Efficient Removal of Fluoride Using Polypyrrole-Modified Biochar Derived from Slow Pyrolysis of Pomelo Peel: Sorption Capacity and Mechanism

Journal Article · Sun Apr 15 04:00:00 EDT 2018 · Journal of Polymers and the Environment

DOI:https://doi.org/10.1007/S10924-017-1061-Y· OSTI ID:22788183

Wang, Jianguo; Chen, Nan ^[1]; Li, Miao ^[2]; Feng, Chuanping ^[1]

---

1. China University of Geosciences (Beijing), School of Water Resources and Environment (China)
2. Tsinghua University, School of Environment (China)

In this study, a novel adsorbent was developed by loading polypyrrole (PPy) onto biochar (BC) prepared by slow pyrolysis of pomelo peel. This PPy-grafted BC mainly exhibited anion-exchange behavior, which dramatically increased fluoride adsorption capacity. The effects of various factors (adsorbent dosage, pyrrole concentration, initial solution pH, co-existing anions and temperature) on the fluoride adsorption were investigated. The adsorbent was characterized by scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and automatic titration methods. Results showed that the optimized adsorbent (BP-0.1) performed excellently at pH 2.8–10.0, and possessed positive charge at pH < 8.6. The adsorption isotherm data were fitted well by the Langmuir model and the maximum adsorption capacity was 18.52 mg/g at 25 ± 2 °C. The adsorption kinetics followed the pseudo-second-order model and adsorption equilibrium was achieved at 24 h. Although both HCO{sub 3}{sup −} and CO{sub 3}{sup 2−} had great influence on F{sup −} adsorption, there was no significant impact in the presence of Cl{sup −}, NO{sub 3}{sup −} and SO{sub 4}{sup 2−}. Real groundwater study showed that 2.5 g/L of BP-0.1 could effectively reduce F{sup −} from 10.0 to 1.4 mg/L at pH 5.0. Thermodynamic parameters confirmed the spontaneous and endothermic nature of the adsorption process. Effect of pH, XPS analysis and the change of amount between Cl{sup −} and F{sup −} in the adsorption process revealed that ion exchange and electrostatic attraction were involved in the adsorption process and ion exchange was the main adsorption mechanism.

• OSTI ID: 22788183
• Journal Information: Journal of Polymers and the Environment, Journal Name: Journal of Polymers and the Environment Journal Issue: 4 Vol. 26; ISSN 1566-2543
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
GRAFTS
ION EXCHANGE
SCANNING ELECTRON MICROSCOPY
X-RAY PHOTOELECTRON SPECTROSCOPY