Mingrui Zhang,Chao Tang,Hui Liu,Shufa Qin,Jie Liu,Mǎdǎlina Georgiana Albu Kaya,Keyong Tang
Tanneries are increasingly focusing on environmentally friendly processes, emphasizing the concept of clean production to minimize the environmental impact. This study investigated the eco-friendly application of an α-amylase/neutral protease system (ANS) in a single-step process for unhairing, fiber opening, and bating, providing an effective alternative to the conventional complex chemical-based lime-sulfide system (LSS). A mathematical model was established using response surface methodology (RSM) to optimize the operational conditions, yielding a 0.3 wt% α-amylase/0.5 wt% neutral protease solution at 28.4 °C for 16.6 h. The effects on unhairing and fiber opening were evaluated using scanning electron microscopy (SEM), while the effect on bating was accessed by the removal of carbohydrates and proteoglycans. The obtained leathers had comparable physical properties to their conventional counterparts, with enhanced hydrothermal shrinkage temperature and softness. In terms of environmental benefits, the optimized ANS could significantly decrease more than 90% of the chemical oxygen demand (COD), NH3–N, and Cl−, respectively, along with a 73.91% reduction in total solids (TS). Cost analysis indicated direct savings with a significant cost reduction of 30.98% of the ANS compared to that of the LSS, as well as additional indirect cost reduction through improved production efficiency and streamlined wastewater treatment processes. The use of electricity and water was reduced by 44.6% and 93.9%, respectively, which could reduce greenhouse gas emissions by 44.6%. This study highlighted the potential of α-amylase/neutral protease as a sustainable and cost-effective alternative in leather manufacturing that aligns with environmentally friendly practices.
Sining Yun,Tian Xing,Feng Han,Jing Shi,Ziqi Wang,Qingyang Fan,Hongfei Xu
Transition metal compounds have been widely used to enhance the anaerobic digestion (AD) performance, while the role of transition metal compounds in enhancing AD performance remains unclarified. In this work, the function of transition metal oxide accelerants (tantalum oxide, niobium oxide, hafnium oxide, and tungsten oxide) in enhanced AD systems was investigated from experimental and theoretical standpoints. Higher biogas production (565.01–617.85 mL/g VS), chemical oxygen demand degradation rate (67.17%-70.45%), total solids and volatile solids reduction rates (29.76%-34.71%, 51.83%-60.88%) were achieved in AD systems with transition metal oxide accelerants than the control (327.08 mL/g VS, 56.65%, 22.65%, and 41.18%). The first-principle density functional theory calculations, electron exchange capacity analysis, and the 16S rRNA gene pyrosequencing demonstrated superior electron transfer and exchange capacities as well as microbial consortia development in transition metal oxides-induced DIET mechanism. This work provides a promising strategy for understanding the function of high-performance accelerants in AD systems.
危险品化学品经营许可证（带存储）