under the optimal condition of adsorption, the removal rate reached to 94.4% and the adsorption capacity got to 235.9 mg/g. Adsorption dynamics were consistent with pseudo-second-order kinetic model and isotherm model can meet the Langmuir isotherm.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yige Guo ◽  
Bin Chen ◽  
Ying Zhao ◽  
Tianxue Yang

AbstractAntibiotics are emerging pollutants and increasingly present in aquaculture and industrial wastewater. Due to their impact on the environment and health, their removal has recently become a significant concern. In this investigation, we synthesized nano zero-valent iron-loaded magnetic mesoporous silica (Fe-MCM-41-A) via precipitation and applied the adsorption of oxytetracycline (OTC) from an aqueous solution. The effects of competing ions such as Na+, Ca2+ and Cu2+ on the adsorption process under different pH conditions were studied in depth to providing a theoretical basis for the application of nanomaterials. The characterization of the obtained material through transmission electron microscopy demonstrates that the adsorbent possesses hexagonal channels, which facilitate mass transfer during adsorption. The loaded zero-valent iron made the magnetic, and was thus separated under an applied magnetic field. The adsorption of OTC onto Fe-MCM-41-A is rapid and obeys the pseudo-second-order kinetic model, and the maximum adsorption capacity of OTC is 625.90 mg g−1. The reaction between OTC and Fe-MCM-41-A was inner complexation and was less affected by the Na+. The effect of Ca2+ on the adsorption was small under acidic and neutral conditions. However, the promotion effect of Ca2+ increased by the increase of pH. Cu2+ decreased the removal efficiencies continuously and the inhibitory effects decrease varied with the increase of pH. We propose that surface complexing, ion-exchange, cationic π-bonding, hydrogen bonding, and hydrophobicity are responsible for the adsorption of OTC onto Fe-MCM-41-A.


2009 ◽  
Vol 610-613 ◽  
pp. 65-68 ◽  
Author(s):  
Xue Gang Luo ◽  
Feng Liu ◽  
Xiao Yan Lin

Konjac glucomannan (KGM) was converted into water insoluble konjac glucomannan (WIKGM) by treating with NaOH through completely deacetylated reaction. Adsorption study was carried out for the adsorption of Pb2+ from aqueous solution using water insoluble konjac glucomannan. The influences of pH, contact time, temperature and initial Pb2+ concentration on the absorbent were studied. Results of kinetic data showed that the Pb2+ adsorption rate was fast and good correlation coefficients were obtained for the pseudo second-order kinetic model. The equilibrium process was described well by the Langmuir isotherm model with maximum adsorption capacity of 9.18 mg/g on WIKGM at 25°C.


2014 ◽  
Vol 71 (2) ◽  
pp. 174-182 ◽  
Author(s):  
Ruihua Huang ◽  
Qian Liu ◽  
Lujie Zhang ◽  
Bingchao Yang

A kind of biocomposite was prepared by the intercalation of chitosan in bentonite and the cross-linking reaction of chitosan with glutaraldehyde, which was referred to as cross-linked chitosan/bentonite (CCS/BT) composite. Adsorptive removal of methyl orange (MO) from aqueous solutions was investigated by batch method. The adsorption of MO onto CCS/BT composite was affected by the ratio of chitosan to BT and contact time. pH value had only a minor impact on MO adsorption in a wide pH range. Adsorption kinetics was mainly controlled by the pseudo-second-order kinetic model. The adsorption of MO onto CCS/BT composite followed the Langmuir isotherm model, and the maximum adsorption capacity of CCS/BT composite calculated by the Langmuir model was 224.8 mg/g. Experimental results indicated that this adsorbent had a potential for the removal of MO from aqueous solutions.


2017 ◽  
Vol 76 (6) ◽  
pp. 1565-1573 ◽  
Author(s):  
Jun Liu ◽  
Siying Xia ◽  
Xiaomeng Lü ◽  
Hongxiang Shen

Phosphorus flame retardant tricresyl phosphate (TCP) adsorption on graphene nanomaterials from aqueous solutions was explored using batch and column modes. Comparative studies were performed regarding the kinetics and equilibrium of TCP adsorption on graphene oxide (GO) and graphene (G) in batch mode. The adsorption kinetics exhibited a rapid TCP uptake, and experimental data were well described by the pseudo-second-order kinetic model. Adsorption isotherm data of TCP on the two adsorbents displayed an improved TCP removal performance with increasing temperature at pH 5, while experimental data were well described by the Langmuir isotherm model with a maximum adsorption capacity of 87.7 mg·g−1 for G, and 30.7 mg·g−1 for GO) at 303 K. The thermodynamic parameters show that the adsorption reaction is a spontaneous and endothermic process. In addition, dynamic adsorption of TCP in a fixed G column confirmed a faster approach to breakthrough at high flow rate, high influent TCP concentration, and low filling height of adsorbent. Breakthrough data were successfully described by the Thomas and Yoon-Nelson models.


2018 ◽  
Vol 36 (3-4) ◽  
pp. 1160-1177 ◽  
Author(s):  
Liyun Yang ◽  
Xiaoming Qian ◽  
Zhi Wang ◽  
Yuan Li ◽  
Hao Bai ◽  
...  

This study investigates the removal effectiveness and characteristics of phenanthrene and naphthalene using low-cost steel slag with batch experiments. The adsorption characteristics of steel slag were measured and analysed using X-ray fluorescence, X-ray diffraction, and Fourier transform infrared spectroscopy. The batch experiments investigated the effect of the time gradient, pH, and steel slag dosage gradient on the adsorption of the steel slag. The results show that with time and dosage of steel slag increased, the adsorption capacity of phenanthrene and naphthalene increased and gradually became balanced, but pH had no obvious effect on the adsorption of phenanthrene and naphthalene. The Langmuir isotherm model best describes the phenanthrene and naphthalene removal by the steel slag, which shows the adsorption occurring in a monolayer. The maximum adsorption capacity of the steel slag to phenanthrene and naphthalene is 0.043 and 0.041 mg/g, respectively. A pseudo-first-order kinetic model can better represent the adsorption of phenanthrene and naphthalene by steel slag. The research demonstrates that the steel slag has a certain adsorption capacity for phenanthrene and naphthalene.


Author(s):  
Ayben Polat ◽  
Sukru Aslan

The sorption of Cu2+ ions from aqueous solutions by eggshell was investigated in a batch experimental system with respect to the temperature, initial Cu2+ concentrations, pH, and biosorbent doses. The adsorption equilibrium was well described by the Langmuir isotherm model with the maximum adsorption capacity of 5.05 mg Cu2+/g eggshell at 25 °C. The value of qe increased with increasing the temperature while also increases the release of Ca2+ and HCO−3 ions from the eggshell. The highest sorption of Cu onto the waste eggshell was determined at the initial pH value of 4.0. The results confirming that the adsorption reaction of Cu2+ on the eggshell was thought to be endothermic. A comparison of the kinetic models such as pseudo first and second-order kinetics, intraparticle diffusion, and Elovich on the sorption rate demonstrated that the system was best described by the pseudo second-order kinetic model.


2018 ◽  
Vol 768 ◽  
pp. 231-235
Author(s):  
Ya Shen ◽  
Yin Wang ◽  
Yu Feng He ◽  
Rong Min Wang

Dyes have made a great contribution to the progress of this beautiful and bright world,but a large amount of wastes containing dyes have been discharged into the receiving aquatic environment. In this paper, a loess composited polymer adsorbent, poly (methacrylic acid)-grafted chitosan/Loess composite (PMAA-CS/ LC), was applied to remove methylene blue (MB). It was found that the removal rate of MB reached to 98.6% under the optimal condition of adsorption. Adsorption dynamics were consistent with pseudo-second-order kinetic model and isotherm model can meet the Langmuir isotherm model.


2021 ◽  
Author(s):  
Xin Ye ◽  
Sisi Shang ◽  
Yifan Zhao ◽  
Sheng Cui ◽  
Ya Zhong ◽  
...  

Abstract The modified montmorillonite(MMT) has a two-dimensional stable and ordered lamellar structure. The addition of chitosan(CS) cross-links the two-dimensional sheets to build a three-dimensional network structure with a high specific surface area. We have prepared the best MMT-based water treatment materials that have been reported. This new type of aerogel can efficiently adsorb heavy metal ions in wastewater. The structure and performance of the composite material were characterized in this article. Besides, the adsorption kinetics, adsorption thermodynamics, pH influence, and recycling performance are all focused on. The adsorption equilibrium time of CS-MMT2 is 50 min. The removal rate of Cu2+ is as high as 98.21%. The maximum adsorption capacity is 86.95 mg/g. The adsorption process of Cu2+ by CS-MMT composite aerogel conforms to the quasi-second-order kinetic model and the Langrangian adsorption isotherm. After three cycles, the removal rate of Cu2+ by CS-MMT2 remained above 80%. This article also involves the discussion of the material's adsorption mechanism for Cu2+. This is a kind of environmentally friendly material that can be mass-produced, cheap, efficient, and excellent, which is of great significance to the development of environmental protection.


Separations ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 224
Author(s):  
Ismat H. Ali ◽  
Mutasem Z. Bani-Fwaz ◽  
Adel A. El-Zahhar ◽  
Riadh Marzouki ◽  
Mosbah Jemmali ◽  
...  

In this study, a gum Arabic-magnetite nanocomposite (GA/MNPs) was synthesized using the solution method. The prepared nanocomposite was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and thermogravimetric analysis (TGA). The prepared composite was evaluated for the adsorption of lead(II) ions from aqueous solutions. The controlling factors such as pH, contact time, adsorbent dose, initial ion concentration, and temperature were investigated. The optimum adsorption conditions were found to be 0.3 g/50 mL, pH = 6.00, and contact time of 30 min. The experimental data well fitted the pseudo-second-order kinetic model and the Langmuir isotherm model. The maximum adsorption capacity was determined as 50.5 mg/g. Thermodynamic parameters were calculated postulating an endothermic and spontaneous process and a physio-sorption pathway.


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