scholarly journals Hydroxyapatite/Carboxymethyl Cellulose Composite: Synthesis, Characterization, Kinetic, Thermodynamic Study for Removal of Cr (III)

In the present work nano-hydroxyapatite (n-HAp)/Carboxymethyl Cellulose (CMC) composite was synthesized. The n-HApCMC composite was tested for the adsorption of Chromium from aqueous solution and compared its removal capacity with nano-hydroxyapatite (n-HAp). Equilibrium data were fitted well in the Langmuir and Freundlich isotherm models. The thermodynamic analysis also established that the adsorption process was endothermic and spontaneous.

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Neway Belachew ◽  
Hirpo Hinsene

AbstractIn the current work, we have reported a cationic surfactant-modified Ethiopian kaolin for improved adsorption of Cr(VI) from aqueous solution. The raw kaolin was modified by treating with CTAB to enhance the adsorption properties. The crystal structure and vibrational analysis of CTAB–kaolin were investigated by Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction (p-XRD) techniques. The successful modification of kaolin by CTAB through intercalation and coating was investigated by XRD and FTIR. p-XRD confirms the raw kaolin obtained from Belesa, Tigo kebele is kaolinite mineral. The study has also focused on the application of kaolin–CTAB for adsorption of hexavalent chromium. The percent removal of Cr(VI) was investigated at different parameters such as pH, contact time, concentration of Cr(VI) and adsorbent dosage. CTAB–kaolin shows 99% removal of Cr(VI) at the adsorption equilibrium (time = 180 min, 100 mg CTAB–kaolin, 10 ppm/100 ml). The Langmuir and Freundlich isotherm models were used to investigate the adsorption process of chromium onto kaolin–CTAB composites. The equilibrium data obeyed Langmuir model than Freundlich, which shows that the adsorption process proceeds through monolayer adsorption and maximum adsorption capacity was found to be Qo = 22.72 mg/g. The pseudo-second-order kinetics model is found to be well fitted than Pseudo-first-order kinetics, which implies that the adsorption mechanism more favors electrostatic interaction between chromium and kaolin–CTAB composites. In conclusion, CTAB–kaolin was found to be a promising adsorbent for the efficient removal of Cr(VI) from the aqueous solution.


2019 ◽  
Vol 9 (21) ◽  
pp. 4486 ◽  
Author(s):  
Candelaria Tejada-Tovar ◽  
Angel Darío Gonzalez-Delgado ◽  
Angel Villabona-Ortiz

The removal of water pollutants has been widely addressed for the conservation of the environment, and novel materials are being developed as adsorbent to address this issue. In this work, different residual biomasses were employed to prepare biosorbents applied to lead (Pb(II)) ion uptake. The choice of cassava peels (CP), banana peels (BP), yam peels (YP), and oil palm bagasse (OPB) was made due to the availability of such biomasses in the Department of Bolivar (Colombia), derived from agro-industrial activities. The materials were characterized by ultimate and proximate analysis, Fourier Transform Infrared Spectroscopy (FTIR), Brunauer-Emmett-Teller analysis (BET), Scanning Electron Microscopy (SEM), and Energy Dispersive X-Ray Spectroscopy (EDS) in order to determine the physicochemical properties of bioadsorbents. The adsorption tests were carried out in batch mode, keeping the initial metal concentration at 100 ppm, temperature at 30 °C, particle size at 1 mm, and solution pH at 6. The experimental results were adjusted to kinetic and isotherm models to determine the adsorption mechanism. The remaining concentration of Pb(II) in solution was measured by atomic absorption at 217 nm. The functional groups identified in FTIR spectra are characteristic of lignocellulosic materials. A high surface area was found for all biomaterials with the exception of yam peels. A low pore volume and size, related to the mesoporous structure of these materials, make these bioadsorbents a suitable alternative for liquid phase adsorption, since they facilitate the diffusion of Pb(II) ions onto the adsorbent structure. Both FTIR and EDS techniques confirmed ion precipitation onto adsorbent materials after the adsorption process. The adsorption tests reported efficiency values above 80% for YP, BP, and CP, indicating a good uptake of Pb(II) ions from aqueous solution. The results reported that Freundlich isotherm and pseudo-second order best fit experimental data, suggesting that the adsorption process is governed by chemical reactions and multilayer uptake. The future prospective of this work lies in the identification of alternatives to reuse Pb(II)-contaminated biomasses after heavy metal adsorption, such as material immobilization.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
I. Osasona ◽  
O. O. Ajayi ◽  
A. O. Adebayo

The feasibility of using powdered cow hooves (CH) for removing Ni2+ from aqueous solution was investigated through batch studies. The study was conducted to determine the effect of pH, adsorbent dosage, contact time, adsorbent particle size, and temperature on the adsorption capacity of CH. Equilibrium studies were conducted using initial concentration of Ni2+ ranging from 15 to 100 mgL−1 at 208, 308, and 318 K, respectively. The results of our investigation at room temperature indicated that maximum adsorption of Ni2+ occurred at pH 7 and contact time of 20 minutes. The thermodynamics of the adsorption of Ni2+ onto CH showed that the process was spontaneous and endothermic. Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm models were used to quantitatively analysed the equilibrium data. The equilibrium data were best fitted by Freundlich isotherm model, while the adsorption kinetics was well described by pseudo-second-order kinetic equation. The mean adsorption energy obtained from the D-R isotherm revealed that the adsorption process was dominated by physical adsorption. Powdered cow hooves could be utilized as a low-cost adsorbent at room temperature under the conditions of pH 7 and a contact time of 20 minutes for the removal of Ni(II) from aqueous solution.


2015 ◽  
Vol 754-755 ◽  
pp. 950-954
Author(s):  
Mohd Faisal Taha ◽  
Anis Suhaila Shuib ◽  
Maizatul Shima Shaharun ◽  
Azry Borhan

An attempt was made to study the potential of rice husk as an alternative cheap precursor for activated carbon to remove Ni2+ from aqueous solution. Rice husk was treated chemically (with NaOH) and physically (carbonization) to prepare rice husk based activated carbon (RHAC). The textural properties of RHAC, i.e. surface area (255 m2/g) and pore volume (0.17 cm2/g), were determined by N2 adsorption using Brunauer-Emmett-Teller (BET) surface analyzer. RHAC was also characterized for its morphology and its elemental compositions. The adsorption studies for the removal of Ni2+ from aqueous solution were carried out using different dosage of RHAC as adsorbent as a function of varied contact time. The concentration of Ni2+ was determined by atomic absorption spectrometer (AAS). The results obtained from adsorption studies indicate good potential of rice husk as a cheap precursor to produce activated carbon for the removal of Ni2+ from aqueous solution. The equilibrium data from adsorption studies fitted well the of Langmuir and Freundlich isotherm models.


2011 ◽  
Vol 148-149 ◽  
pp. 470-473
Author(s):  
Li Fang Zhang

The biosorption of Malachite Green from aqueous solution was investigated by using pretreated fungal biomass in a batch system. The effects of initial pH, NaCl concentration, initial dye concentration and temperature on dye biosorption were studied. The results showed that the pretreated fungal biomass exhibited higher dye removal at initial pH value of 5.0-6.0. The bosorption capacity was increased with the increasing temperature in studied temperature range. The Langmuir and Freundlich isotherm models were applied to experimental equilibrium data and the Langmuir model better described the equilibrium dye uptake than the Freundlich model. Thermodynamic studies revealed that the biosorption process was successful, spontaneous and endothermic in nature.


2011 ◽  
Vol 695 ◽  
pp. 73-76 ◽  
Author(s):  
An Kai Luo ◽  
Xue Gang Luo ◽  
Xiao Yan Lin

The adsorption of Cd(II) ions from aqueous solution by sodium hydroxide-treated bamboo powder(STB) was studied in a batch adsorption system. Characteristics of STB were investigated by scanning electron microscopy (SEM) and electron dispersive spectroscopy (EDS). Factors influencing adsorption such as pH of the solution, adsorbent dosage, cadmium concentration and temperature have been studied. The adsorption process was relatively fast and equilibrium was achieved after 120 min, and the maximum adsorption of Cd(II) ions occurred at around pH 6.5. The equilibrium data were fitted using Langmuir, Temkin and Freundlich isotherm models to calculate isotherm constants. And the adsorption isotherm fitted well Langmuir isotherm, and the maximum adsorption capacity was 8.987 mg/g.


2018 ◽  
Vol 4 (3) ◽  
pp. 297-302
Author(s):  
S. Jayashree ◽  
Jeyavathana Samuel ◽  
R. Vashantha

The main objective of this study was to investigate the removal of cadmium(II) ions from aqueous solution using raw Cymbopogon citratus as an adsorbent. It was characterized by FT-IR, XRD, SEM-EDAX and its physical parameters were analyzed. Different factors such as pH, contact time, initial concentration and temperature were studied. Maximum adsorption was taken place at the optimum pH of 6 and the equilibrium data were analyzed by Langmuir, Freundlich and Temkin Isotherm models. Among those isotherm models Langmuir and Temkin were fitted well with good correlation coefficient (R2). The negative values of ΔG⁰ for all temperature shows the adsorption process for cadmium(II) ion was spontaneous in nature and feasible. The negative value of enthalpy change ΔH⁰ shows the adsorption process is exothermic and the positive value of ΔS⁰ indicates the disorderness or randomness process of adsorption. The positive value of Ea indicates the higher solution temperature favors the adsorption of metal ion onto RCC. The experimental data were analyzed by kinetic studies such as pseudo-first order, pseudo-second order and intra-particle diffusion models. Desorption was also studied and the recovery of the adsorbent was found to be 10%. Thus on the basis of these investigations the present study concludes that the raw Cymbopogon citratus (RCC) was found to be highly effective, nontoxic, environmental friendly and low cost adsorbent for the removal of toxic Cd(II) ions from aqueous solution.


2020 ◽  
Vol 10 (1) ◽  
pp. 22-32
Author(s):  
Abdoulaye Demba N'diaye ◽  
Youcef Aoulad El Hadj Ali ◽  
Mohamed Abdallahi Bollahi ◽  
Mostafa Stitou ◽  
Mohamed Kankou ◽  
...  

In this work, batch adsorption experiments were carried out for the removal of Methylene Blue (MB) from aqueous solutions using Typha australis leaf as a low cost adsorbent. The effects of some variables governing the efficiency of the process such as adsorbent mass, pH, ionic strength, contact time and temperature were investigated. The adsorption kinetic data were analyzed using the Pseudo First Order (PFO) and Pseudo Second Order (PSO) models. The experimental equilibrium data were analyzed using Langmuir and Freundlich isotherm models. The results show that the PSO model is the best for describing the adsorption of MB by Typha australis for all initial MB concentrations. The equilibrium data fitted well with the Langmuir model with the monolayer adsorption capacity for MB-Typha australis leaf system was of 103.12 mg g-1. The values of activation parameters such as free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) were also determined as - 4.44 kJ mol−1, 55.13 kJ mol−1 and 203.21 J mol−1 K−1, respectively. The thermodynamics parameters of MB-Typha australis system indicate spontaneous and endothermic process. These results indicate that the Typha australis leaf can be feasibly employed for the eradication of MB from aqueous solution.


2020 ◽  
Vol 20 (3) ◽  
pp. 1907-1916
Author(s):  
Xiaofang Ruan ◽  
Ruyi Li ◽  
Zhexu Ding ◽  
Jun Luo ◽  
Qilin Liu ◽  
...  

In the present study, a novel microbial nanocomposite “Paecilomyces lilacinus-silica nanoparticlescalcium-alginate beads” (P. lilacinus-SN-Cal-Alg) were synthesized and their high efficiency for removing Pb(II) ions was demonstrated in aqueous solution. P. lilacinus-SN-Cal-Alg beads before and after the adsorption of Pb(II) were characterized by FT-IR, SEM-EDS, and XPS analyses. The adsorption capacity of Pb(II) by P. lilacinus-SN-Cal-Alg beads was analyzed in aqueous solution. For comparison, the adsorption capacity of Pb(II) by another type of microbial composites, namely, P. lilacinus-Cal-Alg beads, without addition of silica nanoparticles, was also studied in parallel. Lastly, the equilibrium data in adsorption process were examined by both Langmuir and Freundlich isotherm models to evaluate adsorption mechanism. The results showed that an excellent removal efficiency of Pb(II) in aqueous solution (85.54%) was obtained at initial concentration of 200 mg/L by using the P. lilacinus-SN-Cal-Alg beads. Meanwhile, they exhibited the better adsorption capacity for Pb(II) than P. lilacinus-Cal-Alg beads. The adsorption process by P. lilacinus-SN-Cal-Alg beads was best described by the Langmuir model indicating that monolayer adsorption of Pb(II) ions takes place on the beads surfaces and showed that its maximum adsorption capacity was 282.49 mg/g.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Murat Erdem ◽  
Suat Ucar ◽  
Selhan Karagöz ◽  
Turgay Tay

The removal of lead (II) ions from aqueous solutions was carried out using an activated carbon prepared from a waste biomass. The effects of various parameters such as pH, contact time, initial concentration of lead (II) ions, and temperature on the adsorption process were investigated. Energy Dispersive X-Ray Spectroscopy (EDS) analysis after adsorption reveals the accumulation of lead (II) ions onto activated carbon. The Langmuir and Freundlich isotherm models were applied to analyze equilibrium data. The maximum monolayer adsorption capacity of activated carbon was found to be 476.2 mg g−1. The kinetic data were evaluated and the pseudo-second-order equation provided the best correlation. Thermodynamic parameters suggest that the adsorption process is endothermic and spontaneous.


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