Zhenyu Wang,Zhu Tu,Lulu Lu,Zefeng Wang,Minghua Yang
The addition of the surfactant can greatly reduce the moisture content of the sludge. But little research has been done on the synthesis of surfactants and the mechanism of dehydration. Thus, a novel cationic surfactant ZWY-28 with higher surface activity and more surface charge was investigating for sludge dewatering in this research. Results showed that when the content of ZWY-28 was 1% (0.14 g/L), the specific resistance to the filtration of sludge had a minimum value of 2.04 × 10 12 m/kg, the moisture content of the dehydrated sludge cake reached a minimum of 78.9%, the bound water reduced to 6.32 g/g, decreased by 39.2%. What’s more, the ZWY-28 is extremely helpful in releasing Extracellular polymers substances from sludge, lead to the removal of bound water, which is the key point of affecting sludge dewatering. The study clearly illustrated that the surfactant ZWY-28 accelerated the dewatering process and could be used as a potential agent for sludge. Meanwhile, it provides ideas for the selection and structure design of surfactants in sludge dewatering.
Min Guan,Xingye An,Hao Zhang,Guihua Yang,Zhongjian Tian,Shuangxi Nie,Liqin Liu,Zhengbai Cheng,Haibing Cao,Hongbin Liu
Global liquid packaging industry has been greatly spurred by the rapidly growing food & beverage industry all over the world. Liquid packaging board (LPB), as the main composition (75–80 %) of laminated liquid packaging cartons, must possess high-quality of hydrophobicity and physical properties for excellent leak-proof and protecting the packaged commodity. Herein, in this study, lignin is selected to prepare lignin cationic surfactant (LCS) by quaternary ammonium modification. Then cationic lignin modified rosin size ( L -CDRS) with uniform microsphere structure and high colloidal stability is successfully synthesized via a phase inversion process to improve the sizing performance and mechanical properties of LPB. The cation modified LCS presents improved amphipathicity of rich cationic charges and hydrophobic benzene ring skeleton, thus enhancing the electrostatic interactions between LCS and pulp fibers and improving the sizing performance of L -CDRS. The sizing performance of LPB is evaluated by varying the LCS dosages within L -CDRS and concluded that the edge penetration value and Cobb value of LPB handsheets exhibit an improved size performance with 2 % LCS within L -CDRS, implying the formation of homogeneous hydrophobic surface layer induced by the well-distribution of L -CDRS. In addition, the tensile index of LPB increased from 19.74 N·m/g to 25.96 N·m/g assisted by 2 % LCS emulsified L -CDRS, indicating an improved mechanical property. This study puts forward a practical and facile strategy to improve the sizing performance and mechanical properties facilitated by lignin enhanced rosin size and will further broaden the application range of traditional rosin size and lignin in LPB products.
Xiao-Qian Wei,Wan-Ju Zhang,Lu Lai,Ping Mei,Li-Mei Wu,Yan-Qun Wang
The effects of cationic surfactants on the properties of Pickering emulsions stabilized by silica nanoparticles (nano-SiO 2 ) were investigated. The zeta potential , three-phase contact angle ( θ ), and dynamic interfacial tension (DIT) were measured to analyze the interaction between hydrophilic nano-SiO 2 and four different cationic surfactants (i.e., dodecyltrimethylammonium bromide [DTAB], bis-quaternary ammonium salts [BQAS-12], multiple quaternary ammonium salts [MQAS-12], and dimethyldioctadecylammonium bromide [DDAB-18]). All these surfactants can naturally improve the stability of Pickering emulsions induced by hydrophilic nano-SiO 2 . The nano-SiO 2 /MQAS-12 mixtures exhibited the best ability to stabilize the O/W emulsions, followed by nano-SiO 2 /BQAS-12 mixtures. The nano-SiO 2 /DDAB-18 mixtures can induce emulsion inversion from O/W to W/O. All emulsions exhibited excellent salt tolerance and acid-base resistance properties. Determining the zeta potential showed that nano-SiO 2 had the highest negative charge at the pH of 9.5. Thus, the surfactant molecules can be adsorbed remarkably on the nano-SiO 2 surface. Modification with different cationic surfactants can significantly increase the θ value of nano-SiO 2 , but the bilayers for DTAB-12, BQAS-12, and MQAS-12, except for DDAB-18, were adsorbed. DIT curves indicated that competitive adsorption of the surfactants occurred between the oil/water interface and nano-SiO 2 surface. The competitive adsorption of MQAS-12 was stronger than those of BQAS-12 and DTAB-12. The nano-SiO 2 /DDAB-18 mixture had an apparent induction region and required a considerable amount of time to reach equilibrium. The modified nano-SiO 2 was also not adsorbed in the oil/water interface spontaneously, which may be due to the large size of particles compared with small surfactant molecules.
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