scholarly journals Self-Supported Reduced Graphene Oxide Membrane and Its Cu2+ Adsorption Capability

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 146
Author(s):  
Yangjinghua Yu ◽  
Zhong Wang ◽  
Runjun Sun ◽  
Zhihua Chen ◽  
Meicheng Liu ◽  
...  

Graphene stratiform membrane materials have been recently applied to heavy metal removal in aqueous systems via adsorption due to their high mechanical strength, chemical stability, and other properties. We applied reduced graphene oxide (rGO) alone as an adsorbent to remove heavy metal ions from wastewater. Self-supported rGO membrane was prepared using a green reduction method with sodium hydrosulfite. We used the Raman spectra to observe the structure of the rGO membrane. The morphology of the self-supported membrane was measured by a scanning electron microscope. The Cu2+ adsorption performance was measured in terms of pH, reaction time, metal ion concentration, and temperature. The maximum Cu2+ adsorption capacity of the rGO membrane was found to be 149.25 mg/g. The adsorption process followed a pseudo-second-order kinetic model, and adsorption isotherms were simulated by the Freundlich model.

2019 ◽  
Vol 145 (9) ◽  
pp. 04019049 ◽  
Author(s):  
Murugan Muthu ◽  
Krishnan Chandrasekharapuram Ramakrishnan ◽  
Manu Santhanam ◽  
Murali Rangarajan ◽  
Mathava Kumar

2021 ◽  
Vol 287 ◽  
pp. 04006
Author(s):  
Patrick Tan Peng Jun ◽  
Wan Nur Aisyah Wan Osman ◽  
Shafirah Samsuri ◽  
Juniza Md Saad ◽  
Muhamad Fadli Samsudin ◽  
...  

Recent studies have shown great interest toward heavy metal removal due to its hazardous and non-biodegradable properties. Many approaches have been used for this purpose and one of them is adsorption. In this study, several experiments were carried out to investigate the feasibility of factory tea waste as a biosorbent in a fixed-bed adsorption column for heavy metal removal (zinc and copper) in wastewater. The results highlighted that zinc has better performance compared to copper in terms of the effect of initial ion concentration, pH value, and the mixed ions with respect to the removal efficiency. Zinc showed higher removal efficiency and adsorption capacity at the initial metal ion concentration of 200 mg/L, which are 99.21% and 39.68 mg/mg compared to copper. Meanwhile, for the effect of pH values and mixed ion concentration, zinc also showed slightly higher removal efficiency which are 99.91% and 98.47%, respectively compared to copper. However, both zinc and copper showed a better fit to the Langmuir isotherm. The factory tea waste was characterized using Micromeritics ASAP 2020 instrument and results showed that the factory tea waste biosorbent consists of mesopores with the diameter and width of 4.85205 and 2.546985 nm, respectively.


2002 ◽  
Vol 20 (7) ◽  
pp. 607-617 ◽  
Author(s):  
Adil Denizli ◽  
Bora Garipcan ◽  
Sibel Emir ◽  
Süleyman Patir ◽  
Ridvan Say

Details of the adsorption performance of poly(2-hydroxyethylmethacrylate–methacrylamidocysteine) [p(HEMA–MAC)] beads towards the removal of heavy metal ions from aqueous solution were studied. The metal-complexing ligand and/or co-monomer MAC was newly synthesized from methylacrylochloride and cysteine. Spherical beads of average size 150–200 mm were obtained by the radical suspension polymerization of MAC and HEMA conducted in an aqueous dispersion. The p(HEMA–MAC) beads obtained had a specific surface area of 18.9 m2/g. p(HEMA–MAC) beads were characterized by swelling studies, FT-IR spectroscopy and elemental analysis. Such beads with a swelling ratio of 72%, and containing 3.9 mmol MAC/g, were used for heavy metal removal studies. The adsorption capacities of the beads for selected metal ions, i.e. CdII, AsIII, CrIII, HgII and PbII, were investigated in aqueous media containing different amounts of these ions (10–750 mg/l) and at different pH values (3.0–7.0). The adsorption rate was fast in all cases. The maximum adsorption capacities of the p(HEMA–MAC) beads were 1058.2 mg/g for CdII, 123.4 mg/g for AsIII, 199.6 mg/g for CrIII, 639.1 mg/g for PbII and 1018.6 mg/g for HgII. On a molar basis, the following affinity order was observed: CdII > HgII > CrIII > PbII >AsIII. The adsorption capacity of the MAC-incorporated beads was affected significantly by the pH value of the aqueous medium. The adsorption of heavy metal ions from artificial wastewater was also studied. In this case, the adsorption capacities were 52.2 mg/g for CdII, 23.1 mg/g for CrIII, 83.4 mg/g for HgII, 62.6 mg/g for PbII and 11.1 mg/g for AsIII at an initial metal ion concentration of 0.5 mmol/l. The chelating beads could be regenerated easily with a higher effectiveness by 0.1 M HNO3. These features make p(HEMA–MAC) beads potential candidates for heavy metal ion removal at high capacity.


2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Soyeon Park ◽  
Allan Gomez-Flores ◽  
Yong Sik Chung ◽  
Hyunjung Kim

Hydroxyapatite (HAp)/chitosan composites were prepared by a coprecipitation method, dropping a mixture of chitosan solution and phosphoric acid solution into a calcium hydroxide solution. Using the HAp/chitosan composites prepared, HAp/chitosan hybrid fibers with various HAp contents were prepared by a wet spinning method. X-ray diffraction and scanning electron microscopy analyses revealed that HAp particles were coated onto the surface of the fiber, and the surface roughness increased with increasing the HAp contents in the fiber. In order to evaluate the heavy metal removal characteristics of the HAp/chitosan hybrid fiber, adsorption tests were conducted and the results were compared with those of bare chitosan fibers. The results showed better performance in heavy metal ion removal for the HAp/chitosan hybrid fiber than the chitosan fiber. As the HAp content in the hybrid fiber increased, the removal efficiency of heavy metal ions also increased due to the increase of the specific surface area of the HAp/chitosan hybrid fiber. Adsorption kinetic and isotherm tests revealed that Pb2+and Cd2+adsorption to the hybrid fiber follows pseudo-second-order kinetic and Langmuir-type adsorption, respectively.


2020 ◽  
Vol 81 (10) ◽  
pp. 2163-2175 ◽  
Author(s):  
Fang Yuan ◽  
Lingzhi Yue ◽  
Han Zhao ◽  
Huifang Wu

Abstract In this paper, a study on the removal of imitated polystyrene (PS) microplastics in water was carried out based on the adsorption capacity of three-dimensional reduced graphene oxide (3D RGO). Scanning electron microscopy and X-ray diffractometry characterization showed that the freeze-dried 3D RGO formed a distinct porous spatial structure. Different experimental parameters, such as pH, ion concentration (C0), contact time (t), and temperature (T), were studied to investigate the PS microplastic adsorption performance of 3D RGO. The adsorption mechanism was mainly attributed to the strong π–π interaction between the carbon ring of 3D RGO and the benzene ring of PS microplastics. Sorption kinetic and isothermal data were obtained by the well-fitted Langmuir adsorption isotherm model and pseudo-second-order kinetic model. Furthermore, the result of thermodynamic analysis showed that the adsorption of PS microplastics was a spontaneous endothermic process. Under the optimal conditions of pH = 6, C0 = 600 mg/L, t = 120 min, and T = 26 °C, the maximum adsorption capacity of the prepared 3D RGO on PS microplastics was 617.28 mg/g. Furthermore, this method exhibited good feasibility in tap water and lake water.


2021 ◽  
Vol 303 ◽  
pp. 124460
Author(s):  
Fengming Yang ◽  
Xin Zhou ◽  
Fangjie Pang ◽  
Weijie Wang ◽  
Wenlong Wang ◽  
...  

2019 ◽  
Vol 55 (55) ◽  
pp. 7883-7898 ◽  
Author(s):  
Lixi Chen ◽  
Yimin Cai ◽  
Wen Feng ◽  
Lihua Yuan

This feature article reviews the development of functionalized pillararenes as supramolecular materials for lanthanide and actinide separation and heavy metal removal.


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