This study investigated the characteristics of biochars derived from the pyrolysis of rubberwood sawdust (RWS) and sewage sludge (SS) and their co-pyrolysis at mixing ratios of 50:50 and 75:25. Biochars were produced at 550 °C through slow pyrolysis in a moving bed reactor and then characterized. Results showed that the rubberwood sawdust biochar (RWSB) had high carbon content (86.70 wt%) and low oxygen content (7.89 wt%). By contrast, the sewage sludge biochar (SSB) had high ash content (65.61 wt%) and low carbon content (24.27 wt%). The blending of RWS with SS at the mentioned ratios helped enhance the gross and element contents of the biochar samples. The elemental analysis of the biochars was also reported in the form of atomic ratios (H/C and O/C). The functional groups of biochars were observed by Fourier-transform infrared spectroscopy (FTIR). X-ray fluorescence spectroscopy (XRF) revealed that the biochar from SS contained a high content of inorganic elements, such as Si, Ca, Fe, K, Mg, P, and Zn. The pH of the biochars ranged from 8.41 to 10.02. Brunauer, Emmett, and Teller (BET) and scanning electron microscopy (SEM) showed that RWSB had a lower surface area and larger pore diameter than the other biochars. The water holding capacity (WHC) and water releasing ability (WRA) of the biochars were in the range of 1.01–3.08 mL/g and 1.19–52.42 wt%, respectively. These results will be the guideline for further application and study of biochar from RWS, SS, and blended samples.

A piperazine (PZ)-promoted methyldiethanolamine (MDEA) solution for a carbon dioxide (CO2) removal process from the flue gas of a large-scale coal power plant has been simulated. An Aspen Plus® was used to perform the simulation process. Initially, the effects of MDEA/PZ concentration ratio and stripper pressure on the regeneration energy of CO2 capture process were investigated. The MDEA/PZ concentration ratio of 35/15 wt.% (35 wt. MDEA and 15 wt.% PZ) was selected as an appropriate concentration. The reboiler duty of 3.235 MJ/kg CO2 was obtained at 35/15 wt.% concentration ratio of MDEA/PZ. It was considered a reference or base case, and process modifications including rich vapor compression (RVC) process, cold solvent split (CSS), and the combination of both processes were investigated to check its effect on the energy requirement. A total equivalent work of 0.7 MJe/kg CO2 in the RVC and a reboiler duty of 2.78 MJ/kg CO2 was achieved in the CSS process. Similarly, the total equivalent work, reboiler duty, and condenser duty of 0.627 MJe/kg CO2, 2.44 MJ/kg CO2, and 0.33 MJ/kg CO2, respectively, were obtained in the combined process. The reboiler duty and the total equivalent work were reduced by about 24.6 and 16.2%, respectively, as compared to the reference case. The total energy cost saving was 1.79 M$/yr. Considering the additional equipment cost in the combined process, the total cost saving was 0.67 M$ per year.

Matrix metalloproteinases (MMPs) are a family of hydrolytic enzymes that play significant roles in development, morphogenesis, inflammation, and cancer invasion. Endometase (matrilysin 2 or MMP-26) is a putative early biomarker for human carcinomas. The effects of the ionic and nonionic detergents on catalytic activity of endometase were investigated. The hydrolytic activity of endometase was detergent concentration-dependent exhibiting a bell-shaped curve with its maximum activity near the critical micelle concentration (CMC) of nonionic detergents tested. The effect of Brij-35 on human gelatinase B (MMP-9), matirilysin (MMP-7), and membrane-type 1 MMP (MT1-MMP) was further explored. Their maximum catalysis was observed near the CMC of Brij-35 (~90 μM). Their IC 50 values were above the CMC. The inhibition mechanism of MMP-7, MMP-9, and MT1-MMP by Brij-35 was mixed-type as determined by Dixon's plot, however, that of endometase was non-competitive with a K i value of 240 μM. The catalytic activities of MMPs are influenced by detergents. Monomer of detergents may activate and stabilize MMPs to enhance catalysis, but micelle of detergents may sequester enzyme and block substrate binding site to impede catalysis. Under physiological conditions lipid or membrane microenvironment may regulate enzymatic activity. KeywordsMatrix metalloproteinases (MMPs); MMP-26; ionic and nonionic detergents; critical micelle concentration; enzyme kinetics; enzyme inhibition mechanisms; regulation of catalytic activity; peptide hydrolysis; inhibition constant; putative cancer biomarker; homology modeling; hydrophobic interaction; lipids and membrane microenvironment; detergent-enzyme interaction; detergent-substrate interaction

No abstract

No abstract