scholarly journals Defluoridation of groundwater using mechanochemically-activated clay soil

2018 ◽  
Vol 13 (3) ◽  
pp. 599-611
Author(s):  
Masindi E. Denga ◽  
Wilson M. Gitari ◽  
Anthony A. Izuagie ◽  
Segun A. Akinyemi
Keyword(s):  
Milling Time ◽  
Clay Soil ◽  
Fluoride Removal ◽  
Order Kinetic ◽  
Physicochemical Transformation ◽  
X Ray ◽  
Freundlich Isotherms ◽  
Peak Broadening ◽  
Pseudo Second Order ◽  
High Concentrations

Abstract High concentrations of fluoride in drinking water are reported to be hazardous to human health. This study was conducted to assess the efficiency of mechanochemically-activated aluminosilicate clay soil in removing fluoride from groundwater. The soil was subjected to physicochemical transformation through mechanochemical activation for different time intervals (5, 10, 15 and 30 min). The highest specific surface obtained was about 50 m2/g, with the sample activated for 30 minutes. Fourier Transform Infrared (FT-IR) analyses of samples showed an increase in absorbance by Si-O-H groups at 510 cm−1 with increasing milling time. X-ray diffraction (XRD) analyses revealed that, at 30 minutes milling time, peak broadening was intensified while reflection peak intensities decreased. X-ray fluorescence (XRF) spectrometry showed that silica and alumina were the major clay soil components. Using a dosage of 0.6 g/100 mL of activated clay, a maximum fluoride removal of 41% was achieved using the batch activated for 30 minutes on water spiked with 9 mg-F/L at pH 2.41. The adsorption data fitted both the Langmuir and Freundlich isotherms, but only the pseudo-second-order kinetic, showing chemisorption fluoride removal.

scholarly journals Comparison of Rhodotorula sp. and Bacillus megaterium in the removal of cadmium ions from liquid effluents

2018 ◽  
Vol 7 (1) ◽  
pp. 74-88 ◽  
Author(s):  
Mihaela Roşca ◽  
Raluca-Maria Hlihor ◽  
Petronela Cozma ◽  
Elena Niculina Drăgoi ◽  
Mariana Diaconu ◽  
...  
Keyword(s):  
Bacillus Megaterium ◽  
Contact Time ◽  
Point Of Zero Charge ◽  
Operating Parameters ◽  
Order Kinetic ◽  
Cadmium Ions ◽  
X Ray ◽  
Freundlich Isotherms ◽  
Accuracy And Precision ◽  
Pseudo Second Order

AbstractThis study compares the capacity ofRhodotorulasp. andBacillus megateriumfor Cd(II) removal considering the influence of operating parameters (pH, biosorbent dosage, contact time, temperature, initial metal concentration in solution). The highest Cd(II) uptake of 14.2 mg/g byRhodotorulasp. was exhibited at 30°C, when working at pH 6 and with 5 g/l biosorbent dosage, after 48 h of contact time. In these conditions, a removal efficiency of 85% was obtained. Similar outcomes were obtained forB. megaterium(15.1 mg/g, 90%) at 35°C, pH 4 and 3 g/l biosorbent dosage, considered as the optimum set of parameters, equilibrium being achieved for a contact time of 20 min. The possible interaction mechanisms between the biosorbents and Cd(II) were evaluated through point of zero charge (pHpzc), Fourier transform infrared (FTIR), spectroscopy and scanning electron microscopy coupled with energy dispersive X-ray microanalysis (SEM-EDX). Data were modeled using pseudo-first and pseudo-second order kinetic models and Langmuir and Freundlich isotherms models. Further studies considered a modeling approach based on linear regression with Durbin-Watson statistics, while the accuracy and precision of experiments were evaluated by ANOVA.

scholarly journals Adsorptive Removal of Cd, Cu, Ni and Mn from Environmental Samples Using Fe3O4-Zro2@APS Nanocomposite: Kinetic and Equilibrium Isotherm Studies

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3209
Author(s):  
Aphiwe Siyasanga Gugushe ◽  
Anele Mpupa ◽  
Tshimangadzo Saddam Munonde ◽  
Luthando Nyaba ◽  
Philiswa Nosizo Nomngongo
Keyword(s):  
Electron Microscopy ◽  
Magnetic Nanomaterials ◽  
Batch Mode ◽  
X Ray ◽  
Freundlich Isotherms ◽  
Adsorption Capacities ◽  
Transmission Electron ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Wastewater Samples

In this study, Fe3O4-ZrO2 functionalized with 3-aminopropyltriethoxysilane (Fe3O4-ZrO2@APS) nanocomposite was investigated as a nanoadsorbent for the removal of Cd(II), Cu(II), Mn (II) and Ni(II) ions from aqueous solution and real samples in batch mode systems. The prepared magnetic nanomaterials were characterized using X-ray powder diffraction (XRD), scanning electron microscopy/energy dispersion x-ray (SEM/EDX) Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). Factors (such as adsorbent dose and sample pH) affecting the adsorption behavior of the removal process were studied using the response surface methodology. Under optimized condition, equilibrium data obtained were fitted into the Langmuir and Freundlich isotherms and the data fitted well with Langmuir isotherms. Langmuir adsorption capacities (mg/g) were found to be 113, 111, 128, and 123 mg/g for Cd, Cu, Ni and Mn, respectively. In addition, the adsorption kinetics was analyzed using five kinetic models, pseudo-first order, pseudo-second order, intraparticle diffusion and Boyd models. The adsorbent was successfully applied for removal of Cd(II), Cu(II), Mn (II) and Ni(II) ions in wastewater samples.

scholarly journals Characterisation of smectite-rich clay soil: Implication for groundwater defluoridation

2016 ◽  
Vol Volume 112 (Number 11/12) ◽  
Author(s):  
Rabelani Mudzielwana ◽  
Mugera W. Gitari ◽  
Titus A.M. Msagati ◽  
◽  
◽  
...  
Keyword(s):  
South Africa ◽  
Rural Areas ◽  
Contact Time ◽  
Clay Soil ◽  
Dental Fluorosis ◽  
Fluoride Concentration ◽  
Limpopo Province ◽  
World Health ◽  
Fluoride Removal ◽  
X Ray

Abstract Groundwater is a widely used and affordable source of drinking water in most of the rural areas of South Africa. Several studies have indicated that groundwater in some boreholes in South Africa has a fluoride concentration above the level recommended by the World Health Organization (1.5 mg/L). Fluoride concentrations above the permissible limit (>1.5 mg/L) lead to dental fluorosis, with even higher concentrations leading to skeletal fluorosis. In the present work, we evaluate the application of smectite-rich clay soil from Mukondeni (Limpopo Province, South Africa) in defluoridation of groundwater. The clay soil was characterised by mineralogy using X-ray diffraction, by elemental composition using X-ray fluorescence and by morphology using scanning electron microscopy. Surface area and pore volume was determined by the Brunauer–Emmett–Teller surface analysis method. Cation exchange capacity and pHpzc of the soil were also evaluated using standard laboratory methods. Batch experiments were conducted to evaluate and optimise various operational parameters such as contact time, adsorbent dose, pH and initial adsorbate concentration. It was observed that 0.8 g/100 mL of smectite-rich clay soil removed up to 92% of fluoride from the initial concentration of 3 mg/L at a pH of 2 with a contact time of 30 min. The experimental data fitted well to a Langmuir adsorption isotherm and followed pseudo second order reaction kinetics. Smectite-rich clay soil showed 52% fluoride removal from field groundwater with an initial fluoride concentration of 5.4 mg/L at an initial pH of 2 and 44% removal at a natural pH of 7.8. Therefore smectite-rich clay soil from Mukondeni has potential for application in defluoridation of groundwater. Chemical modification is recommended to improve the defluoridation capacity.

scholarly journals Adsorption purification of waste water from chromium by ferrite manganese

2020 ◽  
Vol 168 ◽  
pp. 00026
Author(s):  
Liliia Frolova ◽  
Mykola Kharytonov ◽  
Iryna Klimkina ◽  
Oleksandr Kovrov ◽  
Andrii Koveria
Keyword(s):  
Adsorption Process ◽  
Uv Spectroscopy ◽  
Second Order ◽  
Waste Waters ◽  
Equilibrium Isotherms ◽  
X Ray ◽  
First Order ◽  
Freundlich Isotherms ◽  
Pseudo Second Order ◽  
Kinetics Of

Plasma method is used to synthesize manganese ferrite. The basic properties of ferrite are determined by IR spectroscopy, UV spectroscopy, X-ray phase analysis, vibration magnetometry. The paper shows that the use of magnetically controlled sorbent allows to purify waste waters from chromium (III). The process of adsorption of chromium cations (III) is investigated. The kinetics of the process is studied. To describe the equilibrium isotherms, the experimental data are analysed by the models of Langmuir, Freundlich isotherms. Pseudo-first order, pseudo-second-order, and Weber-Morris are used to elucidate the kinetic parameters and mechanism of the adsorption process. It has been established that the removal of Cr (III) cations is described by the pseudo-second order of the Langmuir reaction and mechanism.

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.

Adsorption of fluoride from aqueous solution using low cost adsorbent

2013 ◽  
Vol 13 (2) ◽  
pp. 238-248 ◽  
Author(s):  
R. Buamah ◽  
R. Asare Mensah ◽  
A. Salifu
Keyword(s):  
Drinking Water ◽  
Low Cost ◽  
Northern Ghana ◽  
Fluoride Removal ◽  
Order Kinetic ◽  
X Ray ◽  
Removal Capacity ◽  
Removal Technologies ◽  
High Aluminium ◽  
Model Water

High fluoride levels beyond the recommended value of 1.5 mg/L have been detected in several groundwater wells in Northern Ghana. This occurrence has led to the capping of many high yielding wells that hitherto have been major sources of drinking water for the populace in these arid areas. Most of the fluoride removal technologies applied in the area has not been versatile in effectively removing fluoride because of the varying water qualities. This study focused on screening adsorbents including high aluminium or iron containing bauxite ores, fabricated zeolite and activated Neem seeds for removal of fluoride from drinking water. The model water used was prepared by simulating the prevailing groundwater quality in Northern Ghana. The high aluminium bauxite ore (HABO) had the highest fluoride removal capacity. Within the pH range tested (5–7), the fluoride removal decreased with increasing pH. Occurrence of sulfate, chloride and nitrate in the model water reduced the fluoride removal capacity by 57, 24 and 38% respectively. The combined effect of these anions showed a 60% reduction in the fluoride removal capacity. The Freundlich and Langmuir isotherms gave an adsorption capacity (K) of 0.90 mg/g for the HABO. The adsorption kinetics fitted well the pseudo second-order kinetic model. The HABO is thermally stable and has kaolinite [Al2Si2O5(OH)5] and gibbsite [Al(OH)3] as its major components. X-ray fluorescence (XRF) and energy dispersive X-ray (EDX) results showed Al, Fe, Ti, O, C and Si as the predominant elements in the HABO.

Chromate sorption and reduction kinetics onto an aminated biosorbent

2006 ◽  
Vol 54 (10) ◽  
pp. 1-8 ◽  
Author(s):  
S. Deng ◽  
Y.P. Ting ◽  
G. Yu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Penicillium Chrysogenum ◽  
Sorption Process ◽  
Sorption Kinetics ◽  
Order Kinetic ◽  
Chromium Species ◽  
X Ray ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Amine Groups

A novel biosorbent was prepared by chemically grafting of polyethylenimine (PEI) onto the fungal biomass of Penicillium chrysogenum through a two-step reaction. The modified biosorbent is favorable for the removal of anionic Cr(VI) species from aqueous solution due to the protonation of amine groups on the biomass surface. The sorption capacity for Cr(VI) increased by 7.2-fold after surface modification. Sorption kinetics results show that the pseudo-second-order kinetic model described the experimental data well. During the sorption process, X-ray photoelectron spectroscopy (XPS) was used to analyze the chromium species on the biosorbent surface and the results indicate that part of the Cr(VI) ions were reduced to Cr(III) ions which can be chelated with the amine groups on the biomass surface. The reduced Cr(III) ions formed some aggregates on the surface at higher solution pHs.

scholarly journals Mechanosynthesis of MFe2O4 (M = Co, Ni, and Zn) Magnetic Nanoparticles for Pb Removal from Aqueous Solution

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
America R. Vazquez-Olmos ◽  
Mohamed Abatal ◽  
Roberto Y. Sato-Berru ◽  
G. K. Pedraza-Basulto ◽  
Valentin Garcia-Vazquez ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Xrd Analysis ◽  
Maximum Adsorption Capacity ◽  
Sorption Behavior ◽  
Order Kinetic ◽  
X Ray ◽  
Isotherm Adsorption ◽  
Crystallite Sizes ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order

Adsorption of Pb(II) from aqueous solution using MFe2O4 nanoferrites (M = Co, Ni, and Zn) was studied. Nanoferrite samples were prepared via the mechanochemical method and were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), micro-Raman, and vibrating sample magnetometry (VSM). XRD analysis confirms the formation of pure single phases of cubic ferrites with average crystallite sizes of 23.8, 19.4, and 19.2 nm for CoFe2O4, NiFe2O4, and ZnFe2O4, respectively. Only NiFe2O4 and ZnFe2O4 samples show superparamagnetic behavior at room temperature, whereas CoFe2O4 is ferromagnetic. Kinetics and isotherm adsorption studies for adsorption of Pb(II) were carried out. A pseudo-second-order kinetic describes the sorption behavior. The experimental data of the isotherms were well fitted to the Langmuir isotherm model. The maximum adsorption capacity of Pb(II) on the nanoferrites was found to be 20.58, 17.76, and 9.34 mg·g−1 for M = Co, Ni, and Zn, respectively.

Effects of size and surface on luminescence properties of submicron upconversion NaYF4:Yb,Er particles

2009 ◽  
Vol 24 (6) ◽  
pp. 2042-2050 ◽  
Author(s):  
Du Yuan ◽  
Guang Shun Yi ◽  
Gan Moog Chow
Keyword(s):  
Milling Time ◽  
Transition Probability ◽  
Emission Spectra ◽  
Average Particle ◽  
Particle Sizes ◽  
Surface Enrichment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Size Dependent ◽  
Peak Broadening

Bulk NaYF4:Yb,Er particles (∼1.4 μm particle size) were synthesized using a hydrothermal method. As-synthesized particles were subsequently ball milled to three average particle sizes, namely, ∼260 nm, 160 nm, and 100 nm. The x-ray diffraction pattern showed an hcp phase for as-synthesized and ball-milled particles with a predominant (100) peak. Room temperature emission spectra showed no size dependent peak shifts or peak broadening. The intensities of both green and red emissions decreased with increasing milling time. Segregation of Er ions was detected on the surfaces of milled particle that reduced the sensitizer-activator transition probability, resulting in decreased emission intensities. The green-to-red emission ratio was correlated to the surface enrichment of Er, which affected the cross-relaxation of luminescence dynamics.

The sorption of lead, cadmium, copper and zinc ions from aqueous solutions on a raw diatomite from Algeria

2012 ◽  
Vol 65 (10) ◽  
pp. 1729-1737 ◽  
Author(s):  
Messaouda Safa ◽  
Mohammed Larouci ◽  
Boumediene Meddah ◽  
Pierre Valemens
Keyword(s):  
Metal Ions ◽  
Low Cost ◽  
Kinetic Equations ◽  
Sorption Process ◽  
Second Order ◽  
Order Kinetic ◽  
Reaction Conditions ◽  
Freundlich Isotherms ◽  
Pseudo Second Order ◽  
Sorption Parameters

The adsorption of Cu2+, Zn2+, Cd2+ and Pb2+ ions from aqueous solution by Algerian raw diatomite was studied. The influences of different sorption parameters such as contact pH solution, contact time and initial metal ions concentration were studied to optimize the reaction conditions. The metals ions adsorption was strictly pH dependent. The maximum adsorption capacities towards Cu2+, Zn2+, Cd2+ and Pb2+ were 0.319, 0.311, 0.18 and 0.096 mmol g−1, respectively. The kinetic data were modelled using the pseudo-first-order and pseudo-second-order kinetic equations. Among the kinetic models studied, the pseudo-second-order equation was the best applicable model to describe the sorption process. Equilibrium isotherm data were analysed using the Langmuir and the Freundlich isotherms; the results showed that the adsorption equilibrium was well described by both model isotherms. The negative value of free energy change ΔG indicates feasible and spontaneous adsorption of four metal ions on raw diatomite. According to these results, the high exchange capacities of different metal ions at high and low concentration levels, and given the low cost of the investigated adsorbent in this work, Algerian diatomite was considered to be an excellent adsorbent.

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