scholarly journals Enhancement of the Congo Red Adsorption Capacity of Biochars by Surface Modification with MgCl2 Pretreatment

2020 ◽  
Vol 42 (10) ◽  
pp. 472-481
Author(s):  
Hee So Oh ◽  
Jae-Soo Chang
Keyword(s):  
Surface Modification ◽  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Congo Red ◽  
Raw Materials ◽  
Physicochemical Characteristics ◽  
Pine Sawdust ◽  
Adsorption Capacities ◽  
Initial Ph ◽  
Surface Modified

Objectives : The physicochemical characteristics of Mg-biochar composites derived from kelp and pine after pretreatment with MgCl2 were analyzed, and their adsorption capacities for an anionic dye, Congo red (CR), were evaluated.Methods : After pretreating 60 g of kelp and pine sawdust in 1 L of 0.1 M MgCl2･6H2O, the raw materials were pyrolyzed at 500℃ to produce Mg-biochar composites (kelp based KB-Mg and pine based PB-Mg). The fundamental physicochemical characteristics of the Mg-biochar composites were examined, and their adsorption capacities for CR were investigated using different initial pH values, adsorption kinetic models, and adsorption isotherm models.Results and discussion : The Mg-biochar composites showed the development of uniform deposits of Mg minerals primarily as MgO crystal on the surface by the surface modification with MgCl2. When the pristine biochars were surface-modified with MgCl2, their adsorption capacities for CR were significantly increased over the entire pH range tested. The CR adsorption process by all biochars was best described with the pseudo-first order kinetics model, and the adsorption isotherm characteristics were better described with the Langmuir isotherm model for all biochars. The Langmuir maximum adsorption capacities for KB-Mg and PB-Mg were 423.0 mg/g and 394.7 mg/g, respectively. It is suggested that the main mechanism for CR adsorption on the Mg-biochars is electrostatic attraction between CR and the biochars.Conclusions : The results showed that surface modification with MgCl2 could greatly enhance the CR adsorption capacity of biochars, and the results demonstrated the great potential of KB-Mg and PB-Mg for CR removal.

Adsorption of cadmium(II) from aqueous solution onto activated carbon

1997 ◽  
Vol 35 (7) ◽  
pp. 205-211 ◽  
Author(s):  
R. Leyva-Ramos ◽  
J. R. Rangel-Mendez ◽  
J. Mendoza-Barron ◽  
L. Fuentes-Rubio ◽  
R. M. Guerrero-Coronado
Keyword(s):  
Activated Carbon ◽  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Freundlich Isotherm ◽  
Carbon Surface ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Ph Values ◽  
Average Percent Deviation ◽  
Initial Ph

The adsorption isotherm of cadmium on activated carbon was measured in a batch adsorber. Effects of temperature and solution pH on the adsorption isotherm were investigated by determining the adsorption isotherm at temperatures of 10, 25, and 40°C and at initial pH values from 2 to 8. Langmuir isotherm better fitted the experimental data since the average percent deviation was lower than with the Freundlich isotherm It was noticed that the amount of Cd2+ adsorbed was reduced about 3 times by increasing the temperature from 10 to 40°C. It was found that Cd2+ was not adsorbed on activated carbon at pH of 2 or lower and that Cd2+ was precipitated out as Cd(OH)2 at pH values above 9. Maximum adsorption capacity was observed at pH of 8 and the adsorption capacity was decreased about 12 times by reducing the initial pH from 8 to 3. According to the cadmium speciation diagram the predominant species below pH of 8 is Cd2+. Thus, cadmium was adsorbed on the activated carbon surface as Cd2+. It was concluded that the adsorption capacity is a strong function of pH and temperature.

Synthesis of Magnetite Nano-Particles and Powder Activated Carbon as a Novel Material for Water Treatment

2009 ◽  
Vol 620-622 ◽  
pp. 145-148
Author(s):  
Gyu Tae Seo ◽  
Jin Tae Kim ◽  
Sung Su Kim ◽  
Jutamas Kaewsuk
Keyword(s):  
Surface Modification ◽  
Activated Carbon ◽  
Water Treatment ◽  
Adsorption Capacity ◽  
Surface Characteristics ◽  
Nano Particles ◽  
Specific Selectivity ◽  
Novel Material ◽  
Powder Activated Carbon ◽  
Surface Modified

The objective of this study is to develop a novel powder activated carbon (PAC) by surface modification with magnetite nano-particles for enhanced removal of NOM in water. The PAC used for experiment was two types, SAC (wood-based) and MAC (coal-based). First the PAC was treated by heat at 650 or 900 °C for 1hr under N2. And then the PAC surface was synthesized with magnetite nano-particles at the same condition. Adsorption tests of NOM were carried out to identify functional characteristics of the surface modified. Despite reduced surface area, adsorption capacity of the surface modified PAC was comparable to the virgin one. However much increased adsorption capacity was obtained by heat treatment of the PACs. SEC and SUVA254 results showed no specific selectivity in removal of NOM by the modification of PAC surface characteristics. Enhanced oxidation of the NOM was also observed by the magnetite nano-particle synthetic PACs in contact with ozone. Conclusively the surface modification of the PAC has high potential as a novel adsorption material for advanced water treatment.

scholarly journals The Effect of SBA-15 Surface Modification on the Process of 18β-Glycyrrhetinic Acid Adsorption: Modeling of Experimental Adsorption Isotherm Data

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3671 ◽  
Author(s):  
Michał Moritz ◽  
Małgorzata Geszke-Moritz
Keyword(s):  
Surface Modification ◽  
Adsorption Capacity ◽  
Raw Materials ◽  
Porous Silica ◽  
Bioactive Compound ◽  
Glycyrrhetinic Acid ◽  
Plant Materials ◽  
Nonlinear Fitting ◽  
Pentacyclic Triterpenoid ◽  
Vegetable Raw Materials

This study aimed at the adsorption of 18β-glycyrrhetinic acid (18β-GA), a pentacyclic triterpenoid derivative of oleanane type, onto functionalized mesoporous SBA-15 silica and non-porous silica (Aerosil®) as the reference adsorbent. Although 18β-GA possesses various beneficial pharmacological properties including antitumor, anti-inflammatory, and antioxidant activity, it occurs is small amounts in plant materials. Thus, the efficient methods of this bioactive compound enrichment from vegetable raw materials are currently studied. Siliceous adsorbents were functionalized while using various alkoxysilane derivatives, such as (3-aminopropyl)trimethoxysilane (APTMS), [3-(methylamino)propyl]trimethoxysilane (MAPTMS), (N,N-dimethylaminopropyl)trimethoxysilane (DMAPTMS), and [3-(2-aminothylamino)propyl] trimethoxysilane (AEAPTMS). The effect of silica surface modification with agents differing in the structure and the order of amine groups on the adsorption capacity of the adsorbent and adsorption efficiency were thoroughly examined. The equilibrium adsorption data were analyzed while using the Langmuir, Freundlich, Redlich-Peterson, Temkin, Dubinin-Radushkevich, and Dubinin-Astakhov isotherms. Both linear regression and nonlinear fitting analysis were employed in order to find the best-fitted model. The adsorption isotherms of 18β-GA onto silicas functionalized with APTMS, MAPTMS, and AEAPTMS indicate the Langmuir-type adsorption, whereas sorbents modified with DMAPTMS show the constant distribution of the adsorbate between the adsorbent and the solution regardless of silica type. The Dubinin-Astakhov, Dubinin-Radushkevich, and Redlich-Peterson equations described the best the process of 18β-GA adsorption onto SBA-15 and Aerosil® silicas that were functionalized with APTMS, MAPTMS, and AEAPTMS, regardless of the method that was used for the estimation of isotherm parameters. Based on nonlinear fitting analysis (Dubinin-Astakhov model), it can be concluded that SBA-15 sorbent that was modified with APTMS, MAPTMS, and AEAPTMS is characterized by twice the adsorption capacity (202.8–237.3 mg/g) as compared to functionalized non-porous silica (118.2–144.2 mg/g).

Preparation and Chelating Properties of Polystyrene Modified Ethoxycarbonyl Thiourea Resin

2011 ◽  
Vol 239-242 ◽  
pp. 781-785 ◽  
Author(s):  
Shuai Wang ◽  
Hong Zhong ◽  
Liu Yin Xia ◽  
Zhong Nan Wang ◽  
Qian Zhang
Keyword(s):  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Maximum Adsorption Capacity ◽  
Polymer Grafting ◽  
Isotherm Equation ◽  
Adsorption Capacities ◽  
Adsorption Data ◽  
Separation Factors ◽  
Langmuir Isotherm Equation ◽  
Freundlich Adsorption Isotherm

A novel polystyrene modified ethoxycarbonyl thiourea resin(PSETU) was synthesized by polymer grafting of aminated polystyrene and ethoxycarbonyl isothiocyanate. The adsorption capacities of PSETU follow the order: Au(III) > Cu(II) > Zn(II) > Ni(II) > Fe(III) > Ca(II) ≈ Mg(II). The adsorption capacity for Au(III) increases with the increase of contact time, temperature and initial concentration of Au(III). The adsorption data fit Boyd’s diffusion equation of liquid film, Langmuir adsorption isotherm and Freundlich adsorption isotherm. The maximum adsorption capacity of PSETU calculated by Langmuir isotherm equation is 3.485 mmol/g, and the separation factors of PSETU for Au(III)-base metal ions are above 380. According to XPS results, the functional atoms of PSETU coordinate with Au(III) during the adsorption process.

scholarly journals Comparison of Cation Anion Dye Removal Characteristics between Kelp-based Magnetic Biochar and Pine-based Magnetic Biochar

2020 ◽  
Vol 42 (6) ◽  
pp. 308-318 ◽  
Author(s):  
Hee So Oh ◽  
Jae-Soo Chang
Keyword(s):  
Adsorption Capacity ◽  
Iron Oxides ◽  
Second Order ◽  
Kinetics Model ◽  
Isotherm Models ◽  
Adsorptive Capacity ◽  
Magnetic Biochar ◽  
Adsorption Capacities ◽  
Pseudo Second Order ◽  
Surface Modified

Objectives:This study investigates the adsorption capacity of magnetic biochar (KB-Fe) derived from kelp for two dyes, Congo red (CR) and crystal violet (CV), which have different charge characteristics. The adsorption capacities were compared to magnetic biochar (PB-Fe) derived from pine.Methods:Pristine biochars (KB, PB) were produced through the pyrolysis of kelp and pine sawdust at 500℃. Magnetic biochars (KB-Fe, PB-Fe) were produced by treatment of 60 g of biomass in 1 L of 0.1 M FeCl<sub>3</sub>･6H<sub>2</sub>O and pyrolysis of the raw materials at 500℃. The fundamental characteristics of the biochars were analyzed, and the adsorption capacities of the biochars for the CR and CV dyes were evaluated based on two adsorption isotherm models, two adsorption kinetics models, and adsorption characteristics based on changes to the pH between 5 and 11.Results and discussion:CR adsorption by all biochars decreased with an increase in pH. When KB and PB were surface-modified with magnetic iron oxides, their adsorption capacity for CR increased. CV adsorption by all biochars increased with pH. When KB and PB were surface-modified with magnetic iron oxides, their adsorption capacity for CV considerably decreased. According to the Langmuir isotherm model, the adsorption capacity for CR was in the order of KB-Fe, KB, PB-Fe, and PB, and the adsorption capacity for CV was in the order of KB, PB, PB-Fe, and KB-Fe. The CR adsorption was better described by the pseudo-second order kinetics model for all biochars, with the exception of KB-Fe. CV adsorption was also better described by the pseudo-second order kinetics model for all biochars, with the exception of KB.Conclusions:The results show that kelp biochar has great potential for the adsorptive removal of CR and CV compared to pine-based biochar. In addition, it was demonstrated that surface modification of kelp biochar with magnetic iron oxides can significantly improve its adsorptive capacity for anionic dyes; however, its adsorptive capacity for cationic dyes decreases.

A functionalized tannin-chitosan bentonite composite with superior adsorption capacity for Cr(VI)

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Zhongmin Li ◽  
Peng Zou ◽  
Junzhou Yang ◽  
Miaoyang Huang ◽  
Linye Zhang ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Raw Materials ◽  
Low Cost ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
Initial Ph ◽  
System Part ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Xrd Patterns

AbstractA novel functionalized tannin-chitosan bentonite composite (TCBC) was successfully synthesized. The formation of the composite was confirmed by the X-ray diffraction (XRD) patterns and Fourier transform infrared spectroscopy (FT-IR) analysis. The pHpzc of TCBC was 3.38. The influences such as pH, dosage of TCBC, temperature and initial Cr(VI) concentration on adsorption capacity were investigated. The experimental data indicated that the almost saturated adsorption of the TCBC towards Cr(VI) in 100 min. The maximum adsorption capacity was 262.08 mg/g at 333 K with initial pH = 2.5. The adsorption kinetics of Cr(VI) on TCBC followed the pseudo-second-order kinetics model. The isothermal data were well described by the models of Langmuir, Freundlich and Temkin. The results revealed that the adsorption of Cr(VI) on TCBC existed comprehensive effects and mainly belong to the chemisorption. The TCBC could keep good performances (qe = 192.17 mg/g) in five runs, 1 M NaOH was used as eluent for desorption, which showed a high desorption efficiency. Studies showed TCBC prepared with low cost and green raw materials, and simple green preparation technology had high adsorption capacity, good reusability and acidic tolerance. By exploring the Cr(VI)-Cr(III) hybrid system, part of Cr(VI) was reduced to Cr(III) and adsorbed by TCBC. The optimal adsorption pH of Cr(III) was 5.0.

Adsorption Characteristics of Congo Red from Aqueous Solution on the Carboxymethylcellulose/Montmorillonite Nanocomposite

2012 ◽  
Vol 450-451 ◽  
pp. 769-772 ◽  
Author(s):  
Ya Hong Zhao ◽  
Li Wang
Keyword(s):  
Adsorption Capacity ◽  
Adsorption Kinetics ◽  
Congo Red ◽  
Ph Value ◽  
Contact Temperature ◽  
Solution Intercalation ◽  
Adsorption Behaviors ◽  
Initial Ph ◽  
Pseudo Second Order ◽  
Kinetics And Isotherms

The carboxymethylcellulose/montmorillonite (CMC/MMT) nanocomposite was prepared by a solution intercalation technique. The effects of contact temperature, the initial pH value of dye solution, contact time and the initial dye concentration on the adsorption capacitiy of CMC/MMT nanocomposite for Congo red (CR) were investigated. The adsorption kinetics and isotherms of nanocomposite were also studied. The results indicated that with the contact temperature increasing and the initial pH value decreasing, the adsorption capacity of the CMC/MMT nanocomposite increased. Compared with the adsorption capacity of CMC (62.42 mg/g), the nanocomposite exhibited the higher adsorption capacity (161.08 mg/g). The adsorption behaviors of CMC/MMT nanocomposite showed that the adsorption kinetics and isotherms were in good agreement with pseudo-second-order equation and the Langmuir equation.

Adsorption CO2 on Activated Carbon with Surface Modification

2013 ◽  
Vol 634-638 ◽  
pp. 746-750 ◽  
Author(s):  
Cheng Lin ◽  
Hui Yun Zhang ◽  
Xiao Ying Lin ◽  
Yun Fei Feng
Keyword(s):  
Surface Modification ◽  
Activated Carbon ◽  
Activate Carbon ◽  
Adsorption Capacity ◽  
Flue Gas ◽  
Adsorption Process ◽  
Low Cost ◽  
Solid Sorbent ◽  
Adsorption Capacities ◽  
New Type

The success of CO2 capture from flue gas with solid sorbent is dependent of a low cost sorbent with high CO2 adsorption capacity and selectivity. Modifying surface texture of activated carbon with impregnating amines is expected to offer the benefits of liquid amines in the typical adsorption process routes. In this work, cocoanut activate carbon (AC) is firstly alkalified by KOH solution, then modified by impregnation of tetraethylenepentamine (TEPA), triethylenetetramine (TATA), and triethanolamine (TEA) to form a new type of sorbents. The effects of alkalifying treatment and temperature on CO2 adsorption capacities of the sorbents are investigated. Results indicate that the activate carbons modified by combining alkalification pretreatment firstly and then impregnated amines at low temperature are profitable for CO2 adsorption. The adsorption capacities of CO2 are enhanced with TEPA and TETA impregnation on the activate carbon pretreated by KOH solution. And CO2 adsorption capacity of new sorbents is stable after many adsorption and desorption cycles.

Competitive adsorption of organic solvents using modified and unmodified calcium bentonite clay mineral

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Organic Solvents ◽  
Competitive Adsorption ◽  
Correlation Factor ◽  
Isotherm Model ◽  
Isotherm Models ◽  
High Concentration ◽  
Dual Purpose ◽  
Calcium Bentonite

Dodecyltrimethylammonium bromide (DTAB)–modified and unmodified calcium bentonite were both used for the competitive adsorption of aromatics (xylene, ethylbenzene and toluene) and petroleum products (gasoline, dual purpose kerosene and diesel) from their aqueous solution. Infrared spectroscopy (IR) and expansion tests (adsorption capacity and Foster swelling) measurement were performed in order to evaluate the performance of the adsorbents. The Foster swelling index and adsorption capacity of the DTAB modified calcium bentonite in the organic solvents follow the trend: xylene &gt; ethylbenzene &gt; toluene &gt; gasoline &gt; dual purpose kerosene (DPK) &gt; diesel &gt; water. However, the adsorption capacity of the adsorbent in diesel outweighed the adsorption capacity in DPK at high concentration of DTAB indicating that diesel has higher affinity for high DTAB concentration than DPK. The percentage removal of the solvent is directly proportional to the concentration of DTAB used in modifying the bentonite as well as the contact time between the adsorbent and the solvent, hence modified calcium bentonite adsorbed a higher percentage of organic solvents than the unmodified calcium bentonite. The adsorption characteristics of both adsorbents improved remarkably after proper agitation of the organic solvents, the unmodified calcium bentonite however adsorbed more water than the modified bentonite. Data obtained from adsorption isotherm models confirms that Freundlich adsorption isotherm model was favored more than Langmuir adsorption isotherm model with the correlation factor (R2) of the former tending more towards unity. The adsorption of ethylbenzene using DTAB modified and unmodified calcium bentonites follow a pseudo second order kinetics mechanism, suggesting that the rate determining step of adsorption involves both the adsorbent and the organic solvent.

The use of insoluble matter of Moroccan oil shale for removal of dyes from aqueous solution

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Methylene Blue ◽  
Oil Shale ◽  
Heating Temperature ◽  
Blue Dye ◽  
Adsorption Capacities ◽  
Experimental Parameters ◽  
Initial Ph ◽  
New Material ◽  
Activating Agent ◽  
Moderate Cost

The study aims to use an adsorbent natural based of Moroccan oil shale of Timahdit area (Y layer) in a physical-chemical adsorption process for treating industrial discharges colorful. The used adsorbent is the insoluble party of the sub-critical extraction of decarbonized oil shale of Timahdit. The tests performed on the methylene blue (MB), showed a strong elimination in the first 10 minutes. The influences of various experimental parameters were studied: mass ratio of adsorbent, time and temperature of thermal treatment, contact time, pH of MB and heating temperature of solution on the parameters of material were studied. The experimental results have shown that the adsorption of methylene blue dye by the adsorbent is more than 90% at initial pH a range 6-7 at room temperature for 30 minutes. The process is simple and the adsorbent produced is a new material with interesting adsorption capacities of moderate cost which does not require an activating agent and can be used as industrial adsorbent for the decontamination of effluents containing organic pollutants.

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