SciELO - Scientific Electronic Library Online

 
vol.32 issueUNICOMineralogical study of soils derived from Bauru sandstone and basic rocks in the north-western region of São Paulo stateEffect of correction prunning on yield of old Niagara Rosada vines author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand

Journal

Article

Indicators

Related links

Share


Bragantia

Print version ISSN 0006-8705On-line version ISSN 1678-4499

Bragantia vol.32 no.unico Campinas  1973

http://dx.doi.org/10.1590/S0006-87051973000100018 

Determinação do ponto de carga zero em solos

 

Determination of the zero point of charge in soils

 

 

Bernardo van Raij*

Seção de Pedologia, Instituto Agronômico

 

 


SINOPSE

São apresentados os fundamentos e dois métodos de determinação do ponto de carga zero (PCZ) em solos.
Por um dos métodos o PCZ foi determinado como sendo o pH do ponto de cruzamento de curvas de titulação dos solos em soluções de NaCl 1; 0.1; 0 01; c 0,001N. Pelo outro método o PCZ foi determinado por extrapolação ou interpolação da carga líquida dos solos, determinada por retenção de íons em soluções de NaCl 0,2N, CaCl2 0,01N e MgSO4 0,01N, ao valor de pH em que a carga líquida era nula.


SUMMARY

The zero point of charge (ZPC) of soils was determined by the crossing point of acid-base potenciometric titration curves in different concentrations of NaCl. Alternatively, the ZPC was found by extrapolating or interpolating the net electric charge of soils, determined by direct adsorption of ions from solution of NaCl, CaCl2 and MgSO4, to the pH of charge zero.


 

 

Texto completo disponível apenas em PDF.

Full text available only in PDF format.

 

 

LITERATURA CITADA

1. ATKINSON, R. J.; POSNER, A. M. & QUIRK, J. P. Adsorption of potencial-determining ions at the ferric oxide-aqueous electrolyte interface. J. phys. Chem. 71:550-558, 1967.         [ Links ]

2. E.U.A. Soil Survey Staff. Soil taxonomy (selected chapters of the unedited text). Washington, U.S.D.A. Soil Conservation Service, 1970.         [ Links ]

3. FIELDES, M. & SCHOFIELD, R. K. Mechanisms of ion adsorption by inorganic soil colloids. J. Sci. 3:563-578, 1960.         [ Links ]

4. HARKINS, W. D. The physical chemistry of surface films. New York, Reinhold, 1952.         [ Links ]

5. KRUYT, H. R. Colloid science. Amsterdam, Elsevier, 1952. v.1.         [ Links ]

6. MATTSON, S. Anionic and cationic adsorption by soil colloidal materials of varying SiO2/Al2O3 + Fe203 ratio. In: Trans. Intern. Congress Soil Sci., 1., Washington, 1927. v.2, p. 199-211.         [ Links ]

7. PARKS, G. A. Aqueous surface chemistry of oxides and complex oxide minerals. Isoelectric point and zero point of charge. Adv. Chem. Ser. 67:121-160, 1927.         [ Links ]

8. ________. & DE BRUYN, P. L. The zero point of charge of oxides. J. phys. Chem. 66:967-973, 1962.         [ Links ]

9. PAULING, L. The nature of the chemical bond. 3.ed. Ithaca, Cornell University Press, 1960. 644p.         [ Links ]

10. RAIJ, B. van Determinação de cargas elétricas positivas e negativas em solos. Bragantia 31:171-183, 1972.         [ Links ]

11. ________. Electrochemical properties of some Brazilian soils. Ph. D. thesis. Cornell University, 1971. 144p.         [ Links ]

12. ________ & PEECH, M. Electrochemical properties of some Brazilian soils. Proc. Soil. Soc. Am. 36:587-593, 1972.         [ Links ]

13. SUMNER, M. E. & DAVIDTZ, J. C. Positive and negative charges in some Natal soils. Afr. J. agric. Sci. 8:1045-1050, 1965.         [ Links ]

14. VAN OLPHEN, H. Introduction to clay colloid chemistry. New York, Interscience, 1963. 301p.         [ Links ]

 

 

Recebido para publicação em 13 de agosto de 1973.

 

 

* Com bolsa de suplementação do CNPq.

Creative Commons License All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License