Abstract
An attempt has been made to assess the involvement of the acidic functional groups of humic substances in the formation of clay-humus complexes. The humic substances used included four different samples of varying acid-group content as well as a series of methylated derivatives of one humic acid (HA). Amounts of soluble HA/FA (fulvic acid) retained by montmorillonite after repeated washing of the predried complexes with water were estimated. Results reveal a trend of decrease in fixation with increase in acidity of the humic samples. Methylation of the acidic groups has the same effect. It is proposed that a decreasing content of acidic groups in humic substances promotes their fixation by montmorillonite because of a lowering of interparticle repulsive forces as well as a reduction in hydration energies; the net energy available for breaking down the clay-humus bonds is consequently decreased. Nonionic attractive forces are important interactive modes in complexes that have been dried.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
