scholarly journals Adsorption of Hexavalent Chromium Using Banana Pseudostem Biochar and Its Mechanism

2018 ◽  
Vol 10 (11) ◽  
pp. 4250 ◽  
Author(s):  
Shuang Xu ◽  
Weiguang Yu ◽  
Sen Liu ◽  
Congying Xu ◽  
Jihui Li ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Pyrolysis Temperature ◽  
Low Cost ◽  
Surface Adsorption ◽  
Maximum Adsorption Capacity ◽  
X Ray ◽  
Adsorption Processes ◽  
Different Temperatures ◽  
Pseudo Second Order ◽  
Porosity Analysis

A low-cost biochar was prepared through slow pyrolysis of banana pseudostem biowaste at different temperatures, and characterized by surface area and porosity analysis, scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). It was shown that the biochar prepared at low pyrolysis temperature was rich in oxygen-containing groups on the surface. Adsorption experiments revealed that the biochar prepared at 300 °C (BB300) was the best adsorbent for Cr(VI) with 125.44 mg/g maximum adsorption capacity at pH 2 and 25 °C. All the adsorption processes were well described by pseudo-second-order and Langmuir models, indicating a monolayer chemiadsorption. Furthermore, it was demonstrated that adsorption of Cr(VI) was mainly attributed to reduction of Cr(VI) to Cr(III) followed by ion exchange and complexation with the biochar.

scholarly journals Removal of Cesium and Strontium From Radioactive Wastewater by Prussian Blue Nanorods

2022 ◽  
Author(s):  
Chuqing Yao ◽  
Yaodong Dai ◽  
Shuquan Chang ◽  
Haiqian Zhang
Keyword(s):  
Prussian Blue ◽  
Photoelectron Spectroscopy ◽  
Adsorption Process ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Radioactive Wastewater ◽  
Pseudo Second Order ◽  
Co Precipitation ◽  
Solvothermal Methods

Abstract In this work, novel Prussian blue tetragonal nanorods were prepared by template-free solvothermal methods for removal of radionuclide Cs and Sr. It was worth that Prussian blue nanorods exhibited the better adsorption performance than co-precipitation PB or Prussian blue analogue composites. Thermodynamic analysis implied that adsorption process was spontaneous and endothermic which was described well with Langmuir isotherm and pseudo-second-order equation, the maximum adsorption capacity of PB nanorod was estimated to be 194.26 mg g-1 and 256.62 mg g-1 for Cs+ and Sr2+. The adsorption mechanism of Cs+ and Sr2+ was studied by X-ray photoelectron spectroscopy, X-ray diffraction and 57Fe Mössbaure spectroscopy, the results revealed that Cs+ entered in PB crystal to generate a new phase, the most of Sr2+ was trapped in internal crystal and the other exchanged Fe2+. Furthermore, the effect of co-existing ions and pH for PB adsorption process were also investigated. The results suggest that PB nanorods were outstanding candidate for removal of Cs+ and Sr2+ from radioactive wastewater.

Synthesis of magnetic biochar derived from cotton stalks for the removal of Cr(VI) from aqueous solution

2019 ◽  
Vol 79 (11) ◽  
pp. 2106-2115 ◽  
Author(s):  
Fengfeng Ma ◽  
Baowei Zhao ◽  
Jingru Diao
Keyword(s):  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Cotton Stalk ◽  
Magnetic Biochar ◽  
X Ray ◽  
Cotton Stalks ◽  
Pseudo Second Order ◽  
Co Precipitation

Abstract A magnetic cotton stalk biochar (MCSBC) was synthesized through chemical co-precipitation, based on cotton stalk biochar (CSBC). The MCSBC and CSBC were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and vibrating sample magnetometry. The characterization analyses showed that the magnetization process endowed the CSBC with excellent magnetic properties with a superparamagnetic magnetization of 27.59 emu/g. Batch adsorption experiment results indicated that the Cr(VI) maximum adsorption capacity of MCSBC was 20.05 mg/g, which was higher than that of CSBC (18.77 mg/g). The adsorption kinetic data were well fitted by the pseudo-second-order model and the adsorption isotherms were well represented by the Sips isotherm model. The thermodynamic studies indicated that the adsorption process was spontaneous and endothermic, and the entropy increased. The potential adsorption mechanism was the electrostatic adsorption of anionic Cr(VI) to the positively charged MCSBC surface, the reduction of Cr(VI) into Cr(III) and the complexation of Cr(III) by oxygen-containing functional groups of MCSBC. The regeneration studies showed that MCSBC kept 80% of its initial Cr(VI) adsorption capacity in the cycle. All the findings suggest that this novel magnetic biochar could be used in the field of Cr(VI)-containing wastewater treatment.

scholarly journals The adsorption behavior and mechanism investigation of Cr(VI) ions removal by poly(2-(dimethylamino)ethyl methacrylate)/poly(ethyleneimine) gels

2015 ◽  
Vol 80 (7) ◽  
pp. 889-902 ◽  
Author(s):  
Zhengbo Hou ◽  
Weixia Zhu ◽  
Hang Song ◽  
Pengfei Chen ◽  
Shun Yao
Keyword(s):  
Photoelectron Spectroscopy ◽  
Adsorption Process ◽  
Interaction Mechanism ◽  
Langmuir Model ◽  
Adsorption Behavior ◽  
Maximum Adsorption Capacity ◽  
X Ray ◽  
Ethyl Methacrylate ◽  
Pseudo Second Order ◽  
Scanning Electron

The composite hydrogels based on N,N?-dimethylamino ethyl methacrylate (DMAEMA) and polyethyleneimine (PEI) were prepared by amino radical polymerization and confirmed by Fourier Transform Infrared Spectra (FTIR) and elemental analysis. Then adsorption behavior and mechanism of Cr(VI) ions on the obtained materials were investigated with scanning electron microscope, Zeta potential and thermal gravity analysis, etc. The adsorption process was found to follow the pseudo-second order kinetics and Langmuir model, and the maximum adsorption capacity of Cr(VI) ions reached 122.8 mg g-1. X-ray photoelectron spectroscopy (XPS) and pH analysis revealed that the Cr(VI) ions were adsorbed into the gels through electrostatic interaction mechanism, and SO42- in the solution had a great effect on the adsorption process. In addition, high pH and ionic strength could reduce the uptakes of adsorbate, which could be used for desorption of Cr(VI) ions from the gels.

scholarly journals Synthesis, Characterization, and Adsorptive Properties of Fe3O4/GO Nanocomposites for Antimony Removal

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Xiuzhen Yang ◽  
Tengzhi Zhou ◽  
Bozhi Ren ◽  
Zhou Shi ◽  
Andrew Hursthouse
Keyword(s):  
Photoelectron Spectroscopy ◽  
Adsorption Process ◽  
Maximum Adsorption Capacity ◽  
X Ray ◽  
Number Of Factors ◽  
Infrared Spectrometer ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Solid Liquid ◽  
Solid Liquid Separation

A magnetic Fe3O4/GO composite with potential for rapid solid-liquid separation through a magnetic field was synthesized using GO (graphene oxide) and Fe3O4 (ferriferous oxide). Characterization of Fe3O4/GO used scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FT-IR), and Vibrating Sample Magnetometer (VSM). A number of factors such as pH and coexisting ions on adsorbent dose were tested in a series of batch experiments. The results showed that GO and Fe3O4 are strongly integrated. For pH values in the range of 3.0~9.0, the removal efficiency of Sb(III) using the synthesized Fe3O4/GO remained high (95%). The adsorption showed good fit to a pseudo-second-order and Langmiur model, with the maximum adsorption capacity of 9.59 mg/g maintained across pH 3.0–9.0. Thermodynamic parameters revealed that the adsorption process was spontaneous and endothermic. Analysis by X-ray photoelectron spectroscopy (XPS) showed that the adsorption process is accompanied by a redox reaction.

scholarly journals Equilibrium and kinetics studies of Direct blue 71 adsorption from aqueous solutions using modified zeolite

2017 ◽  
Vol 36 (1-2) ◽  
pp. 80-94 ◽  
Author(s):  
Nezam Mirzaei ◽  
Amir Hossein Mahvi ◽  
Hooshyar Hossini
Keyword(s):  
Low Cost ◽  
Second Order ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
Modified Zeolite ◽  
X Ray ◽  
Direct Blue ◽  
Equilibrium And Kinetics ◽  
Pseudo Second Order ◽  
Direct Blue 71

This study deals with the application of Iranian zeolite as a low cost adsorbent for the removal of the Direct blue 71 (DB 71) from colored solution. Important parameters including equilibrium and contact time, initial dye concentration, effect of pH, and zeolite dosage were evaluated. Maximum dye removal was obtained at about 99.8% for 25 mg/L at 120 min of equilibrium. Higher adsorption efficiency of direct dye was obtained at higher dose and acidic pH. To analyze the adsorption equilibrium and kinetic, Langmuir, Freundlich, and Temkin isotherms as well as four kinetic models encompassing pseudo first-order, pseudo second-order, intraparticle diffusion, and Elovich were evaluated. The Langmuir isotherm ( R2 = 0.995) and pseudo second-order models, gave the best fit to equilibrium experimental data. In Langmuir analysis, the maximum adsorption capacity (qm) by 13.66 mg/g was determined. Finally, the characteristics of zeolite including both natural and modified, such as compositions, surface morphology by X-ray diffraction technique (XRD), X-ray fluorescence (XRF), and scanning electron microscopy (SEM) were obtained. According to XRF analysis, it was demonstrated that Al2O3 and SiO2 are the most part of natural and modified zeolite. Furthermore, the clinoptilolite was determined as the significant crystalloid phase by XRD pattern.

scholarly journals Selective adsorption of PHC and regeneration of washing effluents by modified diatomite

2020 ◽  
Vol 81 (10) ◽  
pp. 2066-2077
Author(s):  
Zhuoqi Xu ◽  
Gengbo Ren ◽  
Yanying Zhu ◽  
Xiaodong Ma ◽  
Hongrui Li ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Selective Adsorption ◽  
Low Cost ◽  
Soil Washing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Monolayer Adsorption ◽  
Pseudo Second Order ◽  
Adsorption Desorption ◽  
Modified Diatomite

Abstract Selective removal of petroleum hydrocarbons (PHCs) from soil washing effluents is the key to the surfactant-enhanced soil washing technology. In this study, the diatomite was modified by nonionic surfactant TX-100 and applied in the selective adsorption of PHCs in the soil washing effluents. The modified diatomites were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, N2 adsorption/desorption and X-ray photoelectron spectroscopy respectively. The adsorption process followed the pseudo-second-order model and the adsorption isotherms indicated that the interaction between PHCs and modified diatomite was monolayer adsorption. The important operating factors such as TX-100 dosage, adsorbent dosage, time and temperature were optimized. With the participation of the low-cost adsorbent TX3-Db with high adsorption capacity, the recovery efficiency of the washing effluents was still up to 78.9% after three cycles. A selective adsorption mechanism, based on steric hindrance and electrostatic repulsion, was proposed to explain the removal of PHCs from washing effluents.

scholarly journals Application of a Low-Cost Cellulose-Based Bioadsorbent for the Effective Recovery of Terbium Ions from Aqueous Solutions

2020 ◽  
Author(s):  
Lorena Alcaraz ◽  
Dayana Nathaly Saquinga ◽  
Floralba López ◽  
Lola de Lima ◽  
Francisco J. Alguacil ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Crystallinity Index ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
X Ray ◽  
Cellulose Structure ◽  
13C Nuclear Magnetic Resonance ◽  
Before And After ◽  
Pseudo Second Order

Preparation of a low-cost cellulose-based bioadsorbent from the cellulosic material extracted from the rose stems (CRS) was carried out; rose stems were considered agricultural wastes. After the required pretreatment of this waste, and its further treatment with an acidic mixture of acetic and nitric acids, the CRS product was yielded. The resulting bioadsorbent was characterized by several techniques, such as X-ray diffraction, which revealed diffraction maxima related to cellulose structure, whose calculated crystallinity index (CrI) was 75 %. In addition, Fourier Transform Infrared spectroscopy (FTIR), 13C Nuclear Magnetic Resonance (NMR), and X-ray Photoelectron Spectroscopy (XPS) showed signs of acetylation of the sample, also, the thermal properties of the solid was evaluated through Thermogravimetric Analysis (TGA). Scanning Electron Microscopy (SEM) showed cellulose fibers before and after the adsorption process, some particles with not regular shapes were also observed. The CRS bioadsorbent was used in the effective adsorption of valuable Tb(III) from aqueous solution. The adsorption data resulted in a better fit to the Freundlich isotherm, and pseudo-second-order kinetic models; however, chemisorption had not been ruled out. Finally, desorption experiments revealed a recovery of terbium ions with an efficiency of 97 % from terbium-loaded bioadsorbent.

Diatomite modified by TiO2 for adsorption of U(VI)

2018 ◽  
Vol 106 (9) ◽  
pp. 733-742 ◽  
Author(s):  
Ni Yuan ◽  
Peng Liu ◽  
Wangsuo Wu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Water Environment ◽  
X Ray ◽  
Ph Values ◽  
Batch Technique ◽  
Adsorption Processes ◽  
Novel Material ◽  
Pseudo Second Order ◽  
Synthesized Materials

Abstract Diatomite was modified with TiO2. The synthesized materials were characterized and used for removal of U(VI) from aqueous solutions. The influences of pH, contact time and temperature on U(VI) adsorption onto TiO2@diatomite were studied by batch technique, and X-ray photoelectron spectroscopy (XPS) was employed to analyze the experimental data. We compared the adsorption of U(VI) onto natural diatomite, TiO2 and TiO2@diatomite made by sol-gel method. The dynamic process showed that the adsorption of U(VI) onto TiO2@diatomite matched the pseudo-second-order kinetics model, and the adsorption of U(VI) was significantly dependent on pH values. Through simulating the adsorption isotherms by Langmuir, Freundlich and Dubini–Radushkevich (D–R) models, respectively, it could be seen that the adsorption patterns of U(VI) onto TiO2@diatomite were mainly controlled by surface complexation, and the adsorption processes were endothermic and spontaneous. The modification of diatomite by TiO2 shows a novel material for removing U(VI) from water environment for industrialized application.

scholarly journals Evaluation for Simultaneous Removal of Anionic and Cationic Dyes onto Maple Leaf-Derived Biochar Using Response Surface Methodology

2020 ◽  
Vol 10 (9) ◽  
pp. 2982 ◽  
Author(s):  
Yong-Keun Choi ◽  
Ranjit Gurav ◽  
Hyung Joo Kim ◽  
Yung-Hun Yang ◽  
Shashi Kant Bhatia
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Photoelectron Spectroscopy ◽  
Pyrolysis Temperature ◽  
Rapid Development ◽  
Maximum Adsorption Capacity ◽  
Aqueous Mixtures ◽  
X Ray ◽  
Anionic Dye ◽  
Adsorption Temperature

Rapid development in the printing and dying industry produces large amounts of wastewater, and its discharge in the environment causes pollution. Keeping in view the carcinogenic and mutagenic properties of various dyes, it is important to treat dyed wastewater. Maple leaf biochars were produced at different pyrolysis temperatures, i.e., 350 °C, 550 °C, and 750 °C, characterized for physicochemical properties and used for the removal of cationic (methylene blue (MB)) and anionic dye (congo red (CR)). Response surface methodology (RSM) using three variables, i.e., pH (4, 7, and 10), pyrolysis temperature (350 °C, 550 °C, and 750 °C), and adsorption temperature (20 °C, 30 °C, and 40 °C), was designed to find the optimum condition for dyes removal. X-ray diffraction (XRD) analysis showed an increase in CaCO3 crystallinity and a decrease in MgCO3 crystallinity with the increase of pyrolysis temperature. RSM design results showed that maple biochar showed maximum adsorption capacity for cationic dye at higher pH (9–10) and for anionic dye at pH 4-6, respectively. Under the selected condition of pH 7 and an adsorption temperature of 30 °C, biochar MB550 was able to remove MB and CR by 68% and 74%, respectively, from dye mixtures. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses showed that MB550 was able to remove both dyes simultaneously from the aqueous mixtures.

scholarly journals Green Synthesis of A Novel MXene–CS Composite Applied in Treatment of Cr(VI) Contaminated Aqueous Solution

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 524
Author(s):  
Hongyou Wan ◽  
Lan Nan ◽  
Huikai Geng ◽  
Wei Zhang ◽  
Huanhuan Shi
Keyword(s):  
Photoelectron Spectroscopy ◽  
Environmental Concern ◽  
Maximum Adsorption Capacity ◽  
Aqueous Environment ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
X Ray ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Xrd Patterns

The considerable amount of Cr(VI) pollutants in the aqueous environment is a significant environmental concern that cannot be ignored. A series of novel Mxene–CS inorganic–organic composite nanomaterials synthesized by using the solution reaction method was applied to treat the Cr(VI) contaminated water. The Mxene–CS composites were characterized through SEM (scanning electron microscope), XRD (X–ray diffraction), XPS (X–ray photoelectron spectroscopy), and FTIR (Fourier transform infrared). The XRD patterns (observed at 2θ of 18.1°, 35.8°, 41.5°, and 60.1°) and the FT–IR spectra (-NH2 group for 1635 and 1517 cm−1, and -OH group for 3482 cm−1) illustrated that CS was successfully loaded on the Mxene. The effects of solution pH, the dosage of Mxene–CS, and duration time on the adsorption of Cr(VI) by synthesized Mxene–CS were investigated. The removal efficiency of Cr(VI) was increased from 12.9% to 40.5% with Mxene–CS dosage ranging from 0.02 to 0.12 g/L. The adsorption process could be well fitted by the pseudo–second–order kinetics model, indicating chemisorption occurred. The Langmuir isotherm model could be better to describe the process with a maximum adsorption capacity of 43.1 mg/g. The prepared novel Mxene–CS composite was considered as an alternative for adsorption of heavy metals from wastewater.

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