scholarly journals Research on Cadmium Adsorption-Desorption Dynamics of Biochars

2021 ◽  
Author(s):  
Zhenyu Zhang ◽  
Shu Dang ◽  
Guiping Zheng ◽  
Haibo Li
Keyword(s):  
Aqueous Solution ◽  
Adsorption Capacity ◽  
Pyrolysis Temperature ◽  
Particle Diffusion ◽  
Aqueous Environment ◽  
Order Model ◽  
Film Diffusion ◽  
Diffusion Stage ◽  
Intra Particle Diffusion ◽  
Adsorption Desorption

Biochar has high potential usage in retaining various contaminants, wastewater treatment, and water purification. In this study, three rice husk derived biochars with pyrolysis temperature 300, 400 and 500 ºC, respectively, and pristine rice rusk were used to remove cadmium from aqueous solution. The results showed that about 70% or more of Cd2+ adsorption occurred in the first 960 mins of adsorption kinetics. The Cd2+ adsorption capacity under equilibrium increased with increasing pyrolysis temperature, probably attributed to the increased specific surface area (SSA) under higher pyrolysis temperature noting that significant linear correlation occurred between Cd2+ adsorption capacity and SSA. The Cd2+ adsorption could be best fitted by pseudo-second order model relative to Elovich model and pseudo-first order model. The Cd2+ adsorption rates were higher in film diffusion stage, indicating that film diffusion stage was significant and fast in the early stage of Cd2+ adsorption. In contrast, Cd2+ adsorption by intra-particle diffusion accounted for 47.0%, 47.9% and 43.9% on average of the total Cd2+ adsorption, respectively, indicating that intra-particle diffusion of Cd2+ played a more predominant role in limiting Cd2+ adsorption rate. When reaching Cd2+ desorption equilibrium, removal ratio (RR) values were averaged 0.96, 0.91, and 0.90 under three initial concentrations. More than 90 percentage on average of Cd2+ was removed from aqueous solution by biochars and rice rusk as well, thus biochars can be used to efficiently remove contaminants from aqueous environment. Cation exchange, electrostatic attraction, and the complexation with surface functional groups could be the main dominant mechanisms for Cd2+ adsorption-desorption on biochars.

scholarly journals Rice Straw Biochar and Magnetic Rice Straw Biochar for Safranin O Adsorption from Aqueous Solution

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 186
Author(s):  
Do Thi My Phuong ◽  
Nguyen Xuan Loc
Keyword(s):  
Aqueous Solution ◽  
Adsorption Capacity ◽  
Rice Straw ◽  
Batch Adsorption ◽  
Particle Diffusion ◽  
Order Kinetic ◽  
Magnetic Biochar ◽  
Intra Particle Diffusion ◽  
Rice Straw Biochar ◽  
Safranin O

This study investigates the adsorption of Safranin O (SO) from aqueous solution by both biochar and magnetic biochar derived from rice straw. Rice straw biochar (RSB) was made by pyrolysis in a furnace at 500 °C, using a heating rate of 10 °C·min−1 for 2 h in an oxygen-limited environment, whilst the magnetic rice straw biochar (MRSB) was produced via the chemical precipitation of Fe2+ and Fe3+. The physicochemical properties of the synthesized biochars were characterized using SEM, SEM- EDX, XRD, FTIR techniques, and N2 adsorption (77 K) and pHpzc measurements. Batch adsorption experiments were used to explore the effect of pH, biochar dosage, kinetics, and isotherms on the adsorption of SO. Experimental data of RSB and MRSB fit well into both Langmuir and Freundlich isotherm models, and were also well-explained by the Lagergren pseudo-second-order kinetic model. The maximum SO adsorption capacity of MRSB was found to be 41.59 mg/g, while for RSB the figure was 31.06 mg/g. The intra-particle diffusion model indicated that the intra-particle diffusion may not be the only rate-limiting step. The collective physical and chemical forces account for the adsorption mechanism of SO molecules by both RSB and MRSB adsorbents. The obtained results demonstrated that the magnetic biochar can partially enhance the SO adsorption capacity of its precursor biochar and also be easily separated from the solution by using an external magnet.

scholarly journals Effective adsorption of nitroaromatics at the low concentration by a newly synthesized hypercrosslinked resin

2017 ◽  
Vol 76 (9) ◽  
pp. 2328-2336 ◽  
Author(s):  
Chuanhong Wang ◽  
Chao Xu ◽  
Weizhi Sun ◽  
Fusheng Liu ◽  
Shitao Yu ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Diffusion Model ◽  
Fixed Bed ◽  
Mesoporous Structure ◽  
Bet Surface Area ◽  
Particle Diffusion ◽  
Adsorption Thermodynamics ◽  
Film Diffusion ◽  
Low Concentrations ◽  
Intra Particle Diffusion

Abstract In the present study, a series of hypercrosslinked resins (CH series) was prepared in systematically designed conditions for the adsorption of nitroaromatics from aqueous solution. The newly synthesized CH-10 possesses a Brunauer–Emmett–Teller (BET) surface area up to 1,329.3 m2/g which is larger than that of the widely used hypercrosslinked resin H-103 and it exhibits great advantage over H-103 when subjected to nitrobenzene at low concentrations. The adsorption capacity of CH-10 for nitrobenzene is 1.4 times as much as that of H-103 at the concentration of 100 mg/L. Kinetic study by film diffusion model and intra-particle diffusion model revealed that its distinctive mesoporous structure within pore diameters between 2 and 6 nm played significant role in the mass transfer at low concentrations, and these unique mesopores also resulted in better adsorption capacity, which was confirmed by adsorption thermodynamics study. Moreover, the CH series displayed a good affinity to a wide scope of nitroaromatics and exhibited excellent dynamic adsorption and desorption properties in fixed bed.

Removal of Hydrophobic Organic Contaminants (HOCs) from Aqueous Solution by Biomimetic Fat Cell (BFC) - The Behavior of Lindane

2013 ◽  
Vol 774-776 ◽  
pp. 609-613
Author(s):  
Li Yan Song ◽  
Ya Jie Yin ◽  
Dou Li
Keyword(s):  
Aqueous Solution ◽  
Organic Contaminants ◽  
Interfacial Polymerization ◽  
Removal Rate ◽  
Correlation Coefficients ◽  
Particle Diffusion ◽  
Fat Cell ◽  
Hydrophobic Organic Contaminants ◽  
Film Diffusion ◽  
Intra Particle Diffusion

Based on the bioaccumulation characteristics of fat cell, an innovative agent, biomimetic fat cell (BFC) has been prepared by interfacial polymerization to remove residual hydrophobic organic contaminants (HOCs) from aqueous solution. BFC exhibited efficient lindane removal from aqueous solution, and 95 % lindane was removed by 20 mg/L BFC at 4.6, 9.3, 19.2, 27.6 and 38.2 μg/L initial concentrations. Removal rate experiments indicated that external film diffusion and intra-particle diffusion accounted for removal rate controlling together. Removal equilibrium fit Freudlich model well with high correlation coefficients. The thermodynamic parameters demonstrated that the removal was favored at low temperature and exothermic in nature.

Removal of Cd(II) from Water System Using Novel Biosorbent Derived from Persimmon Fallen Leaves

2015 ◽  
Vol 1130 ◽  
pp. 685-688
Author(s):  
Rui Yi Fan ◽  
Qing Ping Yi ◽  
Qing Lin Zhang ◽  
Zheng Rong Luo
Keyword(s):  
Aqueous Solution ◽  
Metal Ions ◽  
Adsorption Capacity ◽  
Water System ◽  
Raw Material ◽  
Batch Adsorption ◽  
Diospyros Kaki ◽  
Cadmium Metal ◽  
Fallen Leaves ◽  
Adsorption Desorption

A biosorbent was prepared by treating the persimmon (Diospyros kaki Thunb.) fallen leaves with sodium hydroxide (NaOH). The NaOH concentration and stirring period for the preparation of the biosorbent were adjusted to optimise the Cd(I) adsorption capacity of the biosorbents. Removal of highly toxic Cadmium metal ions from water system using the optimal biosorbent named ‘NPFL’ was investigated using a mimic industrial column. The result showed that NPFL could remove Cd(II) in large quantities from aqueous solution with coexisting metal ions. The raw material, NPFL and Cd(II) loaded NPFL were characterized by SEM-EDS. The reusability of NPFL was also studied by batch adsorption-desorption test.

scholarly journals Recovery of phosphate from aqueous solution by magnetically recycled modified polishing powder composites

2019 ◽  
Vol 80 (7) ◽  
pp. 1357-1366
Author(s):  
Jianming Liu ◽  
Runying Bai ◽  
Junfeng Hao ◽  
Bowen Song ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Ligand Exchange ◽  
Adsorption Process ◽  
High Adsorption ◽  
Order Model ◽  
Powder Composites ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Ph Level ◽  
Adsorption Desorption

Abstract This study investigated a magnetically recycled modified polishing powder (CMIO@PP) as an adsorbent of phosphate; the CMIO@PP was synthesized by combining the modified La/Ce-containing waste polishing powder with CaO2-modified Fe3O4 (CMIO). Results indicate that the CMIO@PP nanocomposite presents a crystal structure comprising La (OH)3, Ce (OH)3, and Fe3O4, and that CMIO is uniformly dispersed in the modified polishing powder. The CMIO@PP (1:3) is a suitable choice considering its magnetism and adsorption capacity. The magnetic adsorbent exhibits a high adsorption capacity of 53.72 mg/g, a short equilibrium time of 60 min, and superior selectivity for phosphate. Moreover, the adsorbent strongly depends on the pH during the adsorption process and maintains a large adsorption capacity when the pH level is between 2 and 6. The adsorption of phosphate by the CMIO@PP (1:3) accords with the Langmuir isotherm model, and the adsorption process follows the pseudo-second order model. Meanwhile, adsorption–desorption experiments show that the adsorbent could be recycled a few times and that a high removal efficiency of phosphate from civil wastewater was achieved. Finally, mechanisms show that the adsorption of phosphate by the CMIO@PP (1:3) is mainly caused by electrostatic attraction and ligand exchange.

scholarly journals Detoxification of Wastewater by Paw–Paw (Carica papaya L.) Seeds Adsorbents

2019 ◽  
Vol 31 (10) ◽  
pp. 2249-2256 ◽  
Author(s):  
Ntaote David Shooto ◽  
Eliazer Bobby Naidoo
Keyword(s):  
Metal Ions ◽  
Carica Papaya ◽  
Surface Adsorption ◽  
Particle Diffusion ◽  
Batch Method ◽  
Order Model ◽  
Significant Drop ◽  
System Parameters ◽  
First Order ◽  
Intra Particle Diffusion

The present work reports the biosorption studies of metal ions viz., Pb(II) and Cu(II) from aqueous solution onto paw-paw seeds (PPS), acid treated paw-paw seeds (ATPPS) and base treated paw-paw seeds (BTPPS) adsorbents by batch method. A series of tests were carried to evaluate the effect of the system parameters, i.e. adsorbent dosage, initial concentration, temperature and contact time. The obtained kinetic data showed that the pseudo first order model best fitted the biosorption of both metal ions with (r2) values of 0.9918, 0.9674 and 0.9463 for Cu(II) onto PPS, ATPPS and BTPPS, respectively and for Pb(II) 0.8513, 0.8686 and 0.9434 onto PPS, ATPPS and BTPPS respectively. Estimated surface adsorption of intra-particle diffusion estimated that surface sorption dominated. Thermodynamic parameter (ΔGo) gave negative values indicating that the biosoption processes were spontaneous and feasible. ΔHo gave positive and negative values indicating that some biosorption processes were endothermic and some exothermic. Isotherm data indicated that Langmuir best described the biosorption. The reusability of PPS, ATPPS and BTPPS adsorbents was evaluated up to five cycles without showing significant drop in sorption efficiency.

Adsorption of Alizarin Red from Aqueous Solution Using Ultra-Fine Fly Ash

2012 ◽  
Vol 518-523 ◽  
pp. 2307-2314 ◽  
Author(s):  
Bei Gang Li ◽  
Li Yuan Zhao
Keyword(s):  
Aqueous Solution ◽  
Fly Ash ◽  
Rate Equation ◽  
Removal Rate ◽  
Physical Adsorption ◽  
Particle Diffusion ◽  
Alizarin Red ◽  
Order Rate ◽  
Intra Particle Diffusion ◽  
Order Rate Equation

Alizarin Red (AR) has been shown to be effectively removed from aqueous solution using the ultrafine fly ash (UFA) prepared by ball milling from raw fly ash (FA), a low-cost industrial solid waste. The maximum removal rate was 91.04% in a solution of initial AR concentration of 700 mg/L, adsorption time of 60 min at pH 5.0 and temperature of 25°C. Compared with FA, the adsorption capacity of UFA is higher for AR removal. Effects of important parameters, contact time, adsorbate concentration, pH and temperature, were investigated. The UFA and AR-loaded UFA were characterized by FT-IR. The equilibrium, kinetics and thermodynamics of AR adsorption onto UFA were evaluated. The AR uptake process followed the pseudo-second-order rate equation well, but the pseudo-first-order rate equation and intra-particle diffusion equation could only be applied to describe the initial stage of adsorption, furthermore, intra-particle diffusion might be the rate-controlling step of fast adsorption process. The sorption decreased with increasing temperature and the adsorption apparent activation energy was 8.28kJ/mol. Langmuir isotherm equation could better describe the adsorption equilibrium at different temperatures, compared with Freundlich model. Thermodynamic parameters, ΔG, ΔH and ΔS, were also calculated. The results inferred that the adsorption of AR/UFA system was feasible, spontaneous and exothermic nature of the process which was mainly controlled by physical adsorption.

scholarly journals FLY ASH MAGNETIC ADSORBENT FOR CADMIUM ION REMOVAL FROM AN AQUEOUS SOLUTION

2021 ◽  
Vol 185 (1) ◽  
pp. 42-50
Author(s):  
Gabriela BUEMA ◽  
Nicoleta LUPU ◽  
Horia CHIRIAC ◽  
Dumitru Daniel HEREA ◽  
Lidia FAVIER ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Fly Ash ◽  
Adsorption Capacity ◽  
Second Order ◽  
Order Model ◽  
Cadmium Ion ◽  
Cadmium Ions ◽  
Ion Removal ◽  
Pseudo Second Order ◽  
Second Order Model

The fly ash generated from a Romanian power plant was used as a starting material in this study. The aim of the study was to obtain a low cost material based on the treatment of fly ash with Fe3O4 for utilization as an adsorbent for cadmium ion removal. The adsorbent that was synthesized was characterized using different techniques. The adsorption process was investigated by the batch technique at room temperature. The quantity of cadmium ion adsorbed was measured spectrophotometrically. The experimental data showed that the material can remove cadmium ions at all three working concentrations. The adsorption capacity increased with an increase in concentration, respectively contact time. The results were analyzed through two kinetic models: pseudo first order and pseudo second order. The kinetics results of cadmium adsorption onto a magnetic material are in good agreement with a pseudo second order model, with a maximum adsorption capacity of 4.03 mg/g, 6.73 mg/g, and 9.65 mg/g. Additionally, the pseudo second order model was linearized into its four types. The results indicated that the material obtained show the ability to remove cadmium ions from an aqueous solution.

Adsorption of 2,4-Dichlorophenoxyacetic Acid from Aqueous Solution Using Carbonized Chest Nut as Low Cost Adsorbent: Kinetic and Thermodynamic

2020 ◽  
Vol 234 (3) ◽  
pp. 461-484
Author(s):  
Jale Gülen ◽  
Sabri Aslan
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Low Cost ◽  
Isotherm Models ◽  
Particle Diffusion ◽  
Dichlorophenoxyacetic Acid ◽  
Adsorption Dynamics ◽  
Intra Particle Diffusion ◽  
Different Temperatures ◽  
2,4 Dichlorophenoxyacetic Acid

AbstractThe activated carbon was made of carbonized chest nut shell (CCS) and used as low cost adsorbent for 2,4-D (2,4-dichlorophenoxyacetic acid) removal. The experiments were conducted at different temperatures such as 35, 45 and 55 °C and this system represents as L type adsorption behavior. The experimental data were modelled using several isotherm models such as Langmuir, Freundlich, Temkin and Dubinin Radushkevich. The adsorption dynamics were searched by applying pseudo first, pseudo second and intra particle diffusion models. The thermodynamic approach was conducted for determining the thermodynamic values of ΔH°, ΔS° and ΔG°.

Pyridinium-functionalized magnetic mesoporous silica nanoparticles as a reusable adsorbent for phosphate removal from aqueous solution

2016 ◽  
Vol 74 (5) ◽  
pp. 1127-1135 ◽  
Author(s):  
Fang Ma ◽  
Hongtao Du ◽  
Ronghua Li ◽  
Zengqiang Zhang
Keyword(s):  
Aqueous Solution ◽  
Silica Nanoparticles ◽  
Adsorption Capacity ◽  
Mesoporous Silica Nanoparticles ◽  
Phosphate Removal ◽  
Maximum Adsorption Capacity ◽  
Intra Particle Diffusion ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Magnetic Mesoporous Silica

In this work, pyridinium-functionalized silica nanoparticles adsorbent (PC/SiO2/Fe3O4) was synthesized for phosphate removal from aqueous solutions. The removal efficiency of phosphate on the PC/SiO2/Fe3O4 was carried out and investigated under various conditions such as pH, contact temperature and initial concentration. The results showed that the adsorption equilibrium could be reached within 10 min, which fitted a Langmuir isotherm model, with maximum adsorption capacity of 94.16 mg/g, and the kinetic data were fitted well by pseudo-second-order and intra-particle diffusion models. Phosphate loaded on the adsorbents could be easily desorbed with 0.2 mol/L of NaOH, and the adsorbents showed good reusability. The adsorption capacity was still around 50 mg/g after 10 times of reuse. All the results demonstrated that this pyridinium-functionalized mesoporous material could be used for the phosphate removal from aqueous solution and it was easy to collect due to its magnetic properties.

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