chat gpt

Question 1

what is colloidal facilitated transport?

Answer 1

-affects movement and bioavailability of contaminants and nutrients
-acts as carriers for contaminants, which enhances their mobility
mechanisms:
-sorption (adsorption and incorporation)
-mobility enhancement (heavy metals and hydrophobic organic pollutants have low solubility, but then when attached to colloids, they remain suspended in water)
-decomposition and release (change in pH, ionic strength, or redox conditions can cause colloid aggregation, leading to decomposition and contaminant release into sediments. ex: acidification detoxes colloidal iron, releasing bound contaminants)

Question 2

what are the surface properties of colloids?

Answer 2

surface charge: often carry electrical charge
-clay (negative charge) attracts metal cations (Pb2+)
-iron oxide colloids (+ at low pH) absorb arsenic

functional groups: contain reactive groups (OH, COOH) enable adsorption, ion exchange and surface complexation