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The deposition rate of colloidal pitch onto hydrophobic and hydrophilic model surfaces was measured at the solid–liquid interface by impinging jet microscopy (IJM) and the effect of cation specificity in solution on deposition was quantified. On both model surfaces, the pitch deposition was slightly faster with calcium ions than with magnesium at the same concentration (800 mg/L). This concentration is around twice the critica coagulation concentration. The rate of colloidal pitch deposition on hydrophobic surfaces was far greater (up to a 2.5 times) than on hydrophilic surfaces for both salts. Contact angle measurements inferred that in the air-surface environment,the hydrophobicity of the surface does not affect its affinity for pitch suggesting molecular mobility within the pitch colloid. IJM shows variation in the pitch shape on the model surfaces. On hydrophilic surfaces, the pitch particle size for both salts ranges from 0.33 to 0.35 m while for hydrophobic surfaces the particle size is 5 times higher for calcium salt than for magnesium salt. Film thinning or spreading of the pitch particles occurred on the hydrophobic surfaces with calcium and to a lesser extent with magnesium salt.

Item Type:	Refereed Article
Keywords:	pitch, impinging jet, liquid solid interface, hydrophilic, hydrophobic, deposition, soft colloid, surface, cation
Research Division:	Chemical Sciences
Research Group:	Other Chemical Sciences
Research Field:	Industrial Chemistry
Objective Division:	Manufacturing
Objective Group:	Wood, Wood Products and Paper
Objective Field:	Pulp and Paper
Author:	Lee, R (Mr Roland Lee)
Author:	Lewis, T (Dr Trevor Lewis)
Author:	Stack, K (Dr Karen Stack)
ID Code:	76636
Year Published:	2011
Web of Science® Times Cited:	7
Deposited By:	Chemistry
Deposited On:	2012-03-08
Last Modified:	2017-10-25
Downloads:	0