scholarly journals Mild Hydrothermal Synthesis of 11Å-TA from Alumina Extracted Coal Fly Ash and Its Application in Water Adsorption of Heavy Metal Ions (Cu(II) and Pb(II))

Author(s):  
Jingjie Yang ◽  
Hongjuan Sun ◽  
Tongjiang Peng ◽  
Li Zeng ◽  
Xin Zhou

Non-biodegradable copper (Cu) and lead (Pb) contaminants in water are highly toxic and have series adverse effects. Therefore, it is very important to extract heavy metals from wastewater before it is discharged into the environment. Adsorption is a cost-effective alternative method for wastewater treatment. Choosing a low-cost adsorbent can help reduce the cost of adsorption. In this study, conversion of reside after extracting aluminum (REA) produced by sub-molten salt method transform high-alumina coal fly ash (CFA) into 11Å-tobermorite to adsorb Cu(II) and Pb(II) from aqueous solutions at room temperature. The synthesis of the adsorbent was confirmed using scanning electron microscope (SEM), X-ray diffractometer (XRD) and Brunauer–Emmett–Teller (BET) method surface analysis. To study the adsorption characteristics, factors such as initial Cu(II) and Pb(II) concentration, pH, contact time, adsorption characteristics and temperature were investigated in batch mode. The maximum adsorption capacity of Cu(II) and Pb(II) was 177.1 mg·g−1 and 176.2 mg·g−1, respectively. The Langmuir adsorption model was employed to better describe the isothermal adsorption behavior and confirm the monolayer adsorption phenomenon. The pseudo-second-order kinetic model was used to highlight Cu(II) and Pb(II) adsorption kinetics. Thermodynamic analysis indicated the removal Cu(II) and Pb(II) by TA-adsorbent was a nonspontaneous and exothermic reaction. The obtained results are of great significance to the conversion of industrial waste to low-cost adsorbent for Cu(II) and Pb(II) removal from water.

2020 ◽  
Vol 81 (10) ◽  
pp. 2176-2188
Author(s):  
Zekun Yang ◽  
Hailing Wang ◽  
Huiming Sun ◽  
Haifeng Tang ◽  
Guangze Nie

Abstract In order to reduce the environmental impact of benzoic acid (BA), molecular imprinted polymers based on attapulgite were facilely prepared by molecular imprinted technique. The samples were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and thermal gravimetric analysis. The adsorption performance, regeneration stability, and competitive selectivity of BA by benzoic acid-surface molecular imprinted polymers (BA-MIP) were systematically investigated by experiments. For this material, it has a high adsorption capacity of 41 mg/g and an equilibrium adsorption time of about 150 min. Compared with non-imprinted polymers, BA-MIP has a higher adsorption capacity for BA, and the dynamic adsorption behavior of BA by both of them conforms to the quasi-second-order kinetic model. The Langmuir adsorption isotherm equation was fitted the isothermal adsorption experiment. The thermodynamic analysis shows that the adsorption process is an exothermic reaction. The adsorption capacity of BA first increases and then decreases with an increase in pH, and the maximum adsorption capacity is reached at pH = 5. BA-MIP also has excellent selective adsorption capacity and regeneration stability for BA.


2013 ◽  
Vol 864-867 ◽  
pp. 1732-1740
Author(s):  
Xiao Xu ◽  
Qiang Yang ◽  
Chao Yang Wang

Cobalt ions, which are commonly found in low concentrations in industrial wastewater, are toxic, biocumulative, and hard to degrade. Therefore, the removal of these heavy metal ions from wastewater is highly important. The removal of Co (II) from aqueous solutions using untreated and alkali-modified coal fly ash was studied. The results for untreated fly ash show that the pseudo-second-order kinetic equation better fits the observed adsorption progress. The Langmuir and Freundlich isotherms could describe the reaction efficiently, and the maximum adsorption capacity for Co (II) was 237 mg·g-1at 20°C. Pretreating the fly ash with an alkali solution decreases the adsorption capability, possibly by destroying the zeolite structure. When the ratio of the fly ash dose and Co (II) concentration is between 40 and 60, the removal rate of Co (II) at a concentration of 20 mg·L-1reaches 99.95%.


2020 ◽  
Vol 9 (1) ◽  
pp. 770-782
Author(s):  
Tianpeng Li ◽  
Jing Fan ◽  
Tingting Sun

AbstractA novel porous ceramsite was made of municipal sludge, coal fly ash, and river sediment by sintering process, and the performance of batch and fixed-bed column systems containing this material in the removal of acid red G (ARG) dye from aqueous solutions was assessed in this study. The results of orthogonal test showed that sintering temperature was the most important determinant in the preparation of porous ceramsite, and it possesses developed pore structure and high specific surface area. Batch experiment results indicated that the adsorption process of ARG dye toward porous ceramsite was a spontaneous exothermic reaction, which could be better described with Freundlich–Langmuir isotherm model (R2 > 0.992) and basically followed the pseudo-first-order kinetic equation (R2 > 0.993). Column experiment results showed that when the porous ceramsite was used as packing material, its adsorption capacity was roughly improved by 3.5 times compared with that in batch system, and the breakthrough behavior was simulated well with Yoon–Nelson model, with R2 > 0.954. This study suggested that the novelty man-made porous ceramsite obtained from solid wastes might be processed as a certain cost-effective treatment material fit for the dye removal in aqueous solutions.


2010 ◽  
Vol 81 (4) ◽  
pp. 320-332 ◽  
Author(s):  
Shifeng Dai ◽  
Lei Zhao ◽  
Suping Peng ◽  
Chen-Lin Chou ◽  
Xibo Wang ◽  
...  

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2682
Author(s):  
Gyuhyeon Kim ◽  
Young-Mo Kim ◽  
Su-Min Kim ◽  
Hyun-Uk Cho ◽  
Jong-Moon Park

In this study, magnetic steel slag biochar (MSSB) was synthesized from low-cost steel slag waste to investigate the effectiveness of steel slag biochar composite for NH4-N removal and magnetic properties in aqueous solution. The maximum adsorption capacity of NH4-N by MSSB was 4.366 mg/g according to the Langmuir model. The magnetic properties of MSSB indicated paramagnetic behavior and a saturation magnetic moment of 2.30 emu/g at 2 Tesla. The NH4-N adsorption process was well characterized by the pseudo-second order kinetic model and Temkin isotherm model. This study demonstrated the potential of magnetic biochar synthesized from steel slag waste for NH4-N removal in aqueous solution.


Author(s):  
Virendra Kumar Yadav ◽  
R Suriyaprabha ◽  
Gajendra Kumar Inwati ◽  
Nitin Gupta ◽  
Bijendra Singh ◽  
...  

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 3575-3595
Author(s):  
Wanting Li ◽  
Ruifeng Shan ◽  
Yuna Fan ◽  
Xiaoyin Sun

Desethyl-atrazine (DEA) is a metabolite of atrazine that exerts a considerable influence on the environment. In this study, tall fescue biochar was prepared by pyrolysis at 500 °C, and batch experiments were conducted to explore its effect on the adsorption behavior of DEA in red soil, brown soil, and black soil. The addition of biochar increased the equilibrium amount of DEA adsorption for the three soil types. A pseudo-second-order kinetic model most closely fit the DEA adsorption kinetics of the three soils with and without biochar, with a determination coefficient (R2) of 0.962 to 0.999. The isothermal DEA adsorption process of soils with and without biochar was optimally described by the Freundlich and Langmuir isothermal adsorption models with R2 values of 0.98 and above. The DEA adsorption process in the pristine soil involved an exothermic reaction, which became an endothermic reaction after the addition of biochar. Partitioning was dominant throughout the entire DEA adsorption process of the three pristine soils. Conversely, in soils with biochar, surface adsorption represented a greater contribution toward DEA adsorption under conditions of low equilibrium concentration. The overall results revealed that the tall fescue biochar was an effective adsorbent for DEA polluted soil.


2018 ◽  
Vol 154 ◽  
pp. 01037 ◽  
Author(s):  
Agus Taufiq ◽  
Pratikno Hidayat ◽  
Arif Hidayat

The removal of reactive dyes on modified coal fly ash has been investigated during a series of batch adsorption experiments. Physical characteristics of modified coal fly ash was characterized by Brunauer Emmett Teller (BET) surface area analysis, X-ray powder diffraction (XRD), Fourier transform infrared spectrophotometer (FT-IR), and scanning electron microscope (SEM). The effects of operational parameters such as initial dye concentration (50–200 mg/L), solution pH (4–10) and adsorbent dosage (50–200 mg/L) were studied. The adsorption experiments indicated that modified coal fly ash was effective in removing of Remazol Blue. The percentage removal of dyes increased while the modified fly ash dosage increased. The percentage removal of dyes increased with decreased initial concentration of the dye and also increased with amount of adsorbent used. The optimum of removal of dyes was found to be 94% at initial dye concentration 50 g/mL, modified fly ash dosage 250 g/mL, and pH of 2.0.


2020 ◽  
Vol 840 ◽  
pp. 57-63
Author(s):  
Dina Fitriana ◽  
Mudasir Mudasir ◽  
Dwi Siswanta

Adsorption of Pb(II) ions onto selective adsorbent of dithizone-immobilized coal fly ash (DCFA) from Holcim, Cilacap, Indonesia has been investigated in batch experiments. Prepared coal fly ash (CFA) modified by immobilization of dithizone previously were characterized by FT-IR and XRD. Several parameters influencing the adsorption of Pb(II) ions such as effect of pH, adsorbent dosage, contact time and initial concentration of ions on the efficiency of the adsorption were studied. The optimum condition of Pb(II) adsorption was found at pH 5, adsorbent dosage 0.1 g, contact time 60 min and initial Pb(II) ions concentration of 60 mg L–1. The adsorption kinetics of Pb(II) ions on DCFA was found to follow a pseudo-second-order kinetic model. The adsorption isotherm data were fitted to the Langmuir model. Kinetics and adsorption isotherm studies suggest that the capacity and affinity of the DCFA in adsorbing Pb(II) ions is significantly improved compared to those of non-immobilized activated coal fly ash (ACFA).


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