Characterization of organic particulates present in milk factory process waters used for reuse along with aerobically digested effluent wastewater
- Authors: Verheyen, Vincent , Cruickshank, Alicia , Wild, Karl , Heaven, M. , McGee, R. , Watkins, Mark , Nash, David
- Date: 2010
- Type: Text , Journal article
- Relation: Bioresource Technology Vol. 102, no. 2 (2010), p. 2118-2125
- Full Text: false
- Reviewed:
- Description: Wastewater from a dairy processor is being reused and recycled both within the plant and for irrigation. Flash pyrolysis GC–MS was used to examine nitrogen and phenol containing compounds (M.W. = 35 to 450 g/mol) in the particulate fraction of the milk condensate, combined clean wastewater and aerobic bioreactor effluent. For comparison, the particulates were also prepared for standard GC–MS analyses using conventional solvent extraction methods. Compounds detected by pyrolysis GC–MS were found mostly in the bioreactor with the amino acid arginine (220 mg/kg) and the amino acid derivative 1-methyl-5-oxo-L-proline methyl ester (130 mg/kg) found at the highest concentrations. In comparison, sterols detected in the effluent were found at higher concentrations when using solvent extraction indicating some degradation with pyrolysis GC–MS. However, with few exceptions, particulates were generally found not to act as passive collectors capable of concentrating less water soluble chemicals.
Structural elucidation of humic acids extracted from Pakistani lignite using spectroscopic and thermal degradative techniques
- Authors: Nasir, Saqib , Sarfaraz, Tahira , Verheyen, Vincent , Chaffee, Alan
- Date: 2011
- Type: Text , Journal article
- Relation: Fuel Processing Technology Vol. 92, no. 5 (2011/05/01/ 2011), p. 983-991
- Full Text: false
- Reviewed:
- Description: The present paper describes the characterization of Pakistan lignite coal, derived humic acids (HAL) and nitrohumic acids (NHA) along with the standard leonardite humic acids (LHA). The study utilized chromatographic and spectroscopic techniques to characterize the structure of coal and derived materials. Pyrolysis coupled to gc/ms was conducted with and without methylating agent (tetramethyl ammonium hydroxide). The pyrolysis study resulted in releasing mainly fatty acid methyl esters, different series of hydrocarbons and α, ω-dicarboxylic acid methyl esters. Triterpenoids, syringic and ρ-coumaric compounds and aromatic compounds derived from lignin moieties were also detected. Fourier transform infrared (FT-IR) and NMR data helped to evaluate the influence of coal rank on regeneration and nitration processes with respect to chemical structural composition of coal and derived materials. FT-IR spectra of four materials were similar except that NHA showed an absorption band at 1532cm−1, thus confirming the presence of -NO2 groups. 13C NMR indicated higher aromaticity and less hydroxylalkyl material in HAL than NHA. The elemental composition and acid functional group content of four materials were also reported. The combination of results from different analytical techniques gives an improved understanding of the Pakistan coal nature and helpful for its future utilization.
Characterization of organic compounds in biochars derived from municipal solid waste
- Authors: Taherymoosavi, Sarasadat , Verheyen, Vincent , Munroe, Paul , Joseph, Stephen , Reynolds, Alicia
- Date: 2017
- Type: Text , Journal article
- Relation: Waste Management Vol. 67, no. (2017), p. 131-142
- Full Text: false
- Reviewed:
- Description: Municipal solid waste (MSW) generation has been growing in many countries, which has led to numerous environmental problems. Converting MSW into a valuable biochar-based by-product can manage waste and, possibly, improve soil fertility, depending on the soil properties. In this study, MSW-based biochars, collected from domestic waste materials and kerbsides in two Sydney's regions, were composted and pyrolysed at 450 °C, 550 °C and 650 °C. The characteristics of the organic components and their interactions with mineral phases were investigated using a range of analytical techniques, with special attention given to polycyclic aromatic hydrocarbons and heavy metal concentrations. The MSW biochar prepared at 450 °C contained the most complex organic compounds. The highest concentration of fixed C, indicating the stability of biochar, was detected in the high-temperature-biochar. Microscopic analysis showed development of pores and migration of mineral phases, mainly Ca/P/O-rich phases, into the micro-pores and Si/Al/O-rich phases on the surface of the biochar in the MSW biochar produced at 550 °C. Amalgamation of organic phases with mineral compounds was observed, at higher pyrolysis temperatures, indicating chemical reactions between these two phases at 650 °C. XPS analysis showed the main changes occurred in C and N bonds. During heat treatment, N-C/C=N functionalities decomposed and oxidized N configurations, mainly pyridine-N-oxide groups, were formed. The majority of the dissolved organic carbon fraction in both MSW biochar produced at 450 °C and 550 °C was in the form of building blocks, whereas LMW acids was the main fraction in high-temperature-biochar (59.9%). © 2017 Elsevier Ltd