scholarly journals Adsorptions of Astrazon Dye onto Granular Carbon-Silica Aerogels Synthesized from Recycle Palm-Date Pits: Kinetics, Thermodynamic and Isotherm Studies

2017 ◽  
Vol 12 (10) ◽  
pp. 4424-4439
Author(s):  
Prof Dr. Ahmed Zaky Sayed

In this work, an environmental friendly management process was achieved to solve solid and liquid hazardous contaminants in our environment. In this case, a granular carbon (gAC) sorbent impregnated with SiO2 aerogels as composite (gAC/SiO2) was synthesized from the rceycling of palm-date pits solid waste products to remediate wastewater solution contaminated with Astrazon pink FG cationic dye. The Astrazon dye adsorption onto the gAC/SiO2 was investigated by compared to gAC sorbent alone using a batch system with respect to initial dye concentration, pH, contact time, solution temperature and adsorbents dosage. It was found the amount of adsorbed dye was strongly depended on pH with low significant important of temperatures levels range from 298 to 318 K. The prepared gAC/SiO2 aerogels composite exhibits high efficiency for Astrazon dye adsorption by approximately 1.5 times than that of gAC alone. The equilibrium adsorption states could be achieved in 6 h when using gAC/SiO2 comparable to 12 h by gAC for the different initial dye concentrations. The adsorption kinetics were  found to best described by the pseudo-second order model (PSOM) and pseudo-first order (PFOM)  kinetic models respectively, when using gAC and gAC/SiO2 sorbents, and poorest-fit with Elvoich equation as confirmed by nonlinear chi-square error test and determination coefficient values. The equilibrium isotherm study indicated that dye adsorption data were analyzed and fitted well by the nonlinear expressions of both Langmuir and Langmuir-Freundlich models compared to Freundlich, Temkin and Redlich–Petersonmodels. The maximum monolayer Astrazon dye adsorption was estimated to be 185.59 and 256.02 µmol/g by gAC and gAC/SiO2 adsorbents. The positive values of the enthalpy (ΔH°) and negative Gibbs free energy (ΔG°) changes indicate an endothermic as well as feasible and spontaneous nature of the adsorption process respectively.

2016 ◽  
Vol 73 (9) ◽  
pp. 2132-2142 ◽  
Author(s):  
F. Ferrarini ◽  
L. R. Bonetto ◽  
Janaina S. Crespo ◽  
M. Giovanela

Adsorption has been considered as one of the most effective methods to remove dyes from aqueous solutions due to its ease of operation, high efficiency and wide adaptability. In view of all these aspects, this study aimed to evaluate the adsorption capacity of a halloysite-magnetite-based composite in the removal of Congo red dye from aqueous solutions. The effects of stirring rate, pH, initial dye concentration and contact time were investigated. The results revealed that the adsorption kinetics followed the pseudo-second-order model, and equilibrium was well represented by the Brunauer–Emmett–Teller isotherm. The thermodynamic data showed that dye adsorption onto the composite was spontaneous and endothermic and occurred by physisorption. Finally, the composite could also be regenerated at least four times by calcination and was shown to be a promising adsorbent for the removal of this dye.


2020 ◽  

<p>One of the known methods for dye removing from waste water is using sorbent material for fine removal of dye .The nano- cation exchanger Sulphonated poly glycidyl methacrylate (SPGMA polymer) was used as sorbent material for removing one of the common cationic dyes. SPGMA polymer was prepared and characterized to ensure its surface ability to sorb dye. Percentage removal of Methylene Blue using SPGMA polymer was studied by changing different parameters as sorbent amount, stirring speed, pH and solution temperature. The maximum value for dye removal was about 98%. Adsorption data from experimental work shows that the results fit the pseudo first order model for all parameters studied except for pH study fits pseudo second order. Also sorption mechanism for SPGMA polymer was studied for different dye concentration.</p>


Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6525
Author(s):  
Guangyuan Yao ◽  
Yuqiang Liu ◽  
Shuilin Zheng ◽  
Ya Xu

Diatomite-based X zeolite was obtained and its crystallinity, morphology, and interface properties were investigated by XRD, BET, SEM, EDS, and XRF. The obtained X zeolite possessed a unique meso-microporous structure and showed good ion exchange properties for Cu2+ and Zn2+. The pseudo-second-order model and Langmuir isotherm model can best describe the adsorption kinetics and isotherms of Cu2+ and Zn2+, respectively. The maximal adsorption capacities of X zeolite for Cu2+ and Zn2+ were 146 and 195 mg/g at 323 K, respectively. Meanwhile, the adsorption process for Cu2+ and Zn2+ were chemical adsorption and ion exchange, respectively. Furthermore, the adsorption data turned out to be an endothermic and spontaneous process. Compared with other reported materials, the adsorption capacity of X zeolite synthesized from diatomite was among the highest. Therefore, it could be a promising adsorbent for the disposal of wastewater that contains metal ions.


Author(s):  
Armin Geroeeyan ◽  
Ali Niazi ◽  
Elaheh Konoz

Abstract In the present research, the removal of Basic Orange 2 (BO2) dye using alkaline-modified clay nanoparticles was studied. To characterize the adsorbent, XRD, FTIR, FESEM, EDX, BET and BJH analyses were performed. The effect of the variables influencing the dye adsorption process such as adsorbent dose, contact time, pH, stirring rate, temperature, and initial dye concentration was investigated. Furthermore, the high efficiency of Ni2+ removal indicated that it is possible to remove both dye and metal cation under the same optimum conditions. The experimental data were analyzed by Langmuir and Freundlich isotherm models. Fitting the experimental data to Langmuir isotherm indicated that the monolayer adsorption of dye occurred at homogeneous sites. Experimental data were also analyzed with pseudo-first-order, pseudo-second-order, and intra-particle diffusion kinetic equations for kinetic modeling of the dye removal process. The adsorption results indicated that the process follows a pseudo-second-order kinetic model. The thermodynamic parameters of the dye adsorption process such as enthalpy, entropy, and Gibbs free energy changes were calculated and revealed that the adsorption process was spontaneous and endothermic in nature. The results presented the high potential of the modified nanoclay as a cost-effective adsorbent for the removal of BO2 dye and Ni2+ from aqueous medium.


Foods ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3127
Author(s):  
Risi Wang ◽  
Ya Li ◽  
Xixiang Shuai ◽  
Jun Chen ◽  
Ruihong Liang ◽  
...  

Traditional aerogels lack specific functional groups for the adsorption of Pb2+, which results in a low adsorption capacity and limits the application scope. Novel porous pectin-based aerogels (PPEAs) were prepared by incorporating polyethylenimine (PEI) using ethylene glycol diglycidyl ether (EGDE) as a cross-linker for the removal of Pb2+ from water. The cross-linking mechanism, morphology, mechanical strength, thermal stability, adsorption properties, and mechanism of the aerogels were investigated. The aerogels possessed several desirable features, such as a large maximum Pb2+ adsorption capacity (373.7 mg/g, tested at pH 5.0), ultralight (as low as 63.4 mg/cm3), high mechanical strength (stress above 0.24 MPa at 50% strain), and easy recyclability. Meanwhile, the equilibrium adsorption data was well described by the Langmuir–Freundlich (Sips) model and the kinetic adsorption process was well fitted using the pseudo-second-order model. The donor groups, such as -NH2, and oxygen-containing functional groups were responsible for the Pb2+ adsorption, which was confirmed by the FTIR and XPS analysis. The excellent characteristics mean that PPEAs are highly effective adsorbents in the remediation of lead-containing wastewater.


2021 ◽  
Vol 34 (1) ◽  
pp. 104-110
Author(s):  
Sonia Rani ◽  
Sudesh Chaudhary

The chickpea husk (Cicer arientum) were activated by chemical modification with sulphuric acid, for its application as biosorbent for the remediation of crystal violet dye from wastewater. Activated chickpea husk (ACH) was characterized for its chemical structure and morphology using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). The after effects of leading affecting parameters like dose of adsorbent, time of contact, pH and concentration were studied by commencing experiments in batch mode. Adsorption mechanism and sorption efficiency of ACH was examined using variety of isotherms (Langmuir & Freundlich) and kinetic models (pseudo first order and pseudo second order). Experimental data for adsorption rate was in good harmony with the results obtained using pseudo second order model. The adsorption capacity determined using Langmuir isotherm and pseudo second order model was found to be 142.85 mg/g.


Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 178
Author(s):  
Serap Sezen ◽  
Vijay Kumar Thakur ◽  
Mehmet Murat Ozmen

Currently, macroporous hydrogels have been receiving attention in wastewater treatment due to their unique structures. As a natural polymer, alginate is used to remove cationic dyes due to its sustainable features such as abundance, low cost, processability, and being environmentally friendly. Herein, alginate/montmorillonite composite macroporous hydrogels (cryogels) with high porosity, mechanical elasticity, and high adsorption yield for methylene blue (MB) were generated by the one-step cryogelation technique. These cryogels were synthesized by adding montmorillonite into gel precursor, followed by chemical cross-linking employing carbodiimide chemistry in a frozen state. The as-prepared adsorbents were analyzed by FT-IR, SEM, gel fraction, swelling, uniaxial compression, and MB adsorption tests. The results indicated that alginate/montmorillonite cryogels exhibited high gelation yield (up to 80%), colossal water uptake capacity, elasticity, and effective dye adsorption capacity (93.7%). Maximum adsorption capacity against MB was 559.94 mg g−1 by linear regression of Langmuir model onto experimental data. The Pseudo-Second-Order model was fitted better onto kinetic data compared to the Pseudo-First-Order model. Improved porosity and mechanical elasticity yielding enhanced dye removal capacity make them highly potential alternative adsorbents compared to available alginate/montmorillonite materials for MB removal.


2013 ◽  
Vol 690-693 ◽  
pp. 1033-1036 ◽  
Author(s):  
Xiao Liu ◽  
Mei Yang ◽  
Yong Yang

Slag haydite made from steel slag and clay was used for phosphate adsorption, and adsorption characteristic was studied. Results showed that the uptake of phosphate was facilitated for pH 3-8, the adsorption process fitted with pseudo-second-order model and intra-particle diffusion model, and the equilibrium time was about 3h. Isotherm adsorption data on slag haydite were fitted by both the Freundlich and Langmuir models. It was found that the data follows the Langmuir model better, and the maximum adsorption capacity increased from 1.17mg·g-1 to 2.42mg·g-1 as temperature rose from 20°C to 40°C. Thermodynamic parameters G0, H0 andS0 showed that the adsorption was spontaneous, endothermic and entropy increase process and increasing temperature was favorable.


2016 ◽  
Vol 42 (2) ◽  
pp. 3-11 ◽  
Author(s):  
Gabriela Ciobanu ◽  
Simona Barna ◽  
Maria Harja

AbstractIn the present study the adsorption of Reactive Blue 19 dye on the hydroxyapatite (HAp) nanopowders was investigated. The batch adsorption experiments were performed by monitoring the adsorbent dosage, contact time, dye solution concentration, pH and temperature. At pH 3 and 20°C, high dye removal rates of about 95.58% and 86.95% for the uncalcined and calcined nanohydroxyapatites, respectively, were obtained. The kinetic studies indicated the dye adsorption onto nanohydroxyapatite samples to follow a pseudo-second order model. The Langmuir isotherm was found to be the best to represent the equilibrium with experimental data. The maximum adsorption capacity of uncalcined and calcined nanohydroxyapatite samples has been found to be 90.09 mg/g and 74.97 mg/g, respectively.


2017 ◽  
Vol 753 ◽  
pp. 243-248 ◽  
Author(s):  
Noorul Farhana Md Ariff ◽  
Megat Ahmad Kamal Megat Hanafiah ◽  
Wan Saime Wan Ngah

In this study, cross-linked chitosan coated bentonite (CCB) beads were prepared as a potential adsorbent to adsorb Cu(II) from aqueous solution. As adsorption capacity was affected by several conditions such as initial Cu(II) concentrations, stirring period and temperature, these parameters were important to be investigated. Three different concentrations of Cu(II) were used in the kinetic study, which were 10, 25 and 50 mg/L. The experimental data was found fitted well with the pseudo-second-order model, an indication that chemisorption was the rate controlling mechanism. Isotherm study was done at different temperatures with concentration of Cu(II) was varied from 10 to 200 mg/L. The maximum monolayer adsorption of Cu(II) on CCB beads based on Langmuir isotherm model at 300, 310 and 320 K were 114.94, 119.05 and 77.52 mg/g, respectively. Therefore, adsorption of Cu(II) was preferred at lower temperatures. This work proved CCB beads as an effective adsorbent for fast removal of Cu(II) from wastewater solutions.


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