REMOVAL OF METAL IONS FROM BÍO BÍO RIVER WATER BY LIQUID-PHASE POLYMER-BASED RETENTION TECHNIQUE

Abstract

ABSTRACT Water-soluble poly(2-acrylamidoglycolic acid) (PAAG) was synthesized by radical polymerization and characterized by FTIR spectroscopy and potentiometric titration. Subsequently, this polymer was used as extracting reagent of metal ions using LPR technique, through washing and enrichment methods. By the washing method, the selective retention (100 %) of Al 3+ was obtained at pH 2.36. The removal of monovalent and divalent ions was maximum for all the metal ions at pH 5.The maximum retention capacity of some metal ions by PAAG was studied by enrichment method using water of Bio Bio river containing metal ions. The higher retention percentage for Al 3+ ion indicates that PAAG could be used as an extracting reagent for Al ions from Bio Bio river samples. Keywords: Bio Bio river, Metal ions, Ultrafiltration, Membranes. e-mail: epereira@udec.cl 1. INTRODUCTION In water sources, the metal ion pollutants may be concentrated, diluted o transported through of hydrologic cycle, affecting finally domestic waters. From of toxic point of view, metals are not biodegradables and therefore are accumulated in the living organisms exerting toxic actions [1-3].Some of the heavy metals are among the most harmful of the elemental pollutant. These elements include essential elements like iron as well as toxic metals like lead, cadmium, and mercury. Most of them have a great affinity for sulfur and attack sulfur bonds in enzymes, thus immobilizing the enzymes. Carboxylic acid and amino groups of proteins are also chemically bound by heavy metals. Cadmium, copper, lead, and mercury ions bind to cell membranes, hindering transport processes through the cell wall. Heavy metals may also precipitate phosphate biocompounds or catalyze their decomposition [4-6]. Aluminum is the most abundant metal naturally present in air, soil, and water. Therefore, environmental exposure to aluminum is potentially possible. Particularly, it is believed that aluminum is responsible of several diseases that are related with neuronal damaged [7,8]. It enters to the brain and may contribute to Alzheimer’s disease and other neurodegenerative diseases [9]. Aluminum is also able to give rise to toxicity in the bones and hematopoietic system in humans [10]. This fact has increased the interest for study the aluminum content and possible removal from domestic waters sources. One of the most promising techniques for solve this problem is the application of separation methods based on membrane process [11,12]. In comparison with conventional systems for water and wastewater treatment, these have several advantages, such as easy operation and control, few chemical additives are used in the process, and costs of operating and maintenance are low [12].Recently, the separation of toxic inorganic species has been investigated by a hybrid method using membranes coupled to water-soluble functional polymers [13]. This method is known as the