Condensation Behavior of Heavy Metals during Oxy-fuel Combustion: Deposition, Species Distribution, and Their Particle Characteristics

This study aimed to characterize the condensation behavior of two heavy metals, namely, Pb and Zn, during oxy-fuel combustion and to clarify and compare the differences in their behavior during oxy-fuel versus air-fired combustion. A lab-scale rotary quartz reactor with a multi-stage cooling zone was used to analyze the deposition content and species distribution of the condensed Pb and Zn vapors at different temperature ranges and/or points and to observe their particle characteristics in the simulated oxy-fuel flue gas (OFFG), air-fired flue gas (AFFG), oxy-fuel flue gas without steam (OFFGWS), and air-fired flue gas without steam (AFFGWS). The deposition content of the condensed Pb and Zn vapors in the AFFG was consistently higher than that of OFFG in the cooling zone from 800 to 100 °C. Moreover, the steam content had an obvious influence on the deposition content. The condensed Pb and Zn vapors were mostly deposited in the sulfates in OFFG at 600–300 °C, instead of in the chlorides in AFFG. The average diameter of particles that contain Pb and Zn increased as the temperature decreased, and their shape factor in both AFFG and AFFGWS was higher than that in OFFG and OFFGWS

Temperature and pH Responsive Hydrogels Using Methacrylated Lignosulfonate Cross-Linker: Synthesis, Characterization, and Properties

In this work, biobased hydrogels with temperature and pH responsive properties were prepared by copolymerizing <i>N</i>-isopropyl­acrylamide (NIPAM), itaconic acid (IA), and methacrylated lignosulfonate (MLS), where the multifunctional MLS served as a novel macro-cross-linker. The network structures of the lignosulfonate-NIPAM-IA hydrogels (LNIH) were characterized and confirmed by elemental analysis, Fourier transform infrared, and ¹³C nuclear magnetic resonance. The equilibrium swelling capacity of the LNIH hydrogel decreased from 31.6 to 19.1 g/g with MLS content increasing from 3.7 to 14.3%, suggesting a strong dependence of water absorption of the gel on MLS content. LNIH hydrogels showed temperature-sensitive behaviors with volume phase transition temperature (VPTT) around the body temperature, which was also influenced by MLS content. Moreover, all LNIH hydrogels exhibited pH sensitivity in the range of pH 3.0 to 9.1. Rheological study indicated that mechanical strength of the gel also increased with MLS content. The results from this study suggest that lignosulfonate derivative MLS is a potential feedstock serving both water-absorbing moiety and cross-linker for preparation of biobased smart hydrogels