scholarly journals Sustainable Chromium (VI) Removal from Contaminated Groundwater Using Nano-Magnetite-Modified Biochar via Rapid Microwave Synthesis

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 103
Author(s):  
Xiaoming Song ◽  
Yuewen Zhang ◽  
Nan Cao ◽  
Dong Sun ◽  
Zhipeng Zhang ◽  
...  
Keyword(s):  
Synthesis Method ◽  
Microwave Treatment ◽  
Contaminated Groundwater ◽  
Maximum Adsorption Capacity ◽  
Intraparticle Diffusion Model ◽  
Adsorption Mechanisms ◽  
Chromium Vi ◽  
Modified Biochar ◽  
Pseudo Second Order ◽  
Nano Fe3o4

This study developed a nano-magnetite-modified biochar material (m-biochar) using a simple and rapid in situ synthesis method via microwave treatment, and systematically investigated the removal capability and mechanism of chromium (VI) by this m-biochar from contaminated groundwater. The m-biochar was fabricated from reed residues and magnetically modified by nano-Fe3O4. The results from scanning electron microscopy (SEM) and X-ray diffraction (XRD) characterisations confirmed the successful doping of nano-Fe3O4 on the biochar with an improved porous structure. The synthesised m-biochar exhibited significantly higher maximum adsorption capacity of 9.92 mg/g compared with that (8.03 mg/g) of the pristine biochar. The adsorption kinetics followed the pseudo-second-order model and the intraparticle diffusion model, which indicated that the overall adsorption rate of Cr(VI) was governed by the processes of chemical adsorption, liquid film diffusion and intramolecular diffusion. The increasing of the pH from 3 to 11 significantly affected the Cr(VI) adsorption, where the capabilities decreased from 9.92 mg/g to 0.435 mg/g and 8.03 mg/g to 0.095 mg/g for the m-biochar and pristine biochar, respectively. Moreover, the adsorption mechanisms of Cr(VI) by m-biochar were evaluated and confirmed to include the pathways of electrostatic adsorption, reduction and complexation. This study highlighted an effective synthesis method to prepare a superior Cr(VI) adsorbent, which could contribute to the effective remediation of heavy metal contaminations in the groundwater.

Removal of acetaminophen (ACT) from aqueous solution by using nanosilica adsorbent: experimental study, kinetic and isotherm modeling

2020 ◽  
Vol 49 (1) ◽  
pp. 55-62
Author(s):  
Akbar Eslami ◽  
Zahra Goodarzvand Chegini ◽  
Maryam Khashij ◽  
Mohammad Mehralian ◽  
Marjan Hashemi
Keyword(s):  
Removal Rate ◽  
Synthesis Method ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
Content Type ◽  
Bet Analysis ◽  
Pseudo Second Order

Purpose A nanosilica adsorbent was prepared and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and BET. Design/methodology/approach The optimum conditions for the highest adsorption performance were determined by kinetic modeling. The adsorbent was used for the adsorption of acetaminophen (ACT), and the parameters affecting the adsorption were discussed like pH, initial concentration, contact time and adsorbent dosage. The adsorbent have been characterized by SEM, XRD and BET analysis. The kinetic models including pseudo-first-order and pseudo-second-order with Langmuir and Freundlich isotherm models were applied to investigate the kinetic and isotherms parameters. Findings The adsorption of ACT increased to around 95% with the increase of nanosilica concentration to 30 g/L. Moreover, the adsorption process of ACT follows the pseudo-second-order kinetics and the Langmuir isotherm with the maximum adsorption capacity of 609 mg/g. Practical implications This study provided a simple and effective way to prepare of nanoadsorbents. This way was conductive to protect environmental and subsequent application for removal of emerging pollutants from aqueous solutions. Originality/value The novelty of the study is synthesizing the morphological and structural properties of nanosilica-based adsorbent (specific surface area, pore volume and size, shape and capability) and improving its removal rate through optimizing the synthesis method; and studying the capability of synthesis of nanosilica-based adsorbent for removal of ACT as a main emerging pharmaceutical water contaminant.

scholarly journals Enhanced cadmium removal from water by hydroxyapatite subjected to different thermal treatments

2020 ◽  
Vol 69 (7) ◽  
pp. 678-693
Author(s):  
R. Aouay ◽  
S. Jebri ◽  
A. Rebelo ◽  
J. M. F. Ferreira ◽  
I. Khattech
Keyword(s):  
Electron Microscopy ◽  
Sorption Process ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Cadmium Removal ◽  
Sorption Behaviour ◽  
Adsorption Mechanisms ◽  
Transmission Electron ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Abstract Hydroxyapatite powders were synthesized according to a wet precipitation route and then subjected to heat treatments within the temperature range of 200–800 °C. The prepared samples were tested as sorbents for cadmium in an aqueous medium. The best performances were obtained with the material treated at 200 °C (HAp200), as the relevant sorbent textural features (SBET – specific surface area and Vp – total volume of pores) were least affected at this low calcination temperature. The maximum adsorption capacity at standard ambient temperature and pressure was 216.6 mg g−1, which increased to 240.7 mg g−1 by increasing the temperature from 25 to 40 °C, suggesting an endothermic nature of the adsorption process. Moreover, these data indicated that a thermal treatment at 200 °C enhanced the ability of the material in Cd2+ uptake by more than 100% compared to other similar studies. The adsorption kinetic process was better described by the pseudo-second-order kinetic model. Langmuir, Freundlich, and Dubinin–Kaganer–Radushkevich isotherms were applied to describe the sorption behaviour of Cd2+ ions onto the best adsorbent. Furthermore, a thermodynamic study was also performed to determine ΔH°, ΔS°, and ΔG° of the sorption process of this adsorbent. The adsorption mechanisms were investigated by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy-transmission electron microscopy (SEM-TEM) observations.

scholarly journals A Facilely Synthesized Tourmaline-Biochar Composite For Enhanced Removal of Cr (VI) From Aqueous Solution

2021 ◽  
Author(s):  
Qi Lu ◽  
Siyi Huang ◽  
Xiaorui Ma
Keyword(s):  
Aqueous Solution ◽  
Pyrolysis Temperature ◽  
Adsorption Property ◽  
Energy Dispersive Spectrometer ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
Adsorption Mechanisms ◽  
Monolayer Adsorption ◽  
Initial Ph ◽  
Pseudo Second Order

Abstract A tourmaline-biochar composite (TMBC) was facilely synthesized to effectively remove Cr (Ⅵ) from aqueous solution. The effects of different ratio (TM: BC) and pyrolysis temperature on TMBC adsorption performance were compared for optimal condition of TMBC preparation. The TMBC samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) and scanning electron microscope-energy dispersive spectrometer (SEM-EDS). The kinetics and thermodynamics were analyzed to investigate the sorption mechanism for removal of Cr (VI). The results showed that the proper pyrolysis temperature was 650℃, and the ratio of TM and BC was 1:3. SEM results showed that there are many pores in the biochar structure, which is helpful for tourmaline dispersion. The adsorption kinetics was fitted well by the pseudo-second-order model, indicating the sorption is related to chemical absorption. Freundlich adsorption isotherms suggested monolayer adsorption between Cr (Ⅵ) and TMBC, and the maximum adsorption capacity of TMBC for Cr (Ⅵ) was 53.10 mg/g at initial pH 4.0, which is more than twice higher than pristine TM (17.85 mg/g). Such adsorption mechanisms included water automatically polarized, ion exchange and electrode adsorption, among which the automatic polarization of water caused by tourmaline was the unique adsorption property of TMBC. So TMBC composite can be used as an economic adsorbent in the remediation of heavy metal pollution in water.

scholarly journals Fabrication of magnetic lignin-based adsorbent for removal of methyl orange dye from aqueous solution

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 5436-5449
Author(s):  
Chao Cao ◽  
Lupeng Shao ◽  
Lucian A. Lucia ◽  
Yu Liu
Keyword(s):  
Aqueous Solution ◽  
Methyl Orange ◽  
Influence Factors ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
Adsorption Mechanisms ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Methyl Orange Dye ◽  
Adsorption Desorption

Magnetic lignin-based adsorbent (MLA) was successfully fabricated to remove methyl orange dye from aqueous solution. The synthesized MLA was characterized by means of Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), N2 adsorption-desorption, scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM). In the process of adsorption, influence factors and recycling performance were considered, and the adsorption mechanisms such as isotherm and kinetics were investigated. The result showed that the equilibrium data was consisted with the Langmuir model with a maximum adsorption capacity of 85.0 mg/g. The adsorption kinetics followed a pseudo-second-order model. Based the adsorption performance, MLA showed good recyclability. Therefore, these results demonstrate that MLA could offer a great potential as an efficient and reusable adsorbent in the wastewater treatments.

scholarly journals Adsorption Behaviour of Chromium(VI) onto Surface Modified Sugarcane Waste

2013 ◽  
Vol 28 (1-2) ◽  
pp. 113-122
Author(s):  
Kedar Nath Ghimire ◽  
Deepak Wagle ◽  
Suman Lal Shrestha
Keyword(s):  
Volume Ratio ◽  
Freundlich Isotherm ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Adsorption Method ◽  
Chromium Vi ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Surface Modified

An effective chemically modified adsorbent based on sugarcane waste has been prepared by treating with concentrated sulphuric acid in 2:1weight/volume ratio. Thus prepared adsorbent has been found to be effective in the adsorption of chromium from aqueous medium. The efficacy of the adsorbent in the removal of chromium was evaluated by batch adsorption method. The effect of initial concentration, contact time and pH of the solution was investigated. The maximum adsorption capacity onto this adsorbent was found to be 195 mg/g at their optimal pH 1 at which unmodified bagasse has only 58 mg/g. The characterization of adsorbent was done by determining surface area and Boehm’s titration method. Freundlich isotherm and pseudo-second order kinetic model gave better explanation of the adsorption process.

Highly efficient removal of chromium(VI) from aqueous solution using polyaniline/sepiolite nanofibers

2014 ◽  
Vol 70 (7) ◽  
pp. 1236-1243 ◽  
Author(s):  
Jun Chen ◽  
Xiaoqin Hong ◽  
Qingdong Xie ◽  
Diankai Li ◽  
Qianfeng Zhang
Keyword(s):  
Weight Ratio ◽  
Chemical Oxidation ◽  
Maximum Adsorption Capacity ◽  
In Situ Chemical Oxidation ◽  
Highly Efficient ◽  
Chromium Vi ◽  
Chemical Oxidation Polymerization ◽  
Pseudo Second Order ◽  
Sepiolite Nanofibers

Polyaniline/sepiolite (PANI/sepiolite) nanofibers were prepared by in situ chemical oxidation polymerization in the presence of sepiolite. The effect of aniline/sepiolite weight ratio on the nanostructure of PANI/sepiolite composites was investigated by field-emission scanning electron microscopy. The adsorption of Cr(VI) onto the PANI/sepiolite nanofibers was highly dependent on pH values. The pseudo-second-order and Langmuir isothermal models can well describe the adsorption kinetics and adsorption isotherm, respectively. The maximum adsorption capacity of the PANI/sepiolite nanofibers for Cr(VI) was up to 206.6 mg/g at 25 °C and increased with the increase in temperature. Desorption experiments indicated that PANI/sepiolite can be regenerated and reused for two consecutive cycles with no loss of its removal efficiency. PANI/sepiolite nanofibers can be used as a highly efficient and economically viable adsorbent for Cr(VI) removal due to their excellent adsorption characteristics.

Chromium (VI) adsorption onto activated sulfate lignin

2009 ◽  
Vol 4 (2) ◽  
Author(s):  
Nassima Tazrouti ◽  
Moussa Amrani
Keyword(s):  
Adsorption Capacity ◽  
Contact Time ◽  
Analytical Data ◽  
Order Equation ◽  
Second Order ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Adsorption Model ◽  
Chromium Vi ◽  
Pseudo Second Order

Activated lignin having surface area of 1023 m2.g-1 has been prepared from sulfate lignin that was treated by 30 % H2O2 and carbonized at 300 °C in order to test the chromium (VI) adsorption from aqueous solution. The influence of contact time, pH, initial concentration of adsorbent and adsorbate and temperature on the adsorption capacity were investigated. The maximum removal of Cr(VI) was found to be 92,36 % at pH=2 and contact time of 80 min. Optimal concentration of lignin and Cr(VI) were found to be 3.8 g.l-1 and 180 mg.l-1, respectively. The adsorption kinetics was tested pseudo-first-order and pseudo-second-order equation. The analytical data were fitted well in a pseudo-second-order equation and the rate of removal of chromium was found to speed up with increasing temperature. Activation energy for the adsorption process was found to be 18.19 Kj.mol-1. The Langmuir and Freundlich adsorption isotherm models were applied to describe the isotherm and isotherm constants for the adsorption of Cr (VI) on lignin. These constants and correlation coefficients of the isotherm models were calculated and compared. Results indicated that Cr (VI) uptake could be described by the Langmuir adsorption model. The maximum adsorption capacity (qm) of Cr (VI) on lignin was 75.75 mg.g-1 at temperature of 40°C. The dimensionless equilibrium parameter (RL) signified a favorable adsorption of Cr (VI) on lignin and was found between 0.0601 and 0.818 (0<RL<1). The thermodynamic parameters like ΔG°, ΔS° and ΔH° were calculated and it has been found that the reaction was spontaneous and endothermic in nature. This study indicates that lignin has the potential to become an effective and economical adsorbent for removal Cr (VI) from the waste water.

scholarly journals Adsorption of Chromium (VI) by Cu (I)-MOF in Water: Optimization, Kinetics, and Thermodynamics

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Hongxue Qi ◽  
Xianjun Niu ◽  
Haipeng Wu ◽  
Xiuping Liu ◽  
Yongqiang Chen
Keyword(s):  
Adsorption Capacity ◽  
Low Cost ◽  
Entropy Change ◽  
Maximum Adsorption Capacity ◽  
Sem Images ◽  
First Order ◽  
Chromium Vi ◽  
Function Change ◽  
Pseudo Second Order ◽  
Pseudo First Order

To investigate the adsorption behavior of Cu (I)-MOF material for chromium (VI) in water, the parameters of influencing adsorption were optimized and found as follows: the optimal pH was 6 for the adsorption of Cr (VI) by the Cu (I)-MOF, the optimal amount of adsorbent was 0.45 g·L−1, and the adsorption saturation time was within 180 min. Subsequently, the kinetics results were fitted by four models such as pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. Among them, the adsorption of chromium (VI) was more inclined to the pseudo-first-order model (Radj2 = 0.9230). Then, the isotherm data were fitted by Langmuir and Freundlich models. The results indicated that Langmuir isotherm was the excellent match model (Radj2 = 0.9827). It belongs to a monolayer adsorption, and the maximum adsorption capacity was 95.92 mg·g−1. Subsequently, the thermodynamic parameters of the adsorption were calculated as follows: enthalpy change (ΔHθ) was −8.583 kJ·mol−1, entropy change (ΔSθ) was −8.243 J·mol−1 K−1, and the Gibbs function change (ΔGθ) was less than zero in the temperature range of 288–328 K, indicating that the reaction was spontaneous. Finally, both the spectra of infrared and XPS supported the adsorption mechanism that belonged the ion exchange. The spectra of XRD and SEM images shown that the structure of Cu (I)-MOF remained stable for at least 3 cycles. In conclusion, Cu (I)-MOF material has a high adsorption capacity, good water stability, low cost, and easy to prepare in large quantities in practical application. It will be a promising adsorbent for the removal of Cr (VI) from water.

scholarly journals Modified biochar from Moringa seed powder for the removal of diclofenac from aqueous solution

2019 ◽  
Vol 27 (7) ◽  
pp. 7318-7327 ◽  
Author(s):  
Afrouz Bagheri ◽  
Emmanuel Abu-Danso ◽  
Jibran Iqbal ◽  
Amit Bhatnagar
Keyword(s):  
Aqueous Solution ◽  
Sem Analysis ◽  
Parent Material ◽  
Point Of Zero Charge ◽  
Maximum Adsorption Capacity ◽  
Ftir Analysis ◽  
Modified Biochar ◽  
Pseudo Second Order ◽  
Ph Conditions ◽  
Synthesized Materials

AbstractIn this study, Moringa seed powder (MSP) was pyrolyzed at 450 °C to synthesize Moringa seed powder biochar (MSPB) and treated with phosphoric acid (H3PO4) to synthesize phosphate-modified Moringa seed powder biochar (MSPB-HPO) as an adsorbent for the removal of diclofenac (Dfc) from aqueous solution. Fourier transform infrared (FTIR) analysis, energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and pH point of zero charge (pHpzc) were conducted to give more insight into the adsorbent’s properties. The SEM analysis showed the transformations in the surface morphology from the parent material to the synthesized materials after the thermal and acid treatment. EDS analysis revealed the variation in the elemental composition of the materials prior to and after adsorption of Dfc ions. The FTIR analysis showed changes and peak intensities of functional groups involved in Dfc removal. The pHpzc showed the charge carried by MSPB-HPO in different pH conditions. Isotherm data best matched the Sips model, and the pseudo-second-order model best described the adsorption kinetics. The maximum adsorption capacity of MSPB-HPO by Sips model was found to be 100.876 mg g−1.

scholarly journals Adsorptive Removal of Antibiotic Ciprofloxacin from Aqueous Solution Using Protein-Modified Nanosilica

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 57 ◽  
Author(s):  
Tien Duc Pham ◽  
Thi Ngan Vu ◽  
Hai Long Nguyen ◽  
Pham Hai Phong Le ◽  
Thi Sim Hoang
Keyword(s):  
Ionic Strength ◽  
Adsorption Isotherms ◽  
High Performance ◽  
Maximum Adsorption Capacity ◽  
Adsorption Mechanisms ◽  
Adsorptive Removal ◽  
Step Model ◽  
Anionic Species ◽  
Pseudo Second Order ◽  
Ft Ir

The present study aims to investigate adsorptive removal of molecular ciprofloxacin using protein-modified nanosilica (ProMNS). Protein was successfully extracted from Moringa seeds while nanosilica was synthesized from rice husk. Fourier-transform infrared (FTIR), ultraviolet visible (UV-Vis) and high-performance liquid chromatography (HPLC) were used to evaluate the characterization of protein. Adsorption of protein onto nanosilica at different pH and ionic strength was thoroughly studied to modify nanosilica surface. The removal efficiency of antibiotic ciprofloxacin (CFX) increased from 56.84% to 89.86% after surface modification with protein. Effective conditions for CFX removal using ProMNS were systematically optimized and found to be pH 7.0, adsorption time 90 min, adsorbent dosage 10 mg/mL, and ionic strength 1 mM KCl. A two-step model was successfully used to fit the adsorption isotherms of CFX onto ProMNS at different ionic strength while a pseudo-second-order model could fit adsorption kinetic of CFX onto ProMNS very well. Maximum adsorption capacity was very high that reached to 85 mg/g. Adsorption of CFX onto ProMNS decreased with increasing KCl concentration, suggesting that adsorption of CFX onto ProMNS is mainly controlled by electrostatic attraction between positively charged ProMNS surface and anionic species of CFX. Adsorption mechanisms of CFX onto ProMNS were discussed in detail based on adsorption isotherms, the change in surface charge by zeta potentail and the change in functional groups by FT-IR. The removal of CFX after three regenerations was greater than 73% while CFX removal from an actual hospital wastewater using ProMNS reached to 70%. Our results suggest that ProMNS is a new and eco-friendly adsorbent to remove antibiotics from aqueous solutions.

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