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Surface changes in an original and activated bentonite

1952; US government; Volume: 48; Issue: 4 Linguagem: Inglês

10.6028/jres.048.041

2376-5305

J. de D. López-González, Victor R. Deitz,

Soil and Unsaturated Flow

The p h ys ical adsorption of ni trogen was used to st ud y a bentoni te activated by a t reatm en t with h ydrochloric acid.The Brunauer-E mmett-Teller equation , t he Huttig equation , and a so-call ed "summation " eq uatio n were used in t he calculation of th e surface ar ea s available to ni trogen .Th e cha nges in surface area at different te mperat ures ha ve bee n related to t he q uan t ity of ad sor bed water and t he amount of con s ti t ut ional h ydro xyl grou ps.The surface area is a measure of on ly th e external boundary (nons welli ng surface) of th e bentonite, and this is in crea sed signifi cantly by t he activation pro cess.The ratio of surface areas (a ctivated to ori ginal) is about four.A max imum in t he s urface area was found tJ exist when a ll of t he adsorbed watel' was eliminated.However, t he surface area d ecreased wit h t he removal of water formed by d ecomposit ion of t he constitutional h ydroxyl gro ups.Chemical analyses, d eh ydrat ion curves, t hermal d iffere ntial analyses, X-ray patterns, and elec tron mi crographs were employed to cha racteri ze the materials.