Format

Send to

Choose Destination
ACS Appl Mater Interfaces. 2020 Feb 11. doi: 10.1021/acsami.9b20924. [Epub ahead of print]

Biochar Adsorbents with Enhanced Hydrophobicity for Oil Spill Removal.

Author information

1
Department of Chemistry , Mississippi State University , Mississippi State , Mississippi 39762 , United States.
2
Department of Chemistry , University of Louisville , Louisville , Kentucky 40292 , United States.
3
Department of Sustainable Bioproducts , Mississippi State University , Box 9820, Mississippi State , Mississippi 39762 , United States.
4
Material Science Lab, Integrated Microscopy Center , University of Memphis , Memphis , Tennessee 38152 , United States.
5
School of Environmental Sciences , Jawaharlal Nehru University , New Delhi 110067 , India.

Abstract

Oil spills cause massive loss of aquatic life. Oil spill cleanup can be very expensive, have secondary environmental impacts, or be difficult to implement. This study employed five different adsorbents: (1) commercially available byproduct Douglas fir biochar (BC) (SA ∼ 695 m2/g, pore volume ∼ 0.26 cm3/g, and pore diameter ∼ 13-19.5 Å); (2) BC modified with lauric acid (LBC); (3) iron oxide-modified biochar (MBC); (4) LBC modified with iron oxide (LMBC); and (5) MBC modified with lauric acid (MLBC) for oil recovery. Transmission, engine, machine, and crude oils were used to simulate oil spills and perform adsorption experiments. All five adsorbents adsorbed large quantities of each oil in fresh and simulated seawater with only a slight pH dependence, fast kinetics (sorptive equilibrium reached before 15 min), and high regression fits to the pseudo-second-order kinetic model. The Sips isotherm model oil sorption capacities for these sorbents were in the range ∼3-11 g oil/1 g adsorbent. Lauric acid-decorated (60-2 wt %) biochars gave higher oil adsorption capacities than the undecorated biochar. Lauric acid enhances biochar hydrophobicity and its water contact angle and reduces water influx into biochar's porosity preventing it from sinking in water for 3 weeks. These features were observed even at 2% wt of lauric acid (sinks only after 2 weeks). Magnetization by magnetite nanoparticle deposition onto BC and LBC allows the recovery of the exhausted adsorbent by a magnetic field as an alternative to filtration. Oil sorption was endothermic. Recycling was demonstrated after toluene stripping. The oil-laden adsorbents' heating values were obtained, suggesting an alternative use of these spent adsorbents as a low-cost fuel after recovery, avoiding waste disposal costs. The initial and oil-laden adsorbents were characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer-Emmet-Teller surface area, contact angle, thermogravimetric analyses, differential scanning calorimetry, vibrating sample magnetometry, elemental analysis, and X-ray photoelectron spectroscopy.

KEYWORDS:

adsorption; biochar; lauric acid; magnetite; oil spill

PMID:
31990524
DOI:
10.1021/acsami.9b20924

Supplemental Content

Full text links

Icon for American Chemical Society
Loading ...
Support Center