scholarly journals Study on Adsorption Properties of Modified Corn Cob Activated Carbon for Mercury Ion

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4483
Author(s):  
Yuyingnan Liu ◽  
Xinrui Xu ◽  
Bin Qu ◽  
Xiaofeng Liu ◽  
Weiming Yi ◽  
...  

In this study, corn cob was used as raw material and modified methods employing KOH and KMnO4 were used to prepare activated carbon with high adsorption capacity for mercury ions. Experiments on the effects of different influencing factors on the adsorption of mercury ions were undertaken. The results showed that when modified with KOH, the optimal adsorption time was 120 min, the optimum pH was 4; when modified with KMnO4, the optimal adsorption time was 60 min, the optimal pH was 3, and the optimal amount of adsorbent and the initial concentration were both 0.40 g/L and 100 mg/L under both modified conditions. The adsorption process conforms to the pseudo-second-order kinetic model and Langmuir model. Scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Zeta potential characterization results showed that the adsorption process is mainly physical adsorption, surface complexation and ion exchange.

2017 ◽  
Vol 8 (3) ◽  
pp. 350-359 ◽  
Author(s):  
Danyang Yin ◽  
Zhengwen Xu ◽  
Jing Shi ◽  
Lili Shen ◽  
Zexiang He

Abstract In this study, schorl was used as an effective adsorbent for ciprofloxacin removal from wastewater. The adsorption performance, mechanism and effect of metal ion on sorption were investigated. Adsorption capacity reached a maximum (8.49 mg/g) when the pH value was 5.5. The pseudo-second-order kinetic model and Freundlich model could better describe the experimental data. The negative ΔH (–22.96 KJ/mol) value showed that the adsorption process was exothermic. The results also indicated physical adsorption existed on the adsorption process, which was in agreement with the analysis of X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy. The desorption rate could reach 94%, which suggested that schorl had a good desorption and regeneration performance. Coexisting ions, such as Cu2+ and Al3+, could obviously inhibit adsorption, and the inhibition from Al3+ was significantly higher than that from Cu2+. However, the additional Zn2+ could slightly promote the adsorption.


Author(s):  
Xiaorong Kang ◽  
Yali Liu ◽  
Can Yang ◽  
Han Cheng

Abstract Dewatered municipal sludge was used as raw material to prepare activated carbon (SAC), and the SAC was modified by walnut shell and nano-titanium dioxide (MSAC). The results showed that the MSAC had a higher specific surface area (SBET) (279.147 m2/g) and total pore volume (VT) (0.324 cm3/g) than the SAC. Simultaneously, the functional groups such as C-O, C = O, and Ti-O-Ti on the surface of MSAC were enhanced due to modification. These physicochemical properties provided prerequisites for the diffusion and degradation of pollutants in MSAC. Furthermore, the MSAC was applied to adsorb amoxicillin (AMX) from aqueous solution, in batch experiments, the maximum removal rate (88.19%) was observed at an initial AMX concentration of 30 mg/L, MSAC dosage of 5.0 g/L, pH of 8, contact time of 180 min, and temperature of 25 °C. In addition, the adsorption process was well described by the Freundlich isotherm model and pseudo-second-order kinetic model, indicating that the adsorption of AMX onto MSAC was dominated by multilayer chemisorption. Also, the adsorption thermodynamics suggested that the adsorption process of AMX onto MSAC was endothermic, feasible and spontaneous.


2012 ◽  
Vol 550-553 ◽  
pp. 2190-2193
Author(s):  
Xiao Yan Tan ◽  
Fang Zhao ◽  
Rui Zhi Wen ◽  
Yu Dai

Commercially available coal-based activated carbon was treated with different concentration of nitric acid. The resultant samples were used to adsorb lead from aqueous solution. N2 adsorption, Boehm titration, point of zero charge (pHPZC) and X-ray photoelectron spectroscopy (XPS) were used to characterize the samples. Acidic pH is favorable for Pb(Ⅱ) adsorption. The acidic groups increase significantly with the increment of the concentration of nitric acid during the treatment. The carboxylic groups of surface carbon play an important role in the adsorption process.


Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 768
Author(s):  
Jiawei Zhou ◽  
Liming Yao ◽  
Yunfeng Wang ◽  
Weiqi Zhao ◽  
Jiahui Gu

Iron tailings can be used as adsorbents to effectively remove graphene oxide (GO) in aqueous solutions. Experimental data show that pH, iron tailing quality, GO concentration and temperature have significant effects on the removal of GO, the adsorption of the tail involves a single layer adsorbed Langmuir model with exothermic reaction, and it compliance with the proposed dynamics model meets the requirements, the adsorption process is a spontaneous physical adsorption process. Combining scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) to analyze the iron tail according to the mechanisms of ore adsorption of GO, it was concluded that iron tailings might be a very promising material to effectively remove GO in aqueous solutions. The results of this research provide key information for the transportation and potential fate of GO in the natural environment.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
José María Rivera ◽  
Susana Rincón ◽  
Cherif Ben Youssef ◽  
Alejandro Zepeda

Mesoporous metal-organic framework-5 (MOF-5), with the composition Zn4O(BDC)3, showed a high capacity for the adsorptive removal of Pb(II) from 100% aqueous media. After the adsorption process, changes in both morphology and composition were detected using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray (EDX) system, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) analysis. The experimental evidence showed that Zn(II) liberation from MOF-5 structure was provoked by the water effect demonstrating that Pb(II) removal is not due to ionic exchange with Zn. A kinetic study showed that Pb(II) removal was carried out in 30 min with a behavior of pseudo-second-order kinetic model. The experimental data on Pb(II) adsorption were adequately fit by both the Langmuir and BET isotherm models with maximum adsorption capacities of 658.5 and 412.7 mg/g, respectively, at pH 5 and 45°C. The results of this work demonstrate that the use of MOF-5 has great potential for applications in environmental protection, especially regarding the removal of the lead present in industrial wastewaters and tap waters.


2018 ◽  
Vol 71 (3) ◽  
pp. 170 ◽  
Author(s):  
Xuejia Zhan ◽  
Guangzhi Hu ◽  
Thomas Wagberg ◽  
Dongwei Zhang ◽  
Pei Zhou

A novel aptasensor based on a tetracycline (TET) aptamer immobilized by physical adsorption on an ordered mesoporous carbon–Fe3O4 (OMC-Fe3O4)-modified screen-printed electrode surface was successfully fabricated. OMC-Fe3O4 was characterized by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The modification procedure of the aptasensor was characterized by cyclic voltammetry. Interaction between the TET aptamer and target was determined by differential pulse voltammetry. Under optimal conditions, the proposed aptasensor exhibited good electrochemical sensitivity to TET in a concentration range of 5 nM to 10 μM, with a detection limit of 0.8 nM (S/N = 3). This aptasensor exhibited satisfactory specificity, reproducibility, and stability.


2021 ◽  
Vol 13 (3) ◽  
pp. 371-380
Author(s):  
Yongjun Wu ◽  
Nina Xie ◽  
Lu Yu

A novel Ag–Si–TiO2 composite was prepared via sol–gel method for removing residual formaldehyde in shiitake mushroom. The structure of Ag–Si–TiO2 composite was characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses. Ultraviolet-visible absorption spectroscopy (UV-Vis) and N2 adsorption-desorption tests showed that Ag and Si co-doped decreased the band gap, the Brunauer-Emmett-Teller (BET) specific surface area of the samples increased and the recombination probability of electron-hole pairs (e--h+) reduced. Effect on removal rate of formaldehyde with different Ag-Si co-doped content, formaldehyde concentration and solution pH were investigated, and the results showed that 6.0 wt%Ag-3.0 wt%Si-TiO2 samples had an optimum catalytic performance, and the degradation efficiency reached 96.6% after 40 W 365 nm UV lamp irradiation for 360 min. The kinetics of formaldehyde degradation by Ag–Si–TiO2 composite photocatalyst could be described by Langmuir-Hinshelwood first-order kinetic model.


Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 926
Author(s):  
Shamim Ahmed Hira ◽  
Mohammad Yusuf ◽  
Dicky Annas ◽  
Hu Shi Hui ◽  
Kang Hyun Park

Activated carbon (AC) was fabricated from carrot waste using ZnCl2 as the activating agent and calcined at 700 °C for 2 h in a tube furnace. The as-synthesized AC was characterized using Fourier-transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analysis; the results revealed that it exhibited a high specific surface area and high porosity. Moreover, this material displayed superior catalytic activity for the degradation of toxic Rhodamine B (RhB) dye. Rate constant for the degradation of RhB was ascertained at different experimental conditions. Lastly, we used the Arrhenius equation and determined that the activation energy for the decomposition of RhB using AC was approximately 35.9 kJ mol−1, which was very low. Hopefully it will create a great platform for the degradation of other toxic dye in near future.


2019 ◽  
Vol 6 (9) ◽  
pp. 191019 ◽  
Author(s):  
Shang Wang ◽  
Zhaolian Han ◽  
Tingting Di ◽  
Rui Li ◽  
Siyuan Liu ◽  
...  

The pod-shaped TiO 2 nano burst tubes (TiO 2 NBTs) were prepared by the combination of electrospinning and impregnation calcination with oxalic acid (H 2 C 2 O 4 ), polystyrene (PS) and tetrabutyl titanate. The silver nanoparticles (AgNPs) were loaded onto the surface of TiO 2 NBTs by ultraviolet light reduction method to prepare pod-shaped Ag@TiO 2 NBTs. In this work, we analysed the effect of the amount of oxalic acid on the cracking degree of TiO 2 NBTs; the effect of the concentration of AgNO 3 solution on the particle size and loading of AgNPs on the surface of TiO 2 NBTs. Scanning electron microscopy and transmission electron microscopy investigated the surface morphology of samples. X-ray diffraction and X-ray photoelectron spectroscopy characterized the structure and composition of samples. Rhodamine B (RhB) solution was used to evaluate the photocatalytic activity of pod-shaped TiO 2 NBTs and Ag@TiO 2 NBTs. The results showed that TiO 2 NBTs degraded 91.0% of RhB under ultraviolet light, Ag@TiO 2 NBTs degraded 95.5% under visible light for 75 and 60 min, respectively. The degradation process of both samples was consistent with the Langmuir–Hinshelwood first-order kinetic equation. Therefore, the catalytic performance of the sample is: Ag@TiO 2 NBTs > TiO 2 NBTs > TiO 2 nanotubes.


2020 ◽  
Vol 10 (14) ◽  
pp. 4745
Author(s):  
Xiaoyu Du ◽  
Chihiro Kishima ◽  
Haixin Zhang ◽  
Naoto Miyamoto ◽  
Naoki Kano

In this study, chitosan beads modified with sodium dodecyl sulfate (SDS) were successfully synthesized and employed for the removal of chromium(VI) (Cr(VI)). The adsorption performance of the adsorbent (SDS-chitosan beads) was examined by batch experiments. The partition coefficient (PC) as well as the adsorption capacity were evaluated to assess the true performance of the adsorbent in this work. The adsorbent (SDS-chitosan beads) showed a maximum Cr(VI) adsorption capacity of 3.23 mg·g−1 and PC of 9.5 mg·g−1·mM−1 for Cr(VI). The prepared adsorbent was characterized by different techniques such as scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS) and Fourier transform-infrared spectroscopy (FT-IR). We used inductively coupled plasma mass spectrometry (ICP-MS) for the determination of Cr(VI) in solution. The experimental data could be well-fitted by pseudo-second-order kinetic and Langmuir isotherm models. The thermodynamic studies indicated that the adsorption process was favorable under the higher temperature condition. The SDS-modified chitosan beads synthesized in this work represent a promising adsorbent for removing Cr(VI).


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