Adsorptive removal of fluoride using biochar – A potential application in drinking water treatment

Sadhu, Mohini; Bhattacharya, Prosun; Vithanage, Meththika; Sudhakar, P.

doi:10.1016/j.seppur.2021.119106

Cited by 79 publications

(29 citation statements)

References 60 publications

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“… Oladoja and Helmreich (2016) studied the adsorption of fluoride using calcium aluminate–diatomaceous earth composites and found that its adsorption reached equilibrium when the reaction time was 120 min, as found in our study. This is because at the initial stage of adsorption, there are more active sites on the adsorbent surface and so F ‐ rapidly occupies the active sites on the adsorbent’s surface, and its adsorption capacity increases ( Sadhu et al, 2021 ). But when prolonged, the available active sites on the adsorbent’s surface decline significantly, and adsorption gradually spreads to the internal surface of the porous adsorbent, which strengthens its resistance and slows down adsorption such that the adsorption capacity no longer changes ( Akafu et al, 2019 ).…”

Section: Resultsmentioning

confidence: 99%

Adsorption Characteristics and Charge Transfer Kinetics of Fluoride in Water by Different Adsorbents

et al. 2022

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Water containing high concentrations of fluoride is widely distributed and seriously harmful, largely because long-term exposure to fluoride exceeding the recommended level will lead to fluorosis of teeth and bones. Therefore, it is imperative to develop cost-effective and environmentally friendly adsorbents to remove fluoride from polluted water sources. In this study, diatomite (DA), calcium bentonite (CB), bamboo charcoal (BC), and rice husk biochar (RHB) were tested as adsorbents to adsorb fluoride (F‐) from water, and this process was characterized by scanning electron microscopy (FEI-SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). The effects of pH, dosage, and the initial mass concentration of each treatment solution upon adsorption of F‐ were determined. Kinetic and thermodynamic models were applied to reveal the mechanism of defluoridation, and an orthogonal experiment was designed to obtain the optimal combination of conditions. The results show that the surfaces of CB, BC, and RHB have an irregular pore structure and rough surface, whereas DA has a rich pore structure, clear pores, large specific surface area, and high silica content. With regard to the adsorption process for F‐, DA has an adsorption complex electron interaction; that of CB, BC, and RHB occur mainly via ion exchange with positive and negative charges; and CB on F‐ relies on chemical electron bonding adsorption. The maximum adsorption capacity of DA can reach 32.20 mg/g. When the mass concentration of fluoride is 100 mg/L, the pH value is 6.0 and the dosage is 4.0 g/L; the adsorption rate of F‐ by DA can reach 91.8%. Therefore, we conclude that DA soil could be used as an efficient, inexpensive, and environmentally friendly adsorbent for fluoride removal, perhaps providing an empirical basis for improving the treatment of fluorine-containing water in the future.

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Section: Resultsmentioning

confidence: 99%

Adsorption Characteristics and Charge Transfer Kinetics of Fluoride in Water by Different Adsorbents

et al. 2022

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“…The new peak appears at 561 cm −1 , which indicates the presence of Fe–O in Fe 3 O 4 [ 28 ]. After fluoride adsorption, the intensity of the peaks remains the same, and a new peak at 979 cm −1 indicates the C–F stretching [ 26 ]. In addition, the characteristic peak shift at 592 cm −1 indicates the Fe–F bond formation.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, high-quality adsorbents with excellent properties attract more attention. Many adsorbents, such as activated carbon [ 21 ], bone char [ 22 ], zeolite [ 23 ], calcined clay [ 24 ], activated fly ash [ 25 ] and loaded biochar [ 26 ], have been used for water defluoridation. Recently, biochar (BC) has been extensively used as an adsorbent due to its low-budget, eco-friendly nature, and substantial resources [ 27 ].…”

Section: Introductionmentioning

confidence: 99%

Nanoarchitectonics and Kinetics Insights into Fluoride Removal from Drinking Water Using Magnetic Tea Biochar

Ashraf

Chen

et al. 2022

IJERPH

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Fluoride contamination in water is a key problem facing the world, leading to health problems such as dental and skeletal fluorosis. So, we used low-cost multifunctional tea biochar (TBC) and magnetic tea biochar (MTBC) prepared by facile one-step pyrolysis of waste tea leaves. The TBC and MTBC were characterized by XRD, SEM, FTIR, and VSM. Both TBC and MTBC contain high carbon contents of 63.45 and 63.75%, respectively. The surface area of MTBC (115.65 m2/g) was higher than TBC (81.64 m2/g). The modified biochar MTBC was further used to remediate the fluoride-contaminated water. The fluoride adsorption testing was conducted using the batch method at 298, 308, and 318 K. The maximum fluoride removal efficiency (E%) using MTBC was 98% when the adsorbent dosage was 0.5 g/L and the fluoride concentration was 50 mg/L. The experiment data for fluoride adsorption on MTBC best fit the pseudo 2nd order, rather than the pseudo 1st order. In addition, the intraparticle diffusion model predicts the boundary diffusion. Langmuir, Freundlich, Temkin, and Dubnin–Radushkevich isotherm models were fitted to explain the fluoride adsorption on MTBC. The Langmuir adsorption capacity of MTBC= 18.78 mg/g was recorded at 298K and decreased as the temperature increased. The MTBC biochar was reused in ten cycles, and the E% was still 85%. The obtained biochar with a large pore size and high removal efficiency may be an effective and low-cost adsorbent for treating fluoride-containing water.

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“…A sizeable body of work featuring the Halsey isotherm has been published across a broad spectrum of scholarly journals. Quite a large fraction of these reports can be found in several major journals (e.g., Chemical Engineering Journal [2][3][4][5][6][7][8][9][10][11][12], Journal of Hazardous Materials [13][14][15][16][17][18][19][20][21], Separation and Purification Technology [22][23][24][25][26][27][28], and Journal…”

Section: Introductionmentioning

confidence: 99%

The Halsey isotherm for water contaminant adsorption is fake

Chu

Bashiri

Hashim

et al. 2023

Separation and Purification Technology

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Adsorptive removal of fluoride using biochar – A potential application in drinking water treatment

Cited by 79 publications

References 60 publications

Adsorption Characteristics and Charge Transfer Kinetics of Fluoride in Water by Different Adsorbents

Adsorption Characteristics and Charge Transfer Kinetics of Fluoride in Water by Different Adsorbents

Nanoarchitectonics and Kinetics Insights into Fluoride Removal from Drinking Water Using Magnetic Tea Biochar

The Halsey isotherm for water contaminant adsorption is fake

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