Problem $5\mathrm{.}6$

$5\mathrm{.}6$ You are a sales engineer working for a polymer supply company selling poly acrylic acid $($PAA$).$ PAA is a water soluble anionic $($negatively charged polymer$)$ that comes in different molecular weights: $10000,100000,1$ million and $10$ million. You have two

Figure $5$E$6\mathrm{.}1$ Adsorption isotherms for PAA of various molecular weights

customers. The first customer is using $0\mathrm{.}8m$ alumina to produce ceramics. This customer would like to reduce the viscosity of the suspension of $40$vol$\%$ solids suspensions. The second customer is trying to remove $0\mathrm{.}8m$ alumina from wastewater. There is about $2$ vol $\%$ alumina in the water and he wants to remove it by settling. What would you recommend to each customer? Consider if PAA is the right material to use, what molecular weight should be used and how much should be used. Figure $5$E$6\mathrm{.}1$ shows the adsorption isotherms for PAA with different molecular weights.