scholarly journals Adsorption of Lead (II) from Aqueous Solution with High Efficiency by Hydrothermal Biochar Derived from Honey

Author(s):  
Bo Wang ◽  
Jie Yu ◽  
Hui Liao ◽  
Wenkun Zhu ◽  
Pingping Ding ◽  
...  

A novel natural honey hydrothermal biochar (HHTB) was prepared using natural honey as raw material. The as-prepared adsorbent was applied to adsorb Pb2+ from aqueous solution and characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy to investigate the structure and morphology change of the adsorbent before and after Pb2+ adsorption. The influence of the pH, initial Pb2+ concentration, temperature, and contact time on the adsorption of Pb2+ was systematically investigated. The results revealed that the adsorption capacity for Pb2+ is up to 133.2 mg·g−1 at initial pH of 5.0 and adsorption temperature of 298 K. Meanwhile, the adsorption of Pb2+ on HHTB can be well fitted by the pseudo-second-order model and Langmuir isotherm model. The adsorbent had great selectivity for Pb2+ from the aqueous solution containing coexisting ions including Cd2+, Co2+, Cr3+, Cu2+, Ni2+ and Zn2+. Furthermore, the adsorption of Pb2+ on HHTB was attributed to complexation coordination, where it involved hydroxyl and carboxylic groups on HHTB in the process of adsorption of Pb2+.

Author(s):  
Haixia Wang ◽  
Mingliang Zhang ◽  
Hongyi Li

Maize straw biochar-supported nanoscale zero-valent iron composite (MSB-nZVI) was prepared for efficient chromium (Cr) removal through alleviating the aggregation of zero-valent iron particles. The removal mechanism of MSB-nZVI was investigated by scanning electron microscopy with energy dispersive X-ray (SEM-EDX), X-ray diffractometry (XRD), and X-ray photoelectron spectroscopy (XPS). Cr(VI) removal from aqueous solution by MSB-nZVI was greatly affected by pH and initial concentration. The removal efficiency of Cr(VI) decreased with increasing pH, and the removal kinetics followed the pseudo-second-order model. XRD patterns of MSB-nZVI before and after reaction showed that reduction and precipitation/co-precipitation (FeCr2O4, Fe3O4, Fe2O3) occurred with the conversion of Cr(VI) to Cr(III) and Fe(0) to Fe(II)/Fe(III). The produced precipitation/co-precipitation could be deposited on the MSB surface rather than being only coated on the surface of nZVI particles, which can alleviate passivation of nZVI. For remediation of Cr(VI)-contaminated saline–alkali soil (pH 8.6–9.0, Cr 341 mg/kg), the released amount of Cr(VI) was 70.7 mg/kg, while it sharply decreased to 0.6–1.7 mg/kg at pH 4.0–8.0, indicating that the saline–alkali environment inhibited the remediation efficiency. These results show that MSB-nZVI can be used as an effective material for Cr(VI) removal from aqueous solution and contaminated soil.


2020 ◽  
Vol 81 (6) ◽  
pp. 1114-1129 ◽  
Author(s):  
Jun Wang ◽  
Qinglong Xie ◽  
Ao Li ◽  
Xuejun Liu ◽  
Fengwen Yu ◽  
...  

Abstract In this study, an efficient route to synthesizing polyethyleneimine-modified ultrasonic-assisted acid hydrochar (PEI-USAH) is developed and reported. Ultrasonic irradiation technique was used as surface modification method to shorten the crosslinking reaction for hydrochar and polyethyleneimine (PEI). The PEI-USAH showed an excellent adsorption capacity for Cr(VI) from aqueous solution. The physicochemical properties of this PEI-modified adsorbent were comparatively characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller analysis and CNHS analysis. The effects of contact time, initial pH, and biosorbent dose on adsorption capacities were investigated. The batch adsorption experiments showed that PEI-USAH possessed the maximum adsorption capacities of 94.38 mg/g and 330.84 mg/g for initial Cr(VI) concentration of 100 mg/L and 500 mg/L, respectively. Furthermore, this adsorption process could be fitted to Langmuir adsorption and described by the pseudo second order kinetic model. Based on the above findings, PEI-USAH could be used as a potential adsorbent for removal of Cr(VI) from wastewater.


2016 ◽  
Vol 75 (5) ◽  
pp. 1051-1058 ◽  
Author(s):  
Qiujin Jia ◽  
Wanting Zhang ◽  
Dongping Li ◽  
Yulong Liu ◽  
Yuju Che ◽  
...  

Hydrazinolyzed cellulose-graft-polymethyl acrylate (Cell-g-PMA-HZ), an efficient adsorbent for removal of Cd(II) and Pb(II) from aqueous solution, has been prepared by ceric salt-initiated graft polymerization of methyl acrylate from microcrystalline cellulose surface and subsequent hydrazinolysis. The influences of initial pH, contact time, and temperature on adsorption capacity of Cell-g-PMA-HZ as well as adsorption equilibrium, kinetic and thermodynamic properties were examined in detail. As for Cd(II) adsorption, kinetic adsorption can be explained by pseudo-second-order, while adsorption isotherm fits well with Langmuir isotherm model, from which maximum equilibrium adsorption capacity can be derived as 235.85 mg g−1 at 28 °C. Further thermodynamic investigation indicated that adsorption of Cd(II) by adsorbent Cell-g-PMA-HZ is endothermic and spontaneous under studied conditions. On the other hand, isotherm of Pb(II) adsorption fits well with Freundlich isotherm model and is more likely to be a physical-adsorption-dominated process. Consecutive adsorption–desorption experiments showed that Cell-g-PMA-HZ is reusable with satisfactory adsorption capacity.


Author(s):  
Chunlian Hu ◽  
Wei Zhang ◽  
Yuantao Chen ◽  
Na Ye ◽  
DaWa YangJi ◽  
...  

Abstract Herein adsorption studies were proposed on a carboxylated sludge biochar (CSB) material modified by HNO3 to assess its capacity in the removal of cobalt from aqueous solution. The as-prepared sludge biochar material were characterized by Brunaure-Emmett-Teller (BET), Fourier transform infrared (FT-IR), Thermogravimetric analysis (TGA), Energy-dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The isotherm process could be well described by Langmuir isotherm model. The adsorption kinetics indicated that cobalt adsorption followed pseudo-second-order kinetic model. The mechanism between Co(II) and biochar involved electrostatic interaction, ion exchange, surface complexation and physical function. The adsorption capacity on CSB was as high as 72.27 mg·g−1, surpassing original sludge biochar (SB). This is due to the fact that CSB had abundant oxygen-containing functional groups and many hydroxyls, as well as, the BET surface areas increased when SB was modified by HNO3, which stimulate adsorption effect. Therefore, this work shows that CSB could be used as an efficient adsorbent to remove Co(II) in the wastewater.


2013 ◽  
Vol 68 (11) ◽  
pp. 2441-2447 ◽  
Author(s):  
Heng Lin ◽  
Liwei Hou ◽  
Hui Zhang

The removal of Orange II in aqueous solution by Fe3O4 enhanced anode oxidation (EC/Fe3O4 process) was performed in an electrochemical reactor. The process involved the use of a dimensionally stable anode and a stainless steel cathode. Fe3O4 was performed as particle electrodes to increase mass transfer coefficient and reduce energy consumption. Various parameters were investigated to optimize the process, including initial pH, Fe3O4 dosage and current density. The results indicated that the decolorization of Orange II followed pseudo first-order kinetics. The decolorization was favorable in acidic media than in neutral or alkaline solution, while it increased with the Fe3O4 dosage and current density. The total organic carbon (TOC) removal efficiency was 33.2% after 120 min reaction. The X-ray photoelectron spectroscopy was applied to investigate the surface properties of Fe3O4 before and after reaction.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Ch. Suresh ◽  
D. Harikisore Kumar Reddy ◽  
Yapati Harinath ◽  
B. Ramesh Naik ◽  
K. Seshaiah ◽  
...  

A biosorbent was prepared by using wood apple shell (WAS) powder and studied its application for the removal of Cd(II) from aqueous solution by a batch method. The biosorbent was characterized by infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and elemental analysis. WAS is principally made up of lignin and cellulose, containing functional groups such as alcoholic, ketonic, and carboxylic groups which can be involved in complexation reactions with Cd(II). The effect of experimental parameters like initial pH, contact time, metal ion concentration, and sorbent dose on adsorption was investigated. The optimum pH for biosorption of Cd(II) onto WAS was found to be pH 5.0 and the quantitative removal of Cd(II) ions was achieved in 30 min. The kinetic study showed that the biosorption process followed the pseudo-second-order rate. Experimental data were analyzed by Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models. Desorption studies were carried out using HCl solution.


2012 ◽  
Vol 217-219 ◽  
pp. 862-865
Author(s):  
Li Jun Wang ◽  
Hua Yong Zhang ◽  
Lu Yi Zhang

The feasibility of using honeycomb-cinder slag as an adsorbent for phosphate removal from aqueous solution was investigated in batch experiments as a function of initial pH, contact time, adsorbent dose, and solution temperature. The results indicated that the solution pH significantly influenced the phosphate adsorption; 1440 min was enough to reach equilibrium for any concentration. Langmuir isotherm model gave well fit for phosphate adsorption, and the adsorption process followed pseudo second-order model. Desorption study exhibited that the phosphate adsorption on the honeycomb-cinder slag is not completely reversible. Results showed that honeycomb-cinder slag could be used as an adsorbent to uptake phosphate from wastewater.


2021 ◽  
Author(s):  
SEDA KARAYÜNLÜ BOZBAS ◽  
Begüm Canan Yıldız Aras ◽  
Muhammed Karabulut ◽  
Asgar Kayan

Abstract A Schiff base tin (IV) compound was synthesized by reactions between 2-((E)-(p-tolylimino)methyl)phenol (TIMPH) and butyltin trichloride in 2:1 mole ratio in ethanol at room temperature. [SnBuCl3(TIMPH)2] was characterized by FT-IR, 1H-NMR, 13C-NMR spectroscopy, elemental analysis, and mass spectrometry. Optimization of Murexide dye from aqueous solution was performed by examining; effect of contact time, initial pH, adsorbent amount, initial dye concentration and temperature on the tin adsorbent. The highest adsorption recovery value of was 98.00% and the adsorption capacity was 248.8 mg/g at the end of 20 minutes at 100 mg/L dye concentration while the temperature was 25°C and the pH was 3. Langmuir, Freundlich, and Temkin adsorption isotherms were calculated at 25 ºC. The highest R2 value was found 0.099 for the Langmuir isotherm model. The adsorption characteristics of murexide dye showed that adsorption kinetic obeyed the pseudo-second-order kinetics, and the thermodynamic data suggested the spontaneous and exothermic process.


2016 ◽  
Vol 74 (12) ◽  
pp. 2946-2957 ◽  
Author(s):  
Shixiang Wang ◽  
Yong Liu ◽  
Qin Fan ◽  
Anlan Zhou ◽  
Lu Fan ◽  
...  

An environmental friendly and economic natural biopolymer-sodium humate (HA-Na) was used to capture Hg(II) from aqueous solutions, and the trapped Hg(II) (HA-Na-Hg) was then removed by aluminium coagulation. The best Hg(II) capturing performance (90.60%) was observed under the following conditions: initial pH of 7.0, coagulation pH of 6.0, HA-Na dosage of 5.0 g L−1, Al2(SO4)3.18H2O dosage of 4.0 g L−1, initial Hg(II) concentration of 50 mg L−1 and capturing time of 30 min. The HA-Na compositions with the molecular weight beyond 70 kDa showed the most intense affinity toward Hg(II). The results showed that the reaction equilibrium was achieved within 10 min (pH 7.0), and could be well fitted by the pseudo-second-order kinetics model. The capturing process could be well described by the Langmuir isotherm model and the maximum capturing capacity of Hg(II) was high up to 9.80 mg g−1 at 298 K (pH 7.0). The Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis showed that the redox reaction between Hg(II) and HA-Na and the coordination reaction of carboxyl and hydroxy groups of HA-Na with Hg(II) were responsible for Hg(II) removal. The successive regeneration experiment showed that the capturing efficiency of humates for Hg(II) was maintained at about 51% after five capture-regeneration recycles.


2012 ◽  
Vol 9 (3) ◽  
pp. 1457-1480 ◽  
Author(s):  
R. Bhaumik ◽  
N. K. Mondal ◽  
B. Das ◽  
P. Roy ◽  
K. C. Pal ◽  
...  

A new medium, eggshell powder has been developed for fluoride removal from aqueous solution. Fluoride adsorption was studied in a batch system where adsorption was found to be pH dependent with maximum removal efficiency at 6.0. The experimental data was more satisfactorily fitted with Langmuir isotherm model. The kinetics and the factor controlling adsorption process fully accepted by pseudo-second-order model were also discussed. Eawas found to be 45.98 kJmol-1by using Arrhenius equation, indicating chemisorption nature of fluoride onto eggshell powder. Thermodynamic study showed spontaneous nature and feasibility of the adsorption process with negative enthalpy (∆H0) value also supported the exothermic nature. Batch experiments were performed to study the applicability of the adsorbent by using fluoride contaminated water collected from affected areas. These results indicate that eggshell powder can be used as an effective, low-cost adsorbent to remove fluoride from aqueous solution as well as groundwater.


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