TY - JOUR
T1 - The influence of dairy salts on nanofiltration membrane charge
AU - Rice, Gwyneth
AU - Barber, Andrew
AU - O'Connor, Andrea
AU - Pihlajamaki, Arto
AU - Nystrom, Marianne
AU - Stevens, Geoff
AU - Kentish, Sandra
PY - 2011/12
Y1 - 2011/12
N2 - The nanofiltration of dairy ultrafiltration permeate can be used to produce a concentrated lactose product that is reduced in unwanted monovalent salts. In this paper, the surface charge of three nanofiltration membranes commonly used for such a purpose is examined. The focus is the impact of multivalent anions, notably phosphate and citrate, upon the surface charge of the membranes within a ternary system of potassium and calcium chloride. It was shown that these multivalent anions can influence the membrane charge through interactions with calcium, even though they are unlikely to adsorb to the membrane surface. Specifically, both phosphate and citrate can form soluble charged species with the calcium ions, reducing the net Ca2+ concentration and hence the overall effect of calcium on the membrane. This ion interaction effect becomes more dominant at higher pH values, due to the greater tendency of calcium to interact with either phosphate or citrate at higher pH.
AB - The nanofiltration of dairy ultrafiltration permeate can be used to produce a concentrated lactose product that is reduced in unwanted monovalent salts. In this paper, the surface charge of three nanofiltration membranes commonly used for such a purpose is examined. The focus is the impact of multivalent anions, notably phosphate and citrate, upon the surface charge of the membranes within a ternary system of potassium and calcium chloride. It was shown that these multivalent anions can influence the membrane charge through interactions with calcium, even though they are unlikely to adsorb to the membrane surface. Specifically, both phosphate and citrate can form soluble charged species with the calcium ions, reducing the net Ca2+ concentration and hence the overall effect of calcium on the membrane. This ion interaction effect becomes more dominant at higher pH values, due to the greater tendency of calcium to interact with either phosphate or citrate at higher pH.
KW - Citrate
KW - Dairy ultrafiltration permeate
KW - Nanofiltration
KW - Phosphate
KW - Zeta potential
UR - http://www.scopus.com/inward/record.url?scp=79961028469&partnerID=8YFLogxK
U2 - 10.1016/j.jfoodeng.2011.06.028
DO - 10.1016/j.jfoodeng.2011.06.028
M3 - Article
VL - 107
SP - 164
EP - 172
JO - JOURNAL OF FOOD ENGINEERING
JF - JOURNAL OF FOOD ENGINEERING
SN - 0260-8774
IS - 2
ER -