Coagulantes y floculantes naturales usados en la reducción de turbidez, sólidos suspendidos, colorantes y metales pesados en aguas residuales

Abstract

In this monograph, information on the coagulation and flocculation capacity of heavy metals, suspended solids, turbidity, dyes and chemical oxygen demand in wastewater was obtained by applying extracts derived from natural sources. For this, we collected and characterized bibliographical information of fifteen plant species and two extracted from animals, which are reported in the scientific literature with coagulant and flocculant activity and convert them into substituents of chemicals such as aluminum sulphate Al2 (SO4 ) 3 and ferric chloride (FeCl3) known to be the most commonly used chemical coagulants in the water purification process. The present study, the organs used for each plant, identify the active coagulant agents of such species, such as proteins, tannins and carbohydrates mainly. In order to characterize the optimum and practical conditions for coagulation and flocculation processes, it is fundamental to look for reports of the chemical mechanism of the underlying coagulation and flocculation phenomenon. It is important to note that for optimum results in the coagulation and flocculation activity it is necessary to take into account the effects of some factors such as water pH, coagulant dose and initial concentration of contaminants. However, in some plant species, pH does not significantly alter coagulant capacity in relation to inorganic coagulants (Mishra et al., 2002). The biopolymers reviewed in the different databases have proved to be efficient with high pollutant removal values, however there is a need to explore and extend the study on an industrial scale.