scholarly journals Defluoridation of groundwater using mixed Mukondeni clay soils

2016 ◽  
Vol 17 (2) ◽  
pp. 480-492 ◽  
Author(s):  
T. Ngulube ◽  
M. W. Gitari ◽  
H. Tutu
Keyword(s):  
Fluoride Concentration ◽  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Exchange Capacity ◽  
Clay Soils ◽  
Point Of Zero Charge ◽  
X Ray ◽  
Temperature Optimization ◽  
Pseudo Second Order ◽  
Defluoridation Of Water

Excess fluoride in drinking water is harmful to human health and therefore it needs to be removed from water before consumption. The potential of locally available mixed Mukondeni clay soils (MMCS) as a cheap adsorbent for the removal of fluoride from aqueous solution was investigated. Characterization of MMCS was done by X-ray fluorescence, X-ray diffraction, scanning electron microscopy, Fourier transform infrared and Brunauer Emmett Teller. Cation exchange capacity and point of zero charge of the clays were determined using standard methods. Parameters optimized included: contact time, adsorbent dosage, initial fluoride concentration, pH and temperature. Optimization experiments were done in batch procedures. The results showed that the optimum conditions for the defluoridation of water using MMCS are 60 min, 1.5 g, 9 mg/L, 1.5/100 S/L ratios, pH of 2 and a temperature of 25 °C. The equilibrium isotherm regression parameter (R2 = 0.95) showed that the Freundlich isotherm gave a better fit than the Langmuir isotherm (R2 = 0.52) which indicates multilayer adsorption. Kinetic studies revealed that the adsorption followed pseudo second order kinetics. This study indicated that locally available MMCS are good in the defluoridation of groundwater but modification through blending with metal oxide modified clays can enhance their adsorption capacity.

scholarly journals Adsorption, Kinetic, Equilibrium, Thermodynamic and Photocatalytic Investigations of the Removal of Nigrosin, Alizarin, Indigo and Acid Fuchsin Dyes on Modified CaO Surface

2020 ◽  
pp. 19-32
Author(s):  
Mouayed A. Hussein ◽  
Ibtighaa K. Radhi ◽  
Zaki N. Kadhim
Keyword(s):  
Indigo Carmine ◽  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Acid Fuchsin ◽  
X Ray Diffraction ◽  
Alizarin Red ◽  
Photocatalytic Ability ◽  
X Ray ◽  
Adsorption Processes ◽  
Pseudo Second Order

Calcium oxide was obtained from eggshell and modified with Sulfur, Nitrogen and, Oxygen. The adsorbents were characterized using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and, scanning electron microscopy (SEM). The adsorbents were used for the removing of the dyes of Nigrosin, Alizarin red S, Indigo carmine, and Acid fuchsin from their aqueous solutions. The adsorption isotherm experiments were studied, and the equilibrium adsorption found either obeyed the Langmuir or Freundlich isotherm depending on the Sips isotherm results. Thermodynamic studies showed that the adsorption processes of the studied dyes were spontaneous, endothermic and randomness increases according to their ΔG, ΔH and ΔS values, respectively. The kinetic studies revealed that the pseudo second-order model best represented adsorption kinetics. Moreover, the photocatalytic ability of adsorbents was investigated under the sunlight, the results revealed the adsorbents have a strong photo-catalytic ability to absorb the dyes, particularly that observed for Acid fuchsin.

scholarly journals ADSORPTION AND KINETIC STUDIES OF A NATURAL DYE FROM CURCUMA LONGA L., ONTO BAMBOO YARN

2017 ◽  
Vol 2 (1) ◽  
pp. 13-26
Author(s):  
Tengku Khamanur Azma Tg. Mohd Zamri ◽  
Mimi Sakinah Abd Munaim ◽  
Zularisam Ab Wahid
Keyword(s):  
Adsorption Process ◽  
Regression Coefficient ◽  
Curcuma Longa ◽  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Natural Dye ◽  
Isotherm Models ◽  
Order Model ◽  
Dyeing Process ◽  
Pseudo Second Order

Natural dye extracted from the rhizome of Curcuma longa L. were applied to bamboo yarns using exhaustion dyeing process. This study investigates the dyeing behaviour of Curcumin; the major color component isolated from rhizomes of Curcuma longa L.on bamboo yarn. Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich isotherm models were used to test the adsorption process of curcumin on bamboo yarn. Comparison of regression coefficient value indicated that the Freundlich isotherm most fitted to the adsorption of curcumin onto bamboo yarn. Furthermore, the kinetics study on this research fitted the pseudo-second order model which indicates that the basis of interaction was chemical adsorption.

scholarly journals Synthesis of acid treated carbonized mandarin peel for purification of copper

2020 ◽  
Vol 15 (2) ◽  
pp. 460-471
Author(s):  
T. Unugul ◽  
F. U. Nigiz
Keyword(s):  
Contact Time ◽  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Adsorption Kinetic ◽  
Adsorption Behaviour ◽  
Solution Ph ◽  
Copper Adsorption ◽  
Adsorbent Dosage ◽  
Mandarin Peel ◽  
Pseudo Second Order

Abstract In this study; acid treated carbonized mandarin peel (CMP) adsorbent was prepared and the adsorption behaviour of the adsorbent for copper removal was investigated. In the adsorption studies the effects of initial metal concentration, solution pH, adsorbent dosage and contact time on the removal were investigated. As a result; the highest removal of 100% was achieved when the copper concentration in water was 5 mg/L and the adsorbent dosage was 3.75 g/L at a solution pH of 7. Isotherm studies were also done and the appropriate isotherm was obtained as the Freundlich isotherm. According to the kinetic studies, the copper adsorption onto CMP adsorbent was adopted to the pseudo-second-order adsorption kinetic. After HCl regeneration, the adsorbent maintained 94% of its activity.

scholarly journals The Removal of Uranium and Thorium from Their Aqueous Solutions by 8-Hydroxyquinoline Immobilized Bentonite

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 626 ◽  
Author(s):  
Salah ◽  
Gaber ◽  
Kandil
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Langmuir Isotherm ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
X Ray ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The sorption of uranium and thorium from their aqueous solutions by using 8-hydroxyquinoline modified Na-bentonite (HQ-bentonite) was investigated by the batch technique. Na-bentonite and HQ-bentonite were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier Transform Infrared (FTIR) spectroscopy. Factors that influence the sorption of uranium and thorium onto HQ-bentonite such as solution pH, contact time, initial metal ions concentration, HQ-bentonite mass, and temperature were tested. Sorption experiments were expressed by Freundlich and Langmuir isotherms and the sorption results demonstrated that the sorption of uranium and thorium onto HQ-bentonite correlated better with the Langmuir isotherm than the Freundlich isotherm. Kinetics studies showed that the sorption followed the pseudo-second-order kinetic model. Thermodynamic parameters such as ΔH°, ΔS°, and ΔG° indicated that the sorption of uranium and thorium onto HQ-bentonite was endothermic, feasible, spontaneous, and physical in nature. The maximum adsorption capacities of HQ-bentonite were calculated from the Langmuir isotherm at 303 K and were found to be 63.90 and 65.44 for U(VI) and Th(IV) metal ions, respectively.

scholarly journals Purification, Characterization, and Time-Dependent Adsorption Studies of Ghanaian Muscovite Clay

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Samuel Tetteh ◽  
Andrews Quashie ◽  
Michael Akrofi Anang
Keyword(s):  
Exchange Capacity ◽  
Time Dependent ◽  
Point Of Zero Charge ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Studies ◽  
Morphological Studies ◽  
Ft Ir ◽  
Crystalline Nature ◽  
Different Parts

Three clay samples (E1, E2, and C1) extracted from different parts of Ghana have been purified by sedimentation. The samples were further characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), cation exchange capacity (CEC), and point of zero charge (pHpzc). PXRD and FT-IR data revealed the samples to be predominantly muscovite clay with percentages ranging from 82.71 to 91.33%. The surfaces were mostly cationic with pHpzc ranging from 5.58 to 6.40. Morphological studies by SEM confirmed the crystalline nature of the surfaces which is suitable for adsorption studies. Time-dependent adsorption studies show that C1 is a good candidate for the adsorption of chlorophenols, methyl orange, and Eriochrome Black T.

scholarly journals Sequestration of Pb(II) Ions from Aqueous Systems with Novel Green Bacterial Cellulose Graphene Oxide Composite

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 218 ◽  
Author(s):  
Alfred Mensah ◽  
Pengfei Lv ◽  
Christopher Narh ◽  
Jieyu Huang ◽  
Di Wang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Bacterial Cellulose ◽  
Kinetic Studies ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carboxylate Groups ◽  
Green Adsorbent ◽  
Pseudo Second Order ◽  
Very High

In this study, a novel green adsorbent material prepared by the esterification of bacterial cellulose (BC) and graphene oxide (GO), richly containing hydroxyl, alkyl, and carboxylate groups was characterised by FTIR (Fourier Transform infrared spectroscopy), XRD (X-ray diffraction), SEM (Scanning electron microscopy) and TGA (Thermo-graphimetric analysis). The specific surface area (SSA) and pore size distribution (PSD) analysis of materials were also analysed. Batch experiments–adsorption studies confirmed the material to have a very high Pb2+ removal efficiency of over 90% at pH 6–8. Kinetic studies showed that the uptake of metal ions was rapid with equilibrium attained after 30 min and fitted well with the pseudo-second-order rate model (PSO). Isotherm results with a maximum adsorption capacity (Qmax) of 303.03 mg/g were well described by Langmuir’s model compared to Freundlich. Desorption and re-adsorption experiments realised that both adsorbent and adsorbates could be over 90–95% efficiently recovered and reused using 0.1 M HNO3 and 0.1 M HCl.

scholarly journals Parametric, equilibrium and kinetic studies on the removal of mercury using ion exchange resin

2017 ◽  
Vol 12 (2) ◽  
pp. 305-313 ◽  
Author(s):  
N. Rajamohan ◽  
M. Rajasimman
Keyword(s):  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Strong Acid ◽  
Ion Exchange Resin ◽  
Second Order ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Acid Cation ◽  
Pseudo Second Order ◽  
Langmuir Constants

This experimental research was an investigation into removal of mercury by using a strong acid cation resin, 001 × 7. Parametric experiments were conducted to determine the optimum pH, resin dosage, agitation speed and the effect of change in concentration in the range of 50–200 mg/L. High resin dosages favoured better removal efficiency but resulted in lower uptakes. Equilibrium experiments were performed and fitted to Langmuir and Freundlich isotherm models. Langmuir model suited well to this study confirming the homogeneity of the resin surface. The Langmuir constants were estimated as qmax = 110.619 mg/g and KL = 0.070 L/g at 308 K. Kinetic experiments were modeled using Pseudo second order model and higher values of R2 (>0.97) were obtained. The Pseudo second order kinetic constants, namely, equilibrium uptake (qe) and rate constant (k2), were evaluated as 59.17 mg/g and 40.2 × 10−4 g mg−1 min−1 at an initial mercury concentration of 100 mg/L and temperature of 308 K.

Adsorptive removal of PPCPs by biomorphic HAP templated from cotton

2016 ◽  
Vol 74 (1) ◽  
pp. 276-286 ◽  
Author(s):  
Bin Huang ◽  
Dan Xiong ◽  
Tingting Zhao ◽  
Huan He ◽  
Xuejun Pan
Keyword(s):  
Adsorption Mechanism ◽  
Adsorption Process ◽  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Precipitation Method ◽  
Adsorptive Removal ◽  
Transmission Electron ◽  
Initial Ph ◽  
Pseudo Second Order ◽  
Co Precipitation

Biomorphic nano-hydroxyapatite (HAP) was fabricated by a co-precipitation method using cotton as bio-templates and employed in adsorptive removal of ofloxacin (OFL) and triclosan (TCS) that are two representative pharmaceuticals and personal care products (PPCPs). The surface area and porosity, crystal phase, functional group, morphology and micro-structure of the synthesized HAP were characterized by Brunauer–Emmett–Teller isotherm, X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron macroscopic and transmission electron microscopy. The effects of initial pH, ionic strength, initial concentration, contact time and temperature on the removal of PPCPs were studied in a batch experiment. The adsorption of OFL and TCS was rapid and almost accomplished within 50 min. Kinetic studies indicated that the adsorption process of OFL and TCS followed the pseudo-first-order and pseudo-second-order models, respectively. The Freundlich isotherm described the OFL adsorption process well but the adsorption of TCS fitted the Langmuir isotherm better. Thermodynamics and isotherm parameters suggested that both OFL and TCS adsorption were feasible and spontaneous. Hydrogen bond and Lewis acid–base reaction may be the dominating adsorption mechanism of OFL and TCS, respectively. Compared to other adsorbents, biomorphic HAP is environmentally friendly and has the advantages of high adsorption capacity, exhibiting potential application for PPCPs removal.

Removal of fluoride from aqueous solution by adsorption onto Kanuma mud

2010 ◽  
Vol 62 (8) ◽  
pp. 1888-1897 ◽  
Author(s):  
Nan Chen ◽  
Zhenya Zhang ◽  
Chuanping Feng ◽  
Miao Li ◽  
Rongzhi Chen ◽  
...  
Keyword(s):  
Adsorption Process ◽  
Fluoride Concentration ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
Solution Ph ◽  
Intra Particle Diffusion ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Solid Liquid Interface ◽  
Solid Liquid

Kanuma mud, a geomaterial, is used as an adsorbent for the removal of fluoride from water. The influences of contact time, solution pH, adsorbent dosage, initial fluoride concentration and co-existing ions were investigated by batch equilibration studies. The rate of adsorption was rapid with equilibrium being attained after about 2 h, and the maximum removal of fluoride was obtained at pH 5.0–8.0. The Freundlich isotherm model was found to represent the measured adsorption data well. The negative value of the thermodynamic parameter ΔG suggests the adsorption of fluoride by Kanuma mud was spontaneous, the endothermic nature of adsorption was confirmed by the positive ΔH value. The negative ΔS value for adsorbent denoted decreased randomness at the solid/liquid interface. The adsorption process using Kanuma mud followed the pseudo-second-order kinetic model. Fluoride uptake by the Kanuma mud was a complex process and intra-particle diffusion played a major role in the adsorption process. It was found that adsorbed fluoride could be easily desorbed by washing the adsorbent with a solution of pH 12. This indicates the material could be easily recycled.

Removal of Pb (II) from Aqueous Solution by Blast-Furnace Slags

2013 ◽  
Vol 726-731 ◽  
pp. 2736-2741
Author(s):  
Ming Da Liu ◽  
Ge Tian ◽  
Liang Jie Zhao ◽  
Yao Sheng Wang ◽  
Lei Guo ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Blast Furnace ◽  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Sorption Process ◽  
Second Order ◽  
Order Model ◽  
Pseudo Second Order ◽  
Solution Kinetic ◽  
Second Order Model

Five blast-furnace slags were used as adsorbents to remove Pb (II) from aqueous solution. Kinetic studies showed that the sorption process was best described by pseudo-second-order model. Among Langmuir, Freundlich and Temkin isotherms, the Freundlich isotherm had a better fit with the simulation of the adsorption of Pb (II).

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