Competitive heavy metals adsorption on natural bed sediments of Jajrood River, Iran

Abstract

The presence of heavy metal concentrations was examined in natural sediments from four sites along the Jajrood river in northeast of Tehran, the capital of Iran. Besides determination of elemental concentrations (Pb, Cu, Zn, Cd, Ni and Cr), X-ray fluorescence and X-ray diffraction tests were carried out to determine other chemical components in these adsorbents. Also the ability of sediments to adsorb these heavy metal ions from aqueous solutions was investigated. Results show that the extent of adsorption increases with increase in adsorbent concentration. The amount of adsorbed Pb, Cu and Zn in sediments was much greater than that of the other metals, and Cr was adsorbed much less than others. The adsorbabilities of sediments to heavy metals increased in the order ofBased on the adsorption data, equilibrium isotherms were determined at selected areas to characterize the adsorption process. The adsorption data followed Freundlich and Langmuir isotherms in most cases. Correlation and cluster analysis was performed on heavy metals adsorption and sediment components at each site to evaluate main adsorbing compounds in sediments for each metal. Results demonstrated that heavy metals sorption is mostly related to load of organic matter in the Jajrood river sediments.

Assessment of heavy metals in sediment of Aguamilpa Dam, Mexico

“…When these contaminants are found in a waterbody, they often are absorbed by the suspended organic matter, and suspended particles containing associated contaminants can settle at the bottom and become part of the sediment, depending on the morphology of the water body and its hydrological characteristics (Saeedi et al 2011).…”

Simultaneous Adsorption of Cu (II), Zn (II) and Ni (II) on Clays from Solimões Formation

“…A afinidade de íons pelos sítios adsorventes pode ser preliminarmente avaliada com base na constante de afinidade K L de Langmuir, conforme demonstrado em vários estudos anteriores. [31][32]37 Avaliações mais eficientes sobre as afinidades de íons metálicos em minerais de argila, 3,4,10-12 solos [16][17] e sedimentos [21][22] e bioadsorventes, 13 são realizadas com base nas constantes de distribuição (K d ), correspondentes aos pontos iniciais dos processos de adsorção, onde há menor cobertura dos adsorvatos nos adsorventes. 15,16 A constante de distribuição (K d ) é considerada igual a constante de equilíbrio termodinâmica, calculada a partir da Equação 7.…”

“…14 A afinidade de adsorção é geralmente avaliada pelo coeficiente de distribuição, definido pela relação entre a quantidade adsorvida na fase sólida pela concentração de equilíbrio na fase líquida, [15][16] que é muito utilizado na avaliação da afinidade de processos de adsorção envolvendo competição entre íons metálicos por um adsorvente, [11][12][13] ou competição simultânea de íons metálicos por vários adsorventes, como ocorre naturalmente em solos ou sedimentos [17][18][19] e sedimentos. [20][21] Experimentos de adsorção competitiva simultânea de íons metálicos ou outras espécies químicas por diferentes minerais de argila, como caulinita 3,[11][12][13]22 e mica, 23 têm grande importância nos trabalhos envolvendo remediação de solos e seletividade de adsorventes adequados na retenção simultânea de diferentes espécies químicas. [16][17][18] Os sedimentos da Formação Solimões apresentam características que se enquadram como adsorventes adequados de íons metálicos, haja vista a versatilidade de minerais de argila presentes nesses sedimentos, além de outros minerais, como feldspatos e gipso.…”

Contamination Alters the Physicochemical and Textural Characteristics of Clays in the Sediments of the Peri Urban Reconquista River, Affecting the Associated Indigenous Microorganisms

“…In highly contaminated environments, exobiological factors such as temperature, pH, the concentration of ions and organic compounds, the sediment type, and the sizes of the sediment particles determine the adsorption and loading of heavy metals in sediments [8]. In this sense, Saeddi et al (2011) [9] reported that heavy metal sorption is mostly related to the load of organic matter (OM) in the Jajrood River sediments. In addition, when soils and sediments contain more than 25% of clay minerals, they are great adsorbents of heavy metals [10].…”

“…The influence of the OM on the structure of sediments must be analyzed considering the indigenous microbial assemblages and the level of pollution as these can influence the mineral composition of sediments and their clays. Reciprocally, the type of clays and their physicochemical characteristics can favor the retention of heavy metals (zinc, copper, chromium, and lead, among others) and the agglomeration of particulate organic material in a highly contaminated environment [9,31,32], thus conducive to the development of characteristic microbial assemblages.…”