Dual activators can be used together or in sequence to intensify pore development in activation of biomass. If used in sequence, arrangement of an activator in first- and second-round activation dictates overall reaction network in activation and pore characteristics of activated carbon (AC). Herein, activation of willow wood with single, mixed ZnCl 2 and H 3 PO 4 , or activators in sequence (activation firstly with ZnCl 2 or H 3 PO 4 at 350 °C and the other activator subsequently at 550 °C) were conducted. The results showed that the H 3 PO 4 →ZnCl 2 sequential activation (activating first with H 3 PO 4 then with ZnCl 2 ) destructed P-O-C bonds and created additional micropores, forming H 3 PO 4 →ZnCl 2 -AC of 1344.7 m 2 /g with superior capability for adsorption of phenol from phosphorus doping. Nonetheless, The ZnCl 2 →H 3 PO 4 sequential activation did not enhance pore development (998.5 vs. 991.8 m 2 /g for H 3 PO 4 -AC) and reduced AC yield to 27.8 %, due to deficient aliphatics for second-round activation with H 3 PO 4 . Co-activation with ZnCl 2 +H 3 PO 4 only enhanced percentage of micropore but not S BET . Activation with ZnCl 2 but not H 3 PO 4 transformed fibers into densified bulky particles. However, activator selected in first-round activation determined final morphology of ACs in sequential activation.
Xiao Cheng,Yuchen Jiang,Kai Sun,Chao Li,Shu Zhang,Yi Wang,Hengda Han,Xun Hu
Mixing feedstocks of varied aromatic/aliphatic content is a simple method for tailoring pore structures of activated carbon (AC) in activation. Herein, willow wood and homogenous biochar produced at 300 or 500°C, which have distinct content of aliphatic component, were co-activated with K 2 C 2 O 4 , at 800°C for changing pore characteristics of resulting AC. The results indicated that co-activation of willow and biochar diminished production of AC and impacted evolution of organics and gases through intensive volatiles-char interactions. The AC from the co-activation of willow with either biochar-300 or biochar-500 exhibited higher specific surface area than that from direct activation of willow (1409.7 or 1297.0 m 2 g −1 versus 1243.6 m 2 g −1 ), which was also higher than calculated average of that from feedstock (ca. 1160 m 2 g −1 ). This resulted from intensified gasification of the biochar with H 2 O/CO 2 derived from willow, creating additional macropores and micropores of enlarged pore sizes. The enhanced gasification also reduced crystallinity of graphitic carbon, lowered O content via accelerated deoxygenation and diminished C O on nascent AC. Volatiles-char interactions also minimized pore filling from carbonaceous deposit generated from secondary condensation of primary volatiles. Additionally, direct activation of aliphatic-rich willow tended to form more micropores, while more mesopores were formed from aromatic-rich biochar.
Liu Xiaokai,Li Xilin,Zhao Baiyun,Zhou Lijuan,Wang Li
Salix is an abundant renewable resource with wide sources and low cost. Therefore, a magnetic fiber membrane adsorbent for removing tetracycline (TC) in water was prepared from Salix wood powder. The optimum preparation conditions were discussed, and the optimum initial TC concentration, pH value, adsorption temperature, and adsorption time were determined. In the meantime, the maximum adsorption amount reached 538.73 mg·g −1 . The adsorption process belongs to the multi-molecular layer adsorption with chemical adsorption as the main factor and physical adsorption as the auxiliary factor. The adsorption process is mediated by multiple mechanisms including intramolecular diffusion, electrostatic interaction, hydrogen bonding, and chemical ion exchange, and the adsorbent was easy to separate from water. The results show that the magnetic cellulose membrane is a promising adsorbent which deserves further study. Graphical Abstract
危险品化学品经营许可证（带存储）