7 research outputs found
Sulfur Transformation during Microwave and Conventional Pyrolysis of Sewage Sludge
The
sulfur distributions and evolution of sulfur-containing compounds
in the char, tar and gas fractions were investigated during the microwave
and conventional pyrolysis of sewage sludge. Increased accumulation
of sulfur in the char and less production of H<sub>2</sub>S were obtained
from microwave pyrolysis at higher temperatures (500–800 °C).
Three similar conversion pathways were identified for the formation
of H<sub>2</sub>S during microwave and conventional pyrolysis. The
cracking of unstable mercaptan structure in the sludge contributed
to the release of H<sub>2</sub>S below 300 °C. The decomposition
of aliphatic-S compounds in the tars led to the formation of H<sub>2</sub>S (300–500 °C). The thermal decomposition of aromatic-S
compounds in the tars generated H<sub>2</sub>S from 500 to 800 °C.
However, the secondary decomposition of thiophene-S compounds took
place only in conventional pyrolysis above 700 °C. Comparing
the H<sub>2</sub>S contributions from microwave and conventional pyrolysis,
the significant increase of H<sub>2</sub>S yields in conventional
pyrolysis was mainly attributed to the decomposition of aromatic-S
(increasing by 10.4%) and thiophene-S compounds (11.3%). Further investigation
on the inhibition mechanism of H<sub>2</sub>S formation during microwave
pyrolysis confirmed that, with the special heating characteristics
and relative shorter residence time, microwave pyrolysis promoted
the retention of H<sub>2</sub>S on CaO and inhibited the secondary
cracking of thiophene-S compounds at higher temperatures
Paired-wise comparison of FA values in different ROIs.
<p>ROI were defined based on the activated clusters of ANCOVA (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0170185#pone.0170185.t001" target="_blank">Table 1</a>). * represents <i>p</i><0.05; ** represents <i>p</i> < 0.001.</p
Demographic characteristics of the three groups of participants including NC, aMCI-s and aMCI-m.
<p>Demographic characteristics of the three groups of participants including NC, aMCI-s and aMCI-m.</p
Regions showing significant FA differences among NC, aMCI-s and aMCI-m based on ANCOVA.
<p>The threshold was set at a TFCE-corrected P-value of less than 0.01 and a minimum cluster size of 50 contiguous voxels. Left is the left.</p
Regions showing significant FA differences among NC, aMCI-s and aMCI-m based on ANCOVA.
<p>The clusters with a TFCE-corrected P-value of less than 0.01 and a minimum cluster size of 50 contiguous voxels were reported.</p
Significant correlations between FA values and TMT scales were found to be negative in Lt. ATR, and positive in Lt. SLF and Lt. ILF. TMT: the trail making test.
<p>Significant correlations between FA values and TMT scales were found to be negative in Lt. ATR, and positive in Lt. SLF and Lt. ILF. TMT: the trail making test.</p
Significant correlations between FA values and BNT measures were found to be negative in Lt. UF, Lt. SLF and Lt. ILF, and positive in Lt. ATR. BNT: the Boston naming test.
<p>Significant correlations between FA values and BNT measures were found to be negative in Lt. UF, Lt. SLF and Lt. ILF, and positive in Lt. ATR. BNT: the Boston naming test.</p