Rice huskwasobtainedfromaricemillinKelantan,
Malaysia.Phosphoricacid(85%),hydrochloricacid(37%)
and absoluteethanol(99.5%)werepurchasedfromSigma-
Aldrich. Sodiumhydroxide(99%)waspurchasedfrom
Merck inpelletform.AllchemicalsusedwereARgrades,
and distilledwaterwasusedforallsynthesisandtreatment
processes.