The effect of pH on the properties of 3D welan gum–graphene oxide composite hydrogels and their excellent adsorption capacity

RSC Advances ◽  
2016 ◽  
Vol 6 (97) ◽  
pp. 94373-94381 ◽  
Author(s):  
Jianmei Jiao ◽  
Xia Xin ◽  
Jinglin Shen ◽  
Zhaohua Song ◽  
Zengchun Xie ◽  
...  

The effect of pH on welan gum hydrogel for dye adsorption and swelling ratio.

RSC Advances ◽  
2015 ◽  
Vol 5 (92) ◽  
pp. 75589-75599 ◽  
Author(s):  
Menghong Yu ◽  
Aixin Song ◽  
Guiying Xu ◽  
Xia Xin ◽  
Jinglin Shen ◽  
...  

In this article, welan gum-graphene oxide (GO) composite hydrogels were prepared by simple self-assembly of both components in aqueous media and the effects of GO on the gelation of welan gum were systematically studied.


2020 ◽  
Vol 77 (12) ◽  
pp. 6609-6623 ◽  
Author(s):  
Daijun Xiao ◽  
Minghong He ◽  
Yulan Liu ◽  
Lijun Xiong ◽  
Qiao Zhang ◽  
...  

2021 ◽  
Vol 10 (1) ◽  
pp. 59-66
Author(s):  
Son Le Lam ◽  
Phu Nguyen Vinh ◽  
Hieu Le Trung ◽  
Tan Le Thua ◽  
Nhan Dang Thi Thanh ◽  
...  

Glucomannan/graphene oxide (GM/GO) hydrogel was synthesized by using calcium hydroxide as the crosslinker. The synthesized material was characterized by using IR, XRD, SEM, EDX and RAMAN technology. The composite hydrogel was used for removal of organic dyes from aqueous solution. The results showed that the GM/GO hydrogel had a porous structure and a high adsorption capacity toward methylene blue (MB). The pseudo-second-order kinetic model could fit the rate equation of MB adsorption onto the GM/GO hydrogel. The adsorption of MB onto GM/GO hydrogel was a spontaneous process. In addition, the equilibrium adsorption isotherm data indicated that equilibrium data were fitted to the Langmuir isotherm and the maximum dye adsorption capacity was 198,69 mg.g-1. Moreover, the hydrogel was stable and easily recovered and adsorption capacity was around 97% of the initial saturation adsorption capacity after being used five times.


2020 ◽  
Vol 7 (10) ◽  
pp. 200857 ◽  
Author(s):  
Junhong Tao ◽  
Jie Yang ◽  
Chengxiao Ma ◽  
Junfeng Li ◽  
Keqing Du ◽  
...  

Residual antibiotics in water are often persistent organic pollutants. The purpose of this study was to prepare a cellulose nanocrystals/graphene oxide composite (CNCs-GO) with a three-dimensional structure for the removal of the antibiotic levofloxacin hydrochloride (Levo-HCl) in water by adsorption. The scanning electron microscope, Fourier transform infrared (FT-IR), energy-dispersive spectroscopy, X-ray photoelectron spectroscopy and other characterization methods were used to study the physical structure and chemical properties of the CNCs-GO. The three-dimensional structure of the composite material rendered a high surface area and electrostatic attraction, resulting in increased adsorption capacity of the CNCs-GO for Levo-HCl. Based on the Box–Behnken design, the effects of different factors on the removal of Levo-HCl by the CNCs-GO were explored. The composite material exhibited good antibiotic adsorption capacity, with a removal percentage exceeding 80.1% at an optimal pH of 4, the adsorbent dosage of 1.0 g l −1 , initial pollutant concentration of 10.0 mg l −1 and contact time of 4 h. The adsorption isotherm was well fitted by the Sips model, and kinetics studies demonstrated that the adsorption process conformed to a quasi-second-order kinetics model. Consequently, the as-synthesized CNCs-GO demonstrates good potential for the effective removal of antibiotics such as levofloxacin hydrochloride from aqueous media.


2017 ◽  
Vol 727 ◽  
pp. 859-865 ◽  
Author(s):  
Yi Wei Zheng ◽  
Wen Wen Tao ◽  
Gui Fang Zhang ◽  
Chao Lv ◽  
Yi Ping Zhao ◽  
...  

Polyacrylic acid/attapulgite (PAA/ATP) composite hydrogels used for removal of heavy metal ions from aqueous solution was synthesized via radical polymerization with acrylic acid (AA) and attapulgite (ATP) modified by hydrochloric acid as adsorbent. Chemical composition of the modified ATP was characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) and the morphology of the PAA/ATP hydrogels was characterized by scanning electron microscope (SEM), respectively. The swelling ratio, pH-sensitivity and adsorption performance of Ni (II) ions of the composite hydrogels were studied. The results showed the swelling ratio of the PAA/ATP composite hydrogels was higher than that of PAA hydrogels and the composite hydrogels displayed sensitivity to pH values with a sharp increase of swelling ratio when the pH values increased from 4 to 6. Comparing with PAA hydrogels, the composite hydrogels obtained a larger adsorption capacity of Ni (II) ions, the average adsorption capacity could reach 72.8 mg/g and adsorption ratio could reach 84%.


2015 ◽  
Vol 51 (42) ◽  
pp. 8876-8879 ◽  
Author(s):  
Yunki Lee ◽  
Jin Woo Bae ◽  
Thai Thanh Hoang Thi ◽  
Kyung Min Park ◽  
Ki Dong Park

Graphene-based nanomaterials with different oxidation degrees were incorporated into Tetronic–tyramine (Tet–TA) hydrogels via enzymatic cross-linking.


Soft Matter ◽  
2012 ◽  
Vol 8 (6) ◽  
pp. 1831-1836 ◽  
Author(s):  
Jianfeng Shen ◽  
Bo Yan ◽  
Tie Li ◽  
Yu Long ◽  
Na Li ◽  
...  

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