Rapid remediation of pharmaceuticals from wastewater using magnetic Fe3O4/Douglas fir biochar adsorbents. (November 2020)

• Record Type: Journal Article
• Authors: Liyanage, Achala S.; Canaday, Sydney; Pittman, Charles U.; Mlsna, Todd
• Is Part Of: Chemosphere. Volume 258(2020)
• Publication Date: 2020-11
• Subjects: Magnetic biochar -- Caffeine -- Ibuprofen -- Acetylsalicylic acid -- Iron oxide; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2020.127336
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Modification of commercially available Douglas fir biochar (BC) by iron oxide nanoparticle precipitation from aqueous Fe 2+ /Fe 3+ salt solutions upon NaOH treatment generated a hybrid adsorbent (MBC) that removed three common emerging aqueous contaminants, a stimulant (caffeine) and two anti-inflammatory drugs (ibuprofen and acetylsalicylic acid) through batch sorption. Fe3 O4 particles (12.3 ± 7.1 nm diameter fundamental particles with aggregates 1–17 μm diameter) dispersed on the biochar surface provided magnetization and created new adsorption sites for the contaminant uptake. These smaller quasi-spherical, octahedral Fe3 O4 particles as well as the spindle-like Fe2 O3 particles were observed with scanning electron microscopy (SEM) images of MBC, and the composition was confirmed by X-ray powder diffraction (XRD). Adsorption features were evaluated using Langmuir and Freundlich isotherm models. The Langmuir adsorption capacities on MBC at 35 °C have increased from 24.6 ± 0.4 to 75.1 ± 1.8 mg/g for caffeine, 17.5 ± 0.4 to 39.9 ± 1.2 mg/g for ibuprofen and 106.2 ± 2.8 to 149.9 ± 4.5 mg/g for acetylsalicylic acid after Fe3 O4 modification. Fast adsorption resulted in equilibrium within 5 min. MBC has potential as a low cost, green adsorbent for pharmaceutical mitigation from water with high adsorption capacities and fast kinetics. The Douglas fir biochar is a byproduct waste from a syn-gas from wood production process covering its production costs. Highlights: Biochar and magnetic Fe3 O4 hybrids had high pharmaceutical removal capacities. Adsorptive removal was fast (<5 min). Showed good reusability through five recycles. Fe3 O4 enhanced adsorption. Bound magnetic particles allow fast batch adsorption and avoid need to filter.