Adsorbent properties of red mud and its use for wastewater treatment

López, Esperanza; Soto, B.; Arias, Manuel; Rodríguez‐Núñez, Eugenio; Rubinos, David A.; Barral, María Teresa

doi:10.1016/s0043-1354(97)00326-6

Cited by 308 publications

(123 citation statements)

References 13 publications

Supporting

Mentioning

111

Contrasting

Unclassified

Order By: Relevance

“…Ese problema medioambiental ha hecho que se hayan dedicado una importante cantidad de esfuerzos al estudio de aplicaciones para poner en valor estos residuos y darles así una salida [3][4][5] . En trabajos recientes propios [1, 2, 6 y 7] se demuestra la eficacia de ambos tipos de lodos como inhibidores de la corrosión del hierro y acero en disoluciones alcalinas cloruradas.…”

Section: I In Nt Tr Ro Od Du Uc Cc Ci Ió óN Nunclassified

Estudio comparativo del comportamiento electroquímico del hierro en medio alcalino en presencia de lodos rojos y lodos grises. Efecto del Al<sup>3+</sup>

et al. 2009

View full text Add to dashboard Cite

E Es st tu ud di io o c co om mp pa ar ra at ti iv vo o d de el l c co om mp po or r t ta am mi ie en nt to o e el le ec ct tr ro oq qu uí ím mi ic co o d de el l h hi ie er rr ro o e en n m me ed di io o a al lc ca al li in no o e en n p pr re es se en nc ci ia a d de e l lo od do os s r ro oj jo os s y y l lo od do os s g gr ri is se es s. . E Ef fe ec ct to o d de el l A Al l 3 3+ + ( ( • • ) ) C.M. Abreu * , L. Freire * , X.R. Nóvoa * , G. Pena * y M.C. Pérez * R Re es su um me en n Los elevados volúmenes de residuos generados por los lodos rojos (LR), procedentes del proceso de obtención de la alúmina a partir de la bauxita y los lodos grises (LG), originados durante el proceso de la transformación del granito, suponen un grave problema medioambiental. Trabajos recientes de este grupo demuestran la eficacia de ambos tipos de lodos como inhibidores de la corrosión del hierro y acero en medio alcalino clorurado. Esta característica ha llevado al estudio individualizado de sus componentes mayoritarios y, dentro de éstos, el Al 3+ , elemento común presente en mayor proporción. El estudio mediante técnicas electroquímicas como la Voltametría Cíclica (VC) y la Espectroscopía de Impedancia Electroquímica (EIE), apoyadas en técnicas de análisis químico y superficial, ha permitido visualizar cómo el Al 3+ es capaz de bloquear la superficie del acero en medio alcalino aumentando su resistencia al ataque por cloruros. P Pa al la ab br ra as s c cl la av ve eLodos rojos; Lodos grises; VC; EIE; Corrosión.C Co om mp pa ar ra at ti iv ve e s st tu ud dy y o of f t th he e e el le ec ct tr ro oc ch he em mi ic ca al l b be eh ha av vi io ou ur r o of f i ir ro on n i in n a al lk ka al li in ne e m me ed di ia a c co on nt ta ai in ni in ng g r re ed d m mu ud d a an nd d g gr re ey y s sl lu ur rr ri ie es s. . T Th he e e ef ff fe ec ct t o of f A Al l 3 3+ + A Ab bs st tr ra ac ct t Red mud (RM) is the main by-product of the Bayer process for alumina extraction from bauxite, and grey slurries (GS) are generated during the granite rocks transformation processes. The huge volume of those wastes generated every year suppose a serious environmental problem. Recent works by our group demonstrate the efficiency of both types of muds as corrosion inhibitors for iron and steel in alkaline media containing chlorides. The elemental analysis of these slurries shows that Al 3+ is the main common element. Therefore, the aim of this paper is to study the effect of the soluble Al 3+ in the electrochemical behaviour of iron in alkaline media, in presence and absence of chlorides. The electrochemical study using Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) together with surface analysis techniques allowed to conclude that Al 3+ blocks the surface of steel in alkaline media chloride increasing the steel resistance to chloride attack. K Ke ey yw wo or rd ds s I IN NT TR RO OD DU UC CC CI IÓ ÓN NLos lodos rojos (LR) y los lodos grises (LG) son los principales residuos resultantes de dos procesos industriales am...

show abstract

Section: I In Nt Tr Ro Od Du Uc Cc Ci Ió óN Nunclassified

Estudio comparativo del comportamiento electroquímico del hierro en medio alcalino en presencia de lodos rojos y lodos grises. Efecto del Al<sup>3+</sup>

et al. 2009

View full text Add to dashboard Cite

show abstract

“…However, activated carbon remains an expensive material since its high cost, which restricted its widespread use. In recent years, considerable attention has been paid based on economic and environmental concerns to the study of using different types of low-cost sorbents such as alum sludge [3], red mud (RM) [4][5][6], fly ash (FA) [7] and other waste materials [8,9] as alternative adsorbents for sorption of phosphate from water. Therefore, the sorbent with the best sorption capacity should be selected to satisfy both economic efficiency and convenience.…”

Section: Introductionmentioning

confidence: 99%

Phosphate removal from aqueous solutions using raw and activated red mud and fly ash

Liu

Luan

et al. 2006

Journal of Hazardous Materials

290

136

View full text Add to dashboard Cite

The effect of acidification and heat treatment of raw red mud (RM) and fly ash (FA) on the sorption of phosphate was studied in parallel experiments. The result shows that a higher efficiency of phosphate removal was acquired by the activated samples than by the raw ones. The sample prepared by using the RM stirred with 0.25 M HCl for 2 h (RM0.25), as well as another sample prepared by heating the RM at 700• C for 2 h (RM700), registered the maximum removal of phosphate (99% removal of phosphate). This occurred when they were used in the phosphate sorption studies conducted at pH 7.0 and 25• C with the initial PO 4 3− concentration of 155 mg P/l. The FA samples treated in the same way described above can achieve 7.0 and 8.2 mg P/l phosphate removal for FA0.25 and FA700 respectively, corresponding to 45.2% and 52.9% removal. The activated materials performed higher phosphate removal over broader pH range compared with the raw ones. The influences of various factors, such as initial pH and initial phosphate concentration on the sorption capacity were also studied in batch equilibration technique. Solution pH significantly influenced the sorption. Each sample achieved the maximal removal of phosphate at pH 7.0. The amount of phosphate removal increased with the solute concentration. The Freundlich and Langmuir models were used to simulate the sorption equilibrium. The results indicate that the Langmuir model has a better correlation with the experimental data than the Freundlich model.

show abstract

“…Adsorption is one of the techniques which would be comparatively useful and economical for phosphate removal. In recent years, considerable attention has been paid to low-cost adsorbents such as alum sludge (Galarneau and Gehr, 1997), red mud (Shiao and Akashi, 1977;López et al, 1998;Pradhan et al, 1998), fly ash (Oguz, 2005) and other waste materials (Agyei et al, 2000(Agyei et al, , 2002 as adsorbents for adsorption of phosphate from wastewater economically.…”

Section: Introductionmentioning

confidence: 99%