Microwave and open vessel digestion methods for biochar

Wathudura, Pathum; Peiris, Chathuri; Navarathna, Chanaka; Mlsna, Todd; Kaumal, M. N.; Vithanage, Meththika; Gunatilake, Sameera R.

doi:10.1016/j.chemosphere.2019.124788

Cited by 22 publications

(3 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Complete acid digestions were performed on 0.1 g of each adsorbent using 50.0 mL of 1:1 95% H 2 SO 4 /70% HNO 3 . 35 Iron dissolved from the oxidizing adsorbent samples goes into the acid over 24 h (70 °C) with stirring. These solutions were then diluted 10-fold with deionized water prior to AAS analysis.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Biochar Adsorbents with Enhanced Hydrophobicity for Oil Spill Removal

Navarathna

Dewage

Keeton

et al. 2020

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

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 m 2 /g, pore volume ∼ 0.26 cm 3 /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 lowcost 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.

show abstract

Section: Methodsmentioning

confidence: 99%

“…The weight percentages of iron in all adsorbents were determined using atomic absorption spectroscopy (AAS) (Shimadzu AA-7000). Complete acid digestions were performed on 0.1 g of each adsorbent using 50.0 mL of 1:1 95% H 2 SO 4 /70% HNO 3 . Iron dissolved from the oxidizing adsorbent samples goes into the acid over 24 h (70 °C) with stirring.…”

Section: Methodsmentioning

confidence: 99%

Biochar Adsorbents with Enhanced Hydrophobicity for Oil Spill Removal

Navarathna

Dewage

Keeton

et al. 2020

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

show abstract

“…This wet digestion method offers several advantages, including the capacity to use larger reagent volumes and reduced overall cost (Mohammed et al 2017). Despite the prevalent use of microwave digestion procedures in numerous studies involving biological samples (Zhong et al 2016;Wathudura et al 2020), which involves higher costs, literature has consistently reported on comparative studies aimed at achieving higher recovery percentages and reduced matrix effects through the application of open-vessel digestion compared to microwave-assisted digestion (Tüzen 2003;Mohammed et al 2017). The choice of acid combination is important in this aspect.…”

Section: Digestion Of Samplesmentioning

confidence: 99%

Analysis of the heavy metals and Escherichia coli contamination of liquid organic fertilizers in the local market, Sri Lanka

Yasara,

Dananjana,

Wijeratne

2024

Braz. J. Develop.

View full text Add to dashboard Cite

Commercially available liquid organic fertilizers have gained popularity in agriculture due to their convenience and perceived environmental benefits. However, these fertilizers are susceptible to various contaminations, including heavy metals such as lead (Pb) and cadmium (Cd), as well as bacterial contaminants like Escherichia coli (E. coli). Monitoring these contaminants helps to identify potential health risks to consumers, prevent soil and water pollution, and maintain the quality of agricultural products. Therefore, this study involved a comprehensive analysis of Pb and Cd heavy metals and E. coli bacterial contaminants in two widely used liquid organic fertilizers in the local market. The samples were digested using an open-vessel acid digestion followed by the flame atomic absorption spectroscopic (FAAS) analysis. The limit of detection (LOD), limit of quantification (LOQ), matrix effect, and spike recovery were determined. The Pb concentration of one fertilizer was 3.45 (± 0.07) mg/kg with 92% recovery whereas the other was 2.87 (± 0.08) mg/kg with 91% recovery. In contrast, the Cd concentration was 0.09 (± 0.01) mg/kg and 0.11 (± 0.01) mg/kg with percentage recoveries of 93% and 90% for two fertilizers respectively. The Pb content exceeded the maximum permissible limit of 1.0 mg/kg set by the Sri Lanka Standard (SLS 1702:2121), while Cd levels remained within the limit of 0.5 mg/kg. Polymerase chain reaction (PCR) coupled with gel electrophoresis confirmed the presence of the pathogenic O157:H7 E. coli strain in both fertilizers. Thus, the results of this study confirmed the lead (Pb) and Escherichia coli contamination in liquid organic fertilizers in the local market of Sri Lanka.

show abstract