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

Abstract

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.

Insights into kinetics, thermodynamics, and mechanisms of chemically activated sunflower stem biochar for removal of phenol and bisphenol-A from wastewater

“…Further, the statistical error and chi-square calculations (Table S2 ) found that Freundlich's model fitting shows a low chi-square value. These results suggest that each adsorption site on the KOH-SSAC surface possesses distinct adsorption energies and affinities for phenol and BPA 41 .…”

Preparation of Lanthanum-Modified Tea Waste Biochar and Its Adsorption Performance on Fluoride in Water

“…Figure 11 shows the FTIR spectra of TBC, La-TBC, and La-TBC-F. Among these, the characteristic peaks of the three biochar materials that appeared at wave number 3442 cm −1 were mainly due to the O-H stretching vibration in the H 2 O on the surface of the materials [40]; the characteristic peaks appearing at wave number of 1628 cm −1 were caused by the vibration of C=O and C=C, which indicates that the carbon composition of the materials was complex [41]; the characteristic peaks appearing at 1384 cm −1 were caused by the vibration of −NO 3 , and the intensity of the characteristic peaks was increased after modification, which implies the presence of nitric oxides, such as nitrate, in the materials [42]. Comparing the TBC spectra, we see that those for La-TBC showed new characteristic absorption peaks at wave numbers of 1493 versus 1042 cm −1 , which can be attributed to the reaction of La(OH) 3 with the CO 2 in air to form carbonate groups [43], and the peak at 739 cm −1 can be attributed to the La-OH vibration [32], indicating that lanthanum (La) has been successfully loaded.…”

Multivariate Analysis of Harvested Rainwater Quality Utilizing Sustainable Solar-Energy-Driven Water Treatment

“…Various low-cost, high-efficiency, and environmentally friendly methods are emerging techniques used to treat water for drinking purposes, specifically focusing on their relevance in developing countries. For example, Ashraf et al [8] proposed a renewable technique using magnetic tea biochar as a means to remove fluoride from water and ensure its suitability for drinking. Other studies conducted by Teng and Altaf [9,10] focused on the removal of highly persistent mercury from water to ensure safe drinking water and protect human health using eco-friendly techniques.…”