Fixed-Bed Adsorption: Comparisons of Virgin and Zirconium Oxide-Coated Scoria for the Removal of Fluoride from Water

Geleta, Wondwosen Sime; Alemayehu, Esayas; Lennartz, Bernd

doi:10.3390/molecules27082527

Cited by 6 publications

(1 citation statement)

References 60 publications

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“…Several studies have investigated diverse sorbents for the defluoridation process. These include fly ash, activated and amorphous alumina, zirconium oxide, calcite, activated carbon from different biomass, clay minerals, agricultural wastes, rare earth oxide, charcoal, pumice and volcanic rock materials 13 – 15 . These materials are readily available in the environment but their adsorption capacity is normally not efficient, hence, better and more efficient adsorbents need to be developed 16 .…”

Section: Introductionmentioning

confidence: 99%

Understanding fluoride adsorption from groundwater by alumina modified with alum using PHREEQC surface complexation model

Adu-Boahene

Boakye

Agyemang

et al. 2023

Sci Rep

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Fluoride is recognized as a vital ion for human and animal growth because of the critical role it plays in preventing skeletal and dental problems. However, when it is ingested at a higher concentration it can cause demineralization of teeth and bones resulting in fluorosis, therefore, the production of high-adsorptive capacity material which is also cost-effective is necessary for the treatment of fluorides. In this study, aluminium foil is valorised into alumina nanoparticles. The as-prepared alumina was modified with alum in two different ratios of 1:0.5 and 1:1 (alumina to alum w/w%) and later used as adsorbents for the removal of fluoride from groundwater. The adsorbents were characterized by Fourier transform infrared spectroscopy, point of zero charge and X-ray diffraction. Different factors that influence the removal efficiency of fluorides such as pH, initial concentrations, contact time and adsorbent dosage were studied and optimized using a simulated fluoride solution. The optimum conditions obtained were used to test real groundwater. The static experiment conditions were used to calibrate a PHREEQC geochemical model which was later used to simulate the fluoride sorption onto the modified alumina at different conditions. PHREEQC was also coupled with parameter estimation software to determine equilibrium constants for the surface reactions between the fluoride species and the adsorbent in a way that the simulations accurately reflect the outcomes of laboratory experiments. Isotherm studies were carried out on the adsorbents. Both Langmuir and Freundlich's non-linear models fitted well for the equilibrium data. However, with a higher coefficient of regression and low chi-square test values, the adsorption process was more of chemisorption on a monolayer surface. Kinetic studies were also carried out by using the non-linear equations from the pseudo-first-order and pseudo-second-order models. The pseudo-second-order model fitted well for the equilibrium data. The mechanism for the fluoride ion adsorption was also studied by the intraparticle (IP) diffusion model and was found that IP was not the rate-determining factor, and therefore the most plausible mechanism for the sorption process was ion exchange or attraction of fluoride ions to the sorbent surface. The findings obtained from this research show that readily available aluminium waste could be valorised into a useful product that could be employed in the removal of fluoride from water samples, including groundwater, that may contain too much fluoride and pose a risk to the general public's health.

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Section: Introductionmentioning

confidence: 99%

Understanding fluoride adsorption from groundwater by alumina modified with alum using PHREEQC surface complexation model

Adu-Boahene

Boakye

Agyemang

et al. 2023

Sci Rep

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Application of artificial neural network for prediction of fluoride removal efficiency using neutralized activated red mud from aqueous medium in a continuous fixed bed column

Giri

Mishra

2022

Environ Sci Pollut Res

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The present research work approaches the removal of uoride from aqueous medium using neutralized activated red mud (NARM) in a continuous xed bed column. Arti cial neural network (ANN) technique was applied effectively for optimization of the model for the practicability of the removal process. The consequences of various experimental variables like bed length, adsorbate concentration, experimental time and adsorbate solution ow rate studied to know the breakthrough point and saturation times. The highest removal potentiality of NARM was considered to be 3.815 mg g − 1 of F − in the bed height of 15 cm, starting concentration 1ppm, susceptible time 120 minutes, adsorbate solution ow rate 0.5 mLmin − 1 , and constant room temperature, respectively. Bohart-Adams and Thomas models were considered to describe the xed bed column effect to the bed height and adsorbate concentrations. The experimental data were applied a back propagation (BP) learning algorithm programme with four-seven-one architecture model. The arti cial neural network model was considered to be functioning correctly as absolute relative percentage error, which is 0.671 throughout the learning period. Differentiation between the predicted out comes from ANN model and actual results from experimental analysis affords a high degree of correlation (R 2 = 0.998) stipulating that the model was able to predict the adsorption e ciency. Experimented adsorbent materials was characterized using different instrumental analysis that is SEM-EDS, FTIR and XRD.

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Application of iron oxides modified volcanic rock in continuous phenol wastewater anaerobic treatment: Performance and underlying mechanisms

Zhang,

Chen,

Dou

et al. 2023

Renewable Energy

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Fixed-Bed Adsorption: Comparisons of Virgin and Zirconium Oxide-Coated Scoria for the Removal of Fluoride from Water

Cited by 6 publications

References 60 publications

Understanding fluoride adsorption from groundwater by alumina modified with alum using PHREEQC surface complexation model

Understanding fluoride adsorption from groundwater by alumina modified with alum using PHREEQC surface complexation model

Application of artificial neural network for prediction of fluoride removal efficiency using neutralized activated red mud from aqueous medium in a continuous fixed bed column

Application of iron oxides modified volcanic rock in continuous phenol wastewater anaerobic treatment: Performance and underlying mechanisms

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