Proton consumption and release of organic‐cabon, silicate, and sulfate by anion sorption on andosols

Abstract

S:Three anion (selenite, phosphate, and fluoride) sorption, and the concomitant release of silicate, sulphate, and organic matters from soils, and proton consumption with sorption were investigated using two andosols in Japan.The following sequence of sorption by the andosols was, fluoride (F) >> phosphate (P) > selenite (Se); concomitant proton consumption with sorption, F >> P > Se; organic matter released, P > Se > F; and sulfate released, P > Se >> F. There was quite a difference between an allophanic and a non-allophanic andosols in silicate released with anion sorption. Our results suggest that the fluoride sorption mechanism is different from the others and that surface sites with OH groups for inner-sphere complexes with selenite on soil particles which are restricted as compared to phosphate and fluoride.

Selenite adsorption by a variety of oxides

“…However, humic-metal associates could be potentially an important fraction to adsorb selenite ion (Frits and Hall, 1987). Certainly a metal part (Al or Fe) of the humic-metal associates reacted with selenite ion, resulting in release of humic substance into solution (Saeki and Matsumoto, 1993). But the humic portion of the associates would hardly adsorb selenite because the adsorption was accelerated by removal or decomposition of organic portion of the associates (Saeki unpublished data).…”

“…Two humic acids were used as a representative organic substance in soils for selenite adsorption Downloaded by [New York University] study. One of the humic acids was manufactured by Wako Chemicals and the other humic acid was extracted from a Humic Andosol described in detail in our previous report (Saeki and Matsumoto, 1993). Adsorption Studv: Solution of selenite was prepared from sodium selenite (Na2SeO3) with distilled water.…”

“…Soil has been treated as an unit of adsorbent for selenite in previous studies (Saeki and Matsumoto, 1992;Saeki and Matsumoto, 1993). However, soils are heterogeneous assemblies of solid materials: phyllosilicates, oxide, oxyhydroxide, hydroxide, and organic matter.…”

Efeito do flúor sobre o alumínio e o fósforo em um podzólico vermelho-amarelo e sua acumulação em algumas espécies vegetais

“…A afinidade de alguns ânions com a superficie de óxidos de Fe ou Al hidratados foi descrita por Parfitt (1980), como sendo a seguinte: fosfato> molibdato > fluoreto > sulfato > cloreto > nitrato. Por outro lado, Saeki & Matsumoto (1993), estudando andossolos no Japão, verificaram que a energia de ligação do p-(afinidade com o AI) superava a dos ânions fosfato e este a dos ânions selenito, sendo seu mecanismo de adsorção diferente dos outros ânions.…”

Interação fósforo-silício-flúor em materiais de solo oxídico e uso benéfico de subproduto da indústria de fertilizantes fosfatados na soja

“…Vários são os fatores que exercem influência na retenção de fósforo no solo sendo os mais expressivos a matéria orgânica (PAVINATO;ROSOLEM, 2008;GONÇALVES et al, 1985), a mineralogia, influenciando tanto pela sua quantidade como pela sua qualidade EBERHARDT et al, 2008;, o potencial hidrogeniônico (SILVA et al, 1997) e ânions competidores, como silicatos (CARVALHO et al, 2000) e fluoretos (SAEKI, MATSUMOTO, 1993;AMARAL, 1997) A matéria orgânica, através de seus grupamentos funcionais de superfície (carboxílico, -COOH; fenólicos; anel aromático-OH; alcoolícos, -CH2OH) favorece o desenvolvimento carga negativa nos solos, diminuindo a retenção de fosfato nos colóides minerais. Tal fato está relacionado ao baixo valor de pH, no qual o balanço líquido de carga da matéria orgânica (ponto de carga zero = PCZ) é zero, o qual ocorre em torno de 3 (PCZ ~ 3).…”