Efficiency of Adsorption of Wastewater Containing Uranium by Fly Ash

2013 ◽  
Vol 639-640 ◽  
pp. 1295-1299 ◽  
Author(s):  
Shi You Li ◽  
Shui Bo Xie ◽  
Cong Zhao ◽  
Ya Ping Zhang ◽  
Jin Xiang Liu ◽  
...  

The effects of pH, different initial concentrations of uranium and adsorption time were investigated to study the properties of the sorption of uranium by fly ash. The results show that pH value is the major factor of dominating adsorption rate. The highest adsorption capacity was obtained at pH 5 and the adsorption time was 60 minutes. The increasing of initial uranium concentration resulted in the decreasing of U removal rate and the increasing of adsorption quantity, and the maximum adsorption capacity was 8.38mg/g. The adsorption behavior accorded with both the Freundlich and Langmuir isotherms.

2021 ◽  
Vol 13 (8) ◽  
pp. 1512-1520
Author(s):  
MiaoSen Zhang ◽  
SiYang Wang ◽  
Zheng Hu ◽  
RunZe Zhang ◽  
XiaoLi Wang

China is a big coal producing country, there are a lot of coal gangue piled up. The zeolite X was synthesized by alkali melting and hydrothermal method based on the coal gangue from Chifeng city, Inner Mongolia. The obtained zeolite X sample is characterized by X-ray diffraction, SEM, EDS spectrum and IR which showed the X zeolite is an octahedral structure with complete crystal shape and uniform grain size. The results of BET showed the specific surface area of zeolite X is 354.8 m2/g and the minimum pore size is 3.8 nm which indicated that the zeolite X belongs to mesoporous materials. The adsorption conditions of the zeolite X adsorbent on copper ions were optimized. A solution containing Cu2+ ions with an initial concentration of 300 mg/L was added to the zeolite X with a dosage of 0.1 g and the initial pH value of the solution was adjusted to 6. Then the solution was oscillated for 120 min at 225 r/min. The maximum adsorption capacity and removal rate were 148.6 mg/g and 99.1%, respectively. The adsorption mechanism was discussed by adsorption kinetics and thermodynamics. The quasi-second order kinetic equation can be well used to describe the adsorption kinetics of zeolite X to Cu2+ (R2 = 0.9994) and Langmuir can well describe the adsorption behavior of zeolite X to Cu2+ (R2 = 0.9995) which showed the adsorption is a monolayer of chemical adsorption. The adsorption capacity of zeolite X to Cu2+ is about 4.0 times that of coal gangue, indicating that the zeolite X has good adsorption capacity.


2018 ◽  
Vol 36 (7-8) ◽  
pp. 1456-1469 ◽  
Author(s):  
Fang Liu ◽  
Kanggen Zhou ◽  
Quanzhou Chen ◽  
Aihe Wang ◽  
Wei Chen

The magnetic ferrites were synthesized at ambient temperature through the precipitation method in aqueous solution at varying pH values and were used as novel adsorbents for heavy metal-containing wastewater treatment. The magnetic ferrites were applied for the removal of Cd(II) ion from wastewater. The synthesized magnetic ferrites were characterized by settling velocity, X-ray diffraction, scanning electron microscopy, laser particles size analyzer, and vibrating sample magnetometer. The effects of pH value and contact time on the adsorption process were investigated. The magnetic ferrites had a saturation magnetization value of 82.30 emu/g and a settling velocity of 2%, indicating easy separation from aqueous solution under magnetic field. The adsorption of Cd(II) onto the magnetic ferrites followed the pseudo-second-order kinetics and the Langmuir isotherm model. The most suitable pH condition for the synthesis of magnetic ferrite with optimal Cd(II) adsorption capacity was 9.0, and a maximum adsorption capacity of 160.91 mg/g for Cd(II) ions can be achieved. Based on the cost analysis, the magnetic ferrite was a cost-effective adsorbent for Cd-containing wastewater treatment.


Konversi ◽  
2013 ◽  
Vol 2 (2) ◽  
pp. 1
Author(s):  
Mardhiyah Nadir ◽  
Marlinda Marlinda

Proses produksi biodiesel menimbulkan hasil samping crude glycerol sekitar 10% (w/w). Kadar gliserol dalam crude tersebut masih rendah karena masih mengandung pengotor sehingga perlu pemurnian agar dapat dimanfaatkan untuk bahan baku industri, misalnya industri obat dan kosmetika. Penelitian ini bertujuan meningkatkan kemurnian crude glycerol dengan metoda adsorpsi menggunakan fly ash dan menentukan kapasitas adsorpsinya. Data kesetimbangan adsorpsi asam lemak bebas dalam gliserol didekati dengan Model Langmuir dan Freundlich. Berat adsorben pada penelitian ini berturut- turut 2,5; 5,0; 7,5 dan 10 gram dengan waktu adsropsi bervariasi selama 40, 50, 60 , 70 dan 80 menit. Hasil pemurnian dianalisa kandungan asam lemak bebas dan gliserol. Kadar asam lemak bebas dapat teradsorpsi maksimum ketika pemurnian menggunakan 10 g adsorben selama 60 menit. Kapasitas maksimum adsorpsi sebesar 5,186x10-4 mmol/g. Berdasarkan nilai koefisien korelasi (R2) menunjukkan bahwa model Langmuir dan Freundlich cocok untuk penelitian ini. Kata kunci : adsorpsi, Crude glycerol, biodiesel, fly ash Crude glycerol is a byproduct of the production of biodiesel produced about 10% (w/w) of the weight of biodiesel . Crude glycerol still contains many impurities that cause low levels of glycerol into that utilization is not maximized . Purified glycerol widely used in several fields such as manufacture of drugs and cosmetic. Therefore, there needs to be a process of purification in order to obtain higher levels of glycerol . This study aims to perform the purification of crude glycerol to determine the method of adsorption and adsorption capacity of fly ash. Adsorption processes associated with the equilibrium adsorption performed at constant temperature (isotherms) to obtain the maximum adsorption capacity data. Langmuir and Freundlich models proposed to interpret the data of adsorption equilibrium of free fatty acids in the glycerol . This research was carried out by varying the mass of adsorbent 2.5g , 5.0g , 7.5g and 10g, and the adsorption time 40, 50, 60, 70 and 80 minutes. Purification of crude glycerol were analyzed using analysis of free fatty acids and glycerol analysis. The results showed that 10g Mass adsorbent and adsorption time of 60 minutes can reduce Free Fatty Acid (FFA) that glycerol levels increased . The maximum adsorption capacity of 5.186 x10- 4 mmol/g. Based on the value of the correlation coefficient (R2) indicates that the Langmuir and Freundlich models are suitable for this study. Keywords: adsorption, crude glycerol, biodiesel, fly ash  


2014 ◽  
Vol 535 ◽  
pp. 671-674 ◽  
Author(s):  
Lei Ding ◽  
Bei Gang Li ◽  
Jing Mi

Fly ash/CeO2 composite adsorbent (FA/CeO2) was prepared by HCl treatment and precipitation method using a low-cost waste fly ash (FA) as the raw material and used for the removal of Congo Red (CR) from aqueous solution. Effects of important parameters such as contact time, initial dye concentration, pH value and temperature were explored. Adsorption equilibrium and isotherms were investigated. The adsorption of CR onto FA/CeO2 is a fast process and to achieve a basic balance in 30 minutes. The removal of CR is strongly pH-dependent. FA/CeO2 is an effective adsorbent for the CR removal with removal rate of 98.8% when initial CR concentration is 1000 mg/L. The experimental isotherm data were analyzed using Langmuir and Freundlich isotherm models. The results revealed that the adsorption behavior of CR on FA/CeO2 fitted well with the Langmuir model at different temperatures. The maximum adsorption capacity obtained by Langmuir model is 232.56 mg/g which is nearly consistent with the actual adsorption value of 230.01 mg/g at 298K. The Adsorption amount decreases with increasing temperature, but the variation of the amplitude is very small.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2741
Author(s):  
Pengcheng Lv ◽  
Ruihong Meng ◽  
Zhongyang Mao ◽  
Min Deng

In this study, the hydrated sodium aluminosilicate material was synthesized by one-step hydrothermal alkaline desilication using fly ash (FA) as raw material. The synthesized materials were characterized by XRD, XRF, FT-IR and SEM. The characterization results showed that the alkali-soluble desilication successfully had synthesized the sodium aluminosilicate crystalline (N-A-S-H) phase of sodalite-type (SOD), and the modified material had good ionic affinity and adsorption capacity. In order to figure out the suitability of SOD as an adsorbent for the removal of ammonium and phosphorus from wastewater, the effects of material dosing, contact time, ambient pH and initial solute concentration on the simultaneous removal of ammonium and phosphorus are investigated by intermittent adsorption tests. Under the optimal adsorption conditions, the removal rate of ammonium was 73.3%, the removal rate of phosphate was 85.8% and the unit adsorption capacity reached 9.15 mg/L and 2.14 mg/L, respectively. Adsorption kinetic studies showed that the adsorption of ammonium and phosphorus by SOD was consistent with a quasi-secondary kinetic model. The adsorption isotherm analysis showed that the equilibrium data were in good agreement with the Langmuir and Freundlich model. According to thermodynamic calculations, the adsorption of ammonium and phosphorus was found to be a heat-absorbing and spontaneous process. Therefore, the preparation of SOD by modified FA has good adsorption properties as adsorbent and has excellent potential for application in the removal of contaminants from wastewater.


Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 63
Author(s):  
Maria Harja ◽  
Gabriela Buema ◽  
Nicoleta Lupu ◽  
Horia Chiriac ◽  
Dumitru Daniel Herea ◽  
...  

Fly ash/magnetite material was used for the adsorption of copper ions from synthetic wastewater. The obtained material was characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) surface area, and vibrating sample magnetometer (VSM). Batch adsorption experiments were employed in order to investigate the effects of adsorbent dose, initial Cu (II) concentration and contact time over adsorption efficiency. The experimental isotherms were modeled using Langmuir (four types of its linearization), Freundlich, Temkin, and Harkins–Jura isotherm models. The fits of the results are estimated according to the Langmuir isotherm, with a maximum adsorption capacity of 17.39 mg/g. The pseudo-second-order model was able to describe kinetic results. The data obtained throughout the study prove that this novel material represents a potential low-cost adsorbent for copper adsorption with improved adsorption capacity and magnetic separation capability compared with raw fly ash.


2014 ◽  
Vol 1044-1045 ◽  
pp. 215-218
Author(s):  
Xian Huan Qiu ◽  
Hai Yu ◽  
Peng Fei Deng

In the presence of acetic acid, the effects of pH, processing time, addition of Fe2+ and H2O2 on dye wastewater treatment were studied. Experimental results showed that in the presence of acetic acid, when the pH value was 4, the processing time was 30.0min, addition of ferrous sulfate was 4.8g/L, and addition of hydrogen peroxide was 56mL/L, the treatment effect was the best, COD removal rate reached 51.0%. Further studied of the effect of the presence of acetic acid on Fenton’s oxidation of dye wastewater, the results showed that without of acetic acid, the COD removal rate was higher than that with acetic acid. And the effect of Fenton's reagent on oxidation of dye substances was interfered by the presence of acetic acid.


2014 ◽  
Vol 70 (4) ◽  
pp. 678-684 ◽  
Author(s):  
Jun Chen ◽  
Xiaoqin Hong ◽  
Yongteng Zhao ◽  
Qianfeng Zhang

Exfoliated polyaniline/montmorillonite (PANI/MMT) composites with nanosheet structure were successfully prepared by in situ chemical oxidation polymerization with MMT platelets as the scaffold. Amphoteric polymer, (2-methacryloyloxyethyl)trimethyl ammonium chloride and methacrylate acid copolymer, was used to modify montmorillonite and a large number of carboxylic acids were introduced on the surface of the clay platelets, which can be used as a dopant of PANI and play a ‘bridge’ role to combine PANI with clay. Adsorption experiments were carried out to study the effects of pH, contact time, Cr(VI) concentration, adsorbent dose and temperature. The adsorption of Cr(VI) on the PANI/MMT was highly pH dependent and the adsorption kinetics followed a pseudo-second-order model. The Langmuir isothermal model described the adsorption isotherm data well and the maximum adsorption capacity increased with the increase in temperature. Thermodynamic investigation indicated that the adsorption process is spontaneous, endothermic and marked with an increase in randomness at the adsorbent – liquid interface. The maximum adsorption capacity of the PANI/MMT composites for Cr(VI) was 308.6 mg/g at 25 °C. The excellent adsorption characteristic of exfoliated PANI/MMT composites will render it a highly efficient and economically viable adsorbent for Cr(VI) removal.


2011 ◽  
Vol 239-242 ◽  
pp. 2310-2316 ◽  
Author(s):  
Chun Mei Niu ◽  
Shao Ying Li ◽  
Dong Huang

Crosslinked Carboxymethyl Konjac Glucomannan(CMKGM) with substitution degrees ofcarboxymethyl group(DS)0.265, 0.457 and 0.586 were prepared through reaction of monochloroacetic acid, konjac glucomannan(KGM) and epichlorohydrin and used to adsorb Cu(II) from the aqueous solutions of copper nitrate. The effects of pH, adsorbent dose, initial concentration of Cu(II), adsorption time and temperature on adsorption capacity were investigated. The results showed that adsorption capacity increased with an increasing DS of the carboxymethyl groups. Equilibrium adsorption time was 20 min or so and was independent on DS. The adsorption followed Langmuir isotherm equation. Ligand ion adsorption between carboxymethyl group and Cu(II) was thought to be predominate in the process of adsorption according to the relationship between DS and thermodynamic parameters. CMKGM can be used as cheaper and more effective adsorbents.


2018 ◽  
Vol 5 (1) ◽  
pp. 171662 ◽  
Author(s):  
Bin Feng ◽  
Wenzhong Shen ◽  
Liyi Shi ◽  
Shijie Qu

Owing to the unique microporous structure and high specific surface area, porous carbon could act as a good carrier for functional materials. In this paper, polyacrylonitrile (PAN)-based porous carbon materials (PPC-0.6-600, PPC-0.8-600, PPC-0.6-800 and PPC-0.8-800) were prepared by heating KOH at 600°C and 800 o C for the removal of Cr(VI) from aqueous solution. The adsorbent was characterized by the techniques of Fourier transform infrared spectroscopy (FT-IR), elementary analysis, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and N 2 adsorption techniques. The results showed that the adsorption capacity increased with decreasing pH value of the initial solution. The adsorption capacity of Cr(VI) on PPC-0.8-800 was much greater than that on other materials, and maximum adsorption capacity were calculated to be 374.90 mg g −1 . Moreover, PPC-0.8-800 had superior recyclability for the removal of Cr(VI) from wastewater, about 82% of its initial adsorption capacity was retained even after five cycles. The result of kinetic simulation showed that the adsorption of Cr(VI) on the PAN-based porous carbon could be described by pseudo-second-order kinetics. The adsorption process was the ionic interaction between protonated amine groups of PPC and HCrO 4 - ions.


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