TY - JOUR
T1 - Inhibition of silica scaling with functional polymers
T2 - Role of ionic strength, divalent ions, and temperature
AU - Kaneda, Masashi
AU - Cao, Tianchi
AU - Dong, Dengpan
AU - Zhang, Xiaowei
AU - Chen, Yinan
AU - Zhang, Junwei
AU - Bryantsev, Vyacheslav S.
AU - Zhong, Mingjiang
AU - Elimelech, Menachem
N1 - Publisher Copyright:
© 2024 Elsevier Ltd
PY - 2024/7/1
Y1 - 2024/7/1
N2 - High concentrations of dissolved silica in saline industrial wastewaters and brines cause silica scale formation, significantly hampering the efficacy of diverse engineered systems. Applying functional polymers as scale inhibitors in process feedwater is a common strategy to mitigate silica scaling. However, feedwater characteristics often vary widely, depending on the specific processes, making the inhibition of silica scaling challenging and complex. In this study, we systematically investigate the role of ionic composition, specifically ionic strength and divalent ions, and solution temperature, in inhibiting silica scaling using molecularly designed amine/amide polymers. The inhibitor demonstrates effective stabilization of silicic acid, with inhibition efficiency of 74 and 55 % in the absence and presence of 20,000 ppm NaCl, respectively. However, further increasing the ionic strength of oversaturated silicic acid solutions significantly diminishes inhibition performance, rendering it ineffective at 180,000 ppm NaCl. Divalent inorganic cations exhibit a stronger impact on reducing inhibition efficiency compared to sodium ions. Molecular dynamics simulations reveal a competition mechanism between anionic silicic acid reactants (i.e., H3SiO4−) and chlorides for binding to ammonium groups within the polymeric inhibitor. Additionally, cations form clusters with H3SiO4− ions, hindering their stabilization with polymeric inhibitor. Notably, at elevated temperatures, the inhibitor achieves near-perfect inhibition for 500 ppm silicic acid solutions. This comprehensive assessment provides important insights into the effectiveness of silica scaling inhibitors under solution conditions relevant to real-world applications, addressing the challenges posed by varying solution parameters in diverse industrial processes.
AB - High concentrations of dissolved silica in saline industrial wastewaters and brines cause silica scale formation, significantly hampering the efficacy of diverse engineered systems. Applying functional polymers as scale inhibitors in process feedwater is a common strategy to mitigate silica scaling. However, feedwater characteristics often vary widely, depending on the specific processes, making the inhibition of silica scaling challenging and complex. In this study, we systematically investigate the role of ionic composition, specifically ionic strength and divalent ions, and solution temperature, in inhibiting silica scaling using molecularly designed amine/amide polymers. The inhibitor demonstrates effective stabilization of silicic acid, with inhibition efficiency of 74 and 55 % in the absence and presence of 20,000 ppm NaCl, respectively. However, further increasing the ionic strength of oversaturated silicic acid solutions significantly diminishes inhibition performance, rendering it ineffective at 180,000 ppm NaCl. Divalent inorganic cations exhibit a stronger impact on reducing inhibition efficiency compared to sodium ions. Molecular dynamics simulations reveal a competition mechanism between anionic silicic acid reactants (i.e., H3SiO4−) and chlorides for binding to ammonium groups within the polymeric inhibitor. Additionally, cations form clusters with H3SiO4− ions, hindering their stabilization with polymeric inhibitor. Notably, at elevated temperatures, the inhibitor achieves near-perfect inhibition for 500 ppm silicic acid solutions. This comprehensive assessment provides important insights into the effectiveness of silica scaling inhibitors under solution conditions relevant to real-world applications, addressing the challenges posed by varying solution parameters in diverse industrial processes.
KW - Antiscalants
KW - Inhibitors
KW - Molecular dynamics
KW - Polymers
KW - Silica polymerization
KW - Silicic acid
UR - http://www.scopus.com/inward/record.url?scp=85193573202&partnerID=8YFLogxK
U2 - 10.1016/j.watres.2024.121705
DO - 10.1016/j.watres.2024.121705
M3 - Article
AN - SCOPUS:85193573202
SN - 0043-1354
VL - 258
JO - Water Research
JF - Water Research
M1 - 121705
ER -