Nickel adsorption and desorption in an acric oxisol as a function of pH, ionic strength and incubation time

Abstract

Although nickel (Ni) has both important potential benefits and toxic effects in the environment, its behavior in tropical soils has not been well studied. Nickel adsorption-desorption in topsoil and subsoil samples of an acric Oxisol was studied at three pH values (from 3.0 to 8.0). Adsorption-desorption isotherms were elaborated from experiments with increasing Ni concentration (5 to 100 mg L ). The Ni adsorption in the topsoil samples was higher, due to its lower point of zero salt effect (PZSE) and higher organic matter content. The increase in soil pH resulted in the increase of Ni adsorption. Nickel desorbed less from soil samples incubated for 4 or 12 weeks, suggesting that Ni interactions with colloidal particles increase over time. The amount of Ni desorbed increased with increasing ionic strength in both the topsoil and subsoil soil samples. Finally, adsorptiondesorption hysteresis was clearly observed. Soil pH, ionic strength of soil solution and the Ni-soil contact time should be considered as criteria for selecting the areas for disposal of residues containing Ni or to compose remediation strategies for acric soils contaminated with Ni.Index terms: Sorption; bioavailability; soil pollution; heavy metal. ). A adsorção de Ni foi maior nas amostras superficiais, devido ao menor ponto de efeito salino nulo e ao maior tero de matéria orgânica. A elevação do pH do solo aumentou a adsorção de Ni. Houve menos dessorção de Ni das amostras de solo incubadas por 4 e 12 semanas, sugerindo que as interações entre o Ni e as partículas do solo aumentam ao longo do tempo. A quantidade de Ni dessorvido aumentou com o aumento da força iônica, independentemente da profundidade de amostragem do solo. Finalmente, a histerese da reação de adsorção-dessorção de Ni foi claramente observada. O pH do solo, a força iônica da solução e o tempo de contato do Ni com o solo devem ser considerados critérios para a seleção de áreas para a disposição de resíduos contendo Ni e para compor estratégias de remediação para solos ácricos contaminados por Ni. RESUMOTermos para indexação: Sorção; biodisponibilidade; poluição do solo; metal pesado.

Pengaruh Biochar Serbuk Kayu Durian Terhadap Karakteristik Tanah Sulfat Masam Dalam Mengurangi Emisi Gas Metana

“…Komposisi larutan tanah dapat berubah secara substansial selama penyimpananinkubasi tanah. Secara umum, kekuatan ion dari larutan tanah meningkat selama penyimpanan atau inkubasi tanah yang diairi (Mellis et al, 2017). Sayangnya, pemahaman yang baik tentang pengendalian faktor-faktor yang menyebabkan perubahan konsentrasi selama inkubasi tanah belum tercapai.…”