scholarly journals Adsorption and Reduction from Modified Polypyrrole Enhance Electrokinetic Remediation of Hexavalent Chromium-Contaminated Soil

2021 ◽  
Author(s):  
Jiangyuan Wang ◽  
Qiu Yu ◽  
Yi Zheng ◽  
Jing Li ◽  
Binquan Jiao ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Contaminated Soil ◽  
Electrokinetic Remediation ◽  
Batch Adsorption ◽  
Isothermal Model ◽  
Soil Adsorption ◽  
Monolayer Adsorption ◽  
Bet Analysis ◽  
Pseudo Second Order ◽  
Reaction Barriers

Abstract Heavy metal pollutant Cr(Ⅵ) in the environment will pose a severe threat to animal and human health. In this work, Fe3O4@PPy, Arg@PPy, and Arg/Fe3O4@PPy were prepared to enhance adsorption of Cr(Ⅵ) by doping Fe3O4 nanoparticles and amino radicals into the original PPy structure. Their characteristics were investigated by FTIR, SEM, EDS, BET analysis, and batch adsorption experiments. And they were used as permeable reaction barriers (PRB) to combine with electrokinetic remediation (EKR) to remediate Cr-contaminated soil. Adsorption experiment results showed that the maximum adsorption capacities of PPy, Fe3O4@PPy, Arg@PPy, and Arg/Fe3O4@PPy for Cr(Ⅵ) were 60.43 mg/g, 67.12 mg/g, 159.86 mg/g, and 141.50 mg/g, respectively. All of them followed the kinetic pseudo-second-order model and the Langmuir isothermal model with a monolayer adsorption behavior. In EKR/PRB system, the presence of Fe3O4@PPy, Arg@PPy, and Arg/Fe3O4@PPy obtained the higher Cr(Ⅵ) removal efficiency near the anode than that of the PPy, increasing by 74.60%, 26.04%, 68.64%, respectively. A strong electrostatic attraction between anion contaminants and protonated modified PPy and a reduction from Cr(Ⅵ) to Cr(Ⅲ) appeared in the EKR remediation process under acid conditions. This study opened up a prospect for applying modified PPy composites to treat heavy metal contaminated soil.

scholarly journals Biochar of Spent Coffee Grounds as Per Se and Impregnated with TiO2: Promising Waste-Derived Adsorbents for Balofloxacin

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2295
Author(s):  
Marwa El-Azazy ◽  
Ahmed S. El-Shafie ◽  
Hagar Morsy
Keyword(s):  
Adsorption Capacity ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Spent Coffee Grounds ◽  
Thermal Stabilities ◽  
Coffee Grounds ◽  
Bet Analysis ◽  
Pseudo Second Order ◽  
Set Up ◽  
Adsorption Desorption

Biochars (BC) of spent coffee grounds, both pristine (SCBC) and impregnated with titanium oxide (TiO2@SCBC) were exploited as environmentally friendly and economical sorbents for the fluroquinolone antibiotic balofloxacin (BALX). Surface morphology, functional moieties, and thermal stabilities of both adsorbents were scrutinized using SEM, EDS, TEM, BET, FTIR, Raman, and TG/dT analyses. BET analysis indicated that the impregnation with TiO2 has increased the surface area (50.54 m2/g) and decreased the pore size and volume. Batch adsorption experiments were completed in lights of the experimental set-up of Plackett-Burman design (PBD). Two responses were maximized; the % removal (%R) and the adsorption capacity (qe, mg/g) as a function of four variables: pH, adsorbent dosage (AD), BALX concentration ([BALX]), and contact time (CT). %R of 68.34% and 91.78% were accomplished using the pristine and TiO2@SCBC, respectively. Equilibrium isotherms indicated that Freundlich model was of a perfect fit for adsorption of BALX onto both adsorbents. Maximum adsorption capacity (qmax) of 142.55 mg/g for SCBC and 196.73 mg/g for the TiO2@SCBC. Kinetics of the adsorption process were best demonstrated using the pseudo-second order (PSO) model. The adsorption-desorption studies showed that both adsorbents could be restored with the adsorption efficiency being conserved up to 66.32% after the fifth cycles.

scholarly journals A study of atrazine adsorption by using the rice straw synthesized adsorbent

2018 ◽  
Vol 192 ◽  
pp. 03035
Author(s):  
Thachanan Samanmulya ◽  
Pawinee Deetae ◽  
Patthranit Wongpromrat
Keyword(s):  
Surface Area ◽  
Rice Straw ◽  
Elemental Analysis ◽  
Pore Volume ◽  
Second Order ◽  
Batch Adsorption ◽  
Physico Chemical ◽  
Bet Analysis ◽  
Rice Straw Biochar ◽  
Pseudo Second Order

This study focused on adsorption of atrazine in adsorbent synthesized from Rice Straw. Rice Straw biochar were used in the study as they exhibited significantly high adsorption capacity for pesticide. Briefly, rice straw was pyrolysis at 600°C under nitrogen then biochar was modified using H3PO4. Biochar were characterized for their physico-chemical characteristics. The elemental analysis of biochar was performed using CHNS Analysis. The surface area and pore volume of adsorbents were estimated using the Brunauer, Emmett, and Teller (BET Analysis). In parts of Batch adsorption experiments was performed in range of room temperature and were divided to 2 parts. Part 1: Study of the kinetics adsorption was investigated using two models, namely, the pseudo-first-order and the pseudo-second-order models. Part 2: study of Adsorption isotherms. The results of CHNS analysis shows the elemental analysis that 51.795% of C, 0.763% of H, 1.634% of N and 0.654 % of S and the result of BET Analysis shows the surface area is 372.4 m2/g and pore volume of adsorbents is 0.315 cm3. From plotting between qt(mg/g) and time (t) shows the dynamics of the adsorption of atrazine onto the biochar at 15 ppm of initial atrazine concentrations. In general, atrazine was adsorbed quickly around 1-30 min. This could be due to fast mass transfer of solute from the solution to surface of adsorbent s as a result of concentration gradient of the solute. The study of the kinetics adsorption showed that the pseudo-second-order model best described the adsorption which agrees with chemisorption as the rate controlling mechanism.

scholarly journals Char from Spent Tire Rubber: A Potential Adsorbent of Remazol Yellow Dye

2019 ◽  
Vol 5 (4) ◽  
pp. 76
Author(s):  
Nogueira ◽  
Matos ◽  
Bernardo ◽  
Pinto ◽  
Lapa ◽  
...  
Keyword(s):  
Experimental Data ◽  
Low Cost ◽  
Total Pore Volume ◽  
Batch Adsorption ◽  
Order Kinetic ◽  
Uptake Capacity ◽  
Experimental Conditions ◽  
Tire Rubber ◽  
Monolayer Adsorption ◽  
Pseudo Second Order

A char produced from spent tire rubber showed very promising results as an adsorbent of Remazol Yellow (RY) from aqueous solutions. Spent tire rubber was submitted to a pyrolysis process optimized for char production. The obtained char was submitted to chemical, physical, and textural characterizations and, subsequently, applied as a low-cost adsorbent for dye (RY) removal in batch adsorption assays. The obtained char was characterized by relatively high ash content (12.9% wt), high fixed-carbon content (69.7% wt), a surface area of 69 m2/g, and total pore volume of 0.14 cm3/g. Remazol Yellow kinetic assays and modelling of the experimental data using the pseudo-first and pseudo-second order kinetic models demonstrated a better adjustment to the pseudo-first order model with a calculated uptake capacity of 14.2 mg RY/g char. From the equilibrium assays, the adsorption isotherm was fitted to both Langmuir and Freundlich models; it was found a better fit for the Langmuir model to the experimental data, indicating a monolayer adsorption process with a monolayer uptake capacity of 11.9 mg RY/g char. Under the experimental conditions of the adsorption assays, the char presented positive charges at its surface, able to attract the deprotonated sulfonate groups (SO3−) of RY; therefore, electrostatic attraction was considered the most plausible mechanism for dye removal.

scholarly journals Efficient removal of cadmium (II) ions from aqueous solution by CoFe2O4/chitosan and NiFe2O4/chitosan composites as adsorbents

2018 ◽  
Vol 78 (11) ◽  
pp. 2297-2307 ◽  
Author(s):  
Ashraf Homayonfard ◽  
Mahsasadat Miralinaghi ◽  
Reza Haji Seyed Mohammad Shirazi ◽  
Elham Moniri
Keyword(s):  
Competitive Adsorption ◽  
Aqueous Media ◽  
Batch Adsorption ◽  
Practical Application ◽  
Efficient Removal ◽  
Monolayer Adsorption ◽  
Pseudo Second Order ◽  
One Step ◽  
Study Support ◽  
Cobalt And Nickel

Abstract Magnetically recoverable chitosan based spinel cobalt and nickel ferrite (CS/CoFe2O4 and CS/NiFe2O4, respectively) composites were successfully prepared in one step. A series of batch adsorption experiments indicated that the removal of toxic Cd(II) ions by the as-obtained composites as adsorbents was pH-dependent, rapid, proficient, better fitted to pseudo-second-order kinetics model and Langmuir monolayer adsorption isotherm model. Compared to the naked particles, magnetic bio-polymer composites exhibited promoted adsorption capacity. Competitive adsorption studies in binary solutions illustrated preferable selectivity of adsorbents toward Cd(II) ions in the presence of co-existing cations. More importantly, CS/CoFe2O4 and CS/NiFe2O4 had a satisfactory practical application in the removal of Cd(II) from real groundwater spiked with cadmium. The exhausted adsorbents could be regenerated efficiently by 0.5 M HNO3. The results from this study support that CS/CoFe2O4 and CS/NiFe2O4 prove excellent adsorption behavior for the removal of Cd(II) ions from aqueous media.

scholarly journals Talisay (Terminalia catappa) seed husk biochar for adsorption of lead (II) ions in artificially contaminated soil

2019 ◽  
Vol 268 ◽  
pp. 04011 ◽  
Author(s):  
Joric John Canlas ◽  
Jenika Cris Go ◽  
Ardith Clarisse Mendoza ◽  
Maria Natalia Dimaano
Keyword(s):  
Heavy Metal ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Isotherm Models ◽  
Sem Images ◽  
Terminalia Catappa ◽  
Heavy Metal Sorption ◽  
Different Temperatures ◽  
Pseudo Second Order ◽  
Seed Husk

Lead, a commonly found heavy metal in contaminated soil, is highly mobilized in acidic conditions resulting to rapid soil leaching. This study investigated the effectiveness of biochar derived from Talisay (Terminalia catappa) seed husks employing the long-term immobilization of Lead in an artificially contaminated soil using simulated acid rain water meant for 100 years of rain with 5% amendment rate. Before immobilization, the heating temperatures were varied at 400, 500 and 600°C to determine its optimal pyrolysis temperature. The biochar was pyrolyzed under three different temperatures: with 1-hour residence time. SEM images revealed that the degree of porosity of the biochar produced increased as the temperature increased. In addition, the biochar produced at 600°C has the highest % fixed carbon and % elemental carbon indicating stability. It then shows that Talisay seed husks are feasible materials for biochar production that can be used for the amendment of lead contaminated soil. The Freundlich and Langmuir models were used to describe the heavy metal sorption equilibrium of the biochar. Results showed that the biochar best fitted the pseudo-second-order models and Langmuir isotherm models and that the biochar displayed a favorable adsorption. Also, the immobilization experiment showed that the soil amended with biochar immobilized Pb decreasing its concentration by 99.47%. Therefore, the produced biochar is suitable for Pb remediation in contaminated soils.

scholarly journals Preparation of Calixarene-PI Nanofibers and Application as a Selective Adsorbent for Heavy Metal Ions

2018 ◽  
Vol 13 (1) ◽  
pp. 155892501801300
Author(s):  
Xuchen Tao ◽  
Quan Feng ◽  
Hui He
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Adsorption Kinetics ◽  
Heavy Metal Ions ◽  
Selective Adsorption ◽  
Physical Adsorption ◽  
Second Order ◽  
Kinetics Model ◽  
Isothermal Model ◽  
Pseudo Second Order

In order to utilize the adsorption selectivity of calixarenes towards heavy metal ions, calixarene functionalized polyimide (Calix-PI) fibers were prepared by three main synthesis procedures including preparation of the calixarene polyamide acid (Calix-PAA) spinning solution via amidation, fabrication of the Calix-PAA fibers by electrospinning, and preparation of the Calix-PI fibers via thermal imidization on the Calix-PAA fibers. The Calix-PI fibers were characterized by Fourier transform infrared spectroscopy, scanning electronic microscopy and thermogravimetric analysis. The Calix-PI fibers display selective adsorption on Pb(II), which is fit with the pseudo-second-order adsorption kinetics model and the Freundlich adsorption isothermal model. The rate constant of the pseudo-second-order adsorption kinetics model and the maximum Pb(II) uptake have all been calculated. The practical adsorption of Pb(II) on the Calix-PI fibers is mainly attributed to the monolayer chemical adsorption and slightly depended on the physical adsorption.

Isotherm Studies of Methylene Blue Adsorption onto Potassium Salts-Modified Textile Sludge

2015 ◽  
Vol 74 (7) ◽  
Author(s):  
Tang Shu Hui ◽  
Muhammad Abbas Ahmad Zaini
Keyword(s):  
Methylene Blue ◽  
Surface Area ◽  
Activated Carbons ◽  
Isotherm Model ◽  
Bet Surface Area ◽  
Batch Adsorption ◽  
Potassium Salts ◽  
Monolayer Adsorption ◽  
Bet Analysis ◽  
Textile Sludge

In the present work, the adsorption of methylene blue from aqueous solution by textile sludge activated with potassium salts and a composite-KI, KCl, K2SO4 and KOH+KCl-was investigated. The impregnation ratio for all activating agents was set at 1:1 and the impregnated textile sludge samples were activated at 500oC for 1h in a furnace. The specific surface area of the activated carbon (AC) was evaluated using BET analysis. The BET surface area varied from 78.8 to 321m2/g, where it decreased in the order of K2SO4-AC > KCl-AC > KI-AC > KOH+KCl-AC. Under room temperature condition and a shaking time of 72h, the batch adsorption results show that the minimum and maximum adsorption capacities were recorded as 39.1 and 85.0mg/g for textile sludge activated with KCl and KI, respectively. Langmuir isotherm model gave the best fit to adsorption equilibrium compared to Freundlich isotherm model indicating a monolayer adsorption at homogeneous sites on the adsorbent. The Langmuir mechanism yielded a maximum monolayer adsorption capacity of 90.9mg/g. Among the four prepared activated carbons, textile sludge activated with potassium iodide (KI-AC) gave the best performance on the adsorption of methylene blue. 

scholarly journals Removal of aqueous Cr(VI) by magnetic biochar derived from bagasse

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Meina Liang ◽  
Yanmei Ding ◽  
Qing Zhang ◽  
Dunqiu Wang ◽  
Huanhuan Li ◽  
...  
Keyword(s):  
Adsorption Process ◽  
Amorphous Structure ◽  
Batch Adsorption ◽  
High Adsorption ◽  
Magnetic Biochar ◽  
Adsorption Performance ◽  
Monolayer Adsorption ◽  
Before And After ◽  
Pseudo Second Order ◽  
Cr Concentration

AbstractWe prepared a novel adsorbent functionalized by bagasse magnetic biochar (BMBC). To study the removal behaviors and mechanisms of Cr(VI) by BMBC, batch adsorption experiments were conducted by modifying variables, such as pH, adsorption time, BMBC dosages, initial Cr concentration, co-existing ions, and ionic strength, and characterizing BMBC before and after Cr(VI) adsorption. BMBC was primarily composed of Fe2O3 and Fe3O4 on bagasse boichar with an amorphous structure. The specific surface area of BMBC was 81.94 m2 g−1, and the pHpzc of BMBC was 6.2. The fabricated BMBC showed high adsorption performance of Cr(VI) in aqueous solution. The maximum Cr(VI) adsorption capacity of BMBC was 29.08 mg g−1 at 25 ºC, which was much higher than that of conventional biochar sorbents. The adsorption process followed pseudo-second-order kinetics and could be explained by the involvement of the Langmuir isotherm in monolayer adsorption. The crystalline structure of Fe3O4 in the BMBC changed slightly during the adsorption process; Fe3O4 improved the adsorption of Cr(VI) on BMB. The desorption capacity of Cr(VI) was 8.21 mg g−1 when 0.2 mol L−1 NaOH was used as the desorption solution. After being reused three times, the removal efficiency is still as high as 80.36%.

Adsorption studies of Cu(II) onto biopolymer chitosan and its nanocomposite 5%bentonite/chitosan

2016 ◽  
Vol 73 (9) ◽  
pp. 2199-2210 ◽  
Author(s):  
Hamou Moussout ◽  
Hammou Ahlafi ◽  
Mustapha Aazza ◽  
Omar Zegaoui ◽  
Charaf El Akili
Keyword(s):  
Adsorption Capacity ◽  
Active Sites ◽  
Batch Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Monolayer Adsorption ◽  
Adsorption Processes ◽  
Pseudo Second Order ◽  
Nanocomposite Adsorbent ◽  
Kinetics Of

Chitosan (CS) and nanocomposite 5%bentonite/chitosan (5%Bt/CS) prepared from the natural biopolymer CS were tested to remove Cu(II) ions using a batch adsorption experiment at various temperatures (25, 35 and 45°C). X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis/differential thermal analysis (TGA/DTA) were used in CS and the nanocomposite characterisation. This confirmed the exfoliation of bentonite (Bt) to form the nanocomposite. The adsorption kinetics of copper on both solids was found to follow a pseudo-second-order law at each studied temperature. The Cu(II) adsorption capacity increased as the temperature increased from 25 to 45°C for nanocomposite adsorbent but slightly increased for CS. The data were confronted to the nonlinear Langmuir, Freundlich and Redlich–Peterson models. It was found that the experimental data fitted very well the Langmuir isotherm over the whole temperature and concentration ranges. The maximum monolayer adsorption capacity for the Cu(II) was 404–422 mg/g for CS and 282–337 mg/g for 5%Bt/CS at 25–45°C. The thermodynamic study showed that the adsorption process was spontaneous and endothermic. The complexation of Cu(II) with NH2 and C = O groups as active sites was found to be the main mechanism in the adsorption processes.

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