Thermal degradation of lignin under two reaction regimes (pyrolysis in N(2) and oxidative pyrolysis in 4% O(2) in N(2)) has been investigated in a tubular, isothermal, flow-reactor over the temperature range 200-900 °C at a residence time of 0.2 s. Two experimental protocols were adopted: (1) Partial pyrolysis in which the same lignin sample was continuously pyrolyzed at each temperature and (2) conventional pyrolysis, in which new lignin samples were pyrolyzed at each pyrolysis temperature. The results identified common relationships between the two modes of experiments, as well as some differences. The majority of products from partial pyrolysis peaked between 300 and 500 °C, whereas for conventional pyrolysis reaction products peaked between 400 and 500 °C. The principal products were syringol (2,6-dimethoxy phenol), guaiacol (2-methoxy phenol), phenol, and catechol. Of the classes of compounds analyzed, the phenolic compounds were the most abundant, contributing over 40% of the total compounds detected. Benzene, styrene, and p-xylene were formed in significant amounts throughout the entire temperature range. Interestingly, six ringed polycyclic aromatic hydrocarbons were formed during partial pyrolysis. Oxidative pyrolysis did not result in large differences from pyrolysis; the main products still were syringol, guaiacol, phenol, the only significant difference being the product distribution peaked between 200 and 400 °C. For the first time, low temperature matrix isolation electron paramagnetic resonance was successfully interfaced with the pyrolysis reactor to elucidate the structures of the labile reaction intermediates. The EPR results suggested the presence of methoxyl, phenoxy, and substituted phenoxy radicals as precursors for formation of major products; syringol, guaiacol, phenols, and substituted phenols.

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Phenol and its derivatives (phenol, o-, m-, p-cresols, catechol, hydroquinone, methoxy substituted phenols, etc. referred to as phenolic compounds or phenols) are well-known toxicants that exist in the environment and affect both human and natural ecosystems. This study explores quantitatively the yields of phenolic compounds from the thermal degradation (pyrolysis and oxidative pyrolysis) of common tobacco biomass components (lignin, tyrosine, ethyl cellulose, sodium alginate, and laminarin) as well as some mixtures (lignin/tyrosine, ethyl cellulose/tyrosine and sodium alginate/tyrosine) considered important in high temperature cooking, tobacco smoking, and forest fires. Special attention has been given to binary mixtures including those containing tyrosine-pyrolysis of binary mixtures of tyrosine with lignin and ethyl cellulose results in significant reductions in the yields of majority phenols relative to those from the thermal degradation of tyrosine. These results imply that the significant reductions of phenol yields in mixtures are not only dependent upon the mass fractions of the components but also the synergetic inhibition effect of biomass components on the thermal degradation of tyrosine. A mechanistic description of this phenomenon is suggested. The results may also be implied in tobacco industry that the cigarette paper (as ethyl cellulose derivative) may play a critical role in reducing the concentration of phenolic compounds released during tobacco burning.

The monitoring of water quality for both domestic and commercial use is absolutely essential for policy formulation that affects both public and environmental health. This study investigates the quality of water of river Molo system which lies in the Kenyan Rift Valley. The river is considered a vital source of water for the residents and industrial activities in Nakuru and Baringo Counties. Six water samples were collected during the dry season of December 2017. Various physicochemical parameters were determined in situ by use of a portable pH meter. These parameters included pH, temperature, electrical conductivity and total dissolved solids (TDS). Anions such as fluorides, sulfates, phosphates, nitrates, chlorides, carbonates and bicarbonates were determined using conventional methods such as titrimetry and (ultra-violet visible) UV-Vis techniques. The cations including sodium, potassium, calcium and magnesium were determined using flame photometry. The results showed that the water had pH values ranging from 7.90 to 9.66 units, temperature ranged from 14.02 to 31.5 °C, while electrical conductivity ranged from 181 to 1637 μS/cm, TDS (69-823 mg/L), F (2.76-3.28 mg/L), sulfates (4.97-85.66 mg/L), phosphates (0.13-11.06 mg/L), nitrates (1.73-6.16 mg/L), chlorides (38.5-69.4 mg/L), carbonates (18-148 mg/L), bicarbonates (54-384 mg/L), sodium (19-1800 mg/L), potassium (8.9-121 mg/L), magnesium (4.8-106.8 mg/L) and calcium (13.4-77.4 mg/L). The pH, temperature, fluorides and sodium were above the World Health Organization permissible limits for drinking water in S4 and S5. All the water samples fall under bicarbonate or freshwater zone. The sampling points can be classified into five water types: Na-Mg-Ca-HCO 3 , Na-HCO 3 , Na-Ca-Mg-HCO 3-CO 3 , Na and Na-Ca-HCO 3-CO 3. Chemical indices such as sodium adsorption ratio, magnesium hazard, percent sodium and permeability index are reported. Accordingly, the findings from this work indicate that the river Molo water in general is good for irrigation.