Exchange of heavy metals in coconut coir

Date

7-1991

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Aloysius U. Baes

Abstract

The titration behavior (pH 2.5 to 9) of coconut coir and sulfuric acid-treated coir samples were determined using standard sodium hydroxide solution. Similar titrations were made with coconut coir and sulfuric acid-treated coir in the presence of different metal ions (Ca2+. Cu2, Pb2+ and Ni2+). The titration curves of both samples were similar to that of weak acid exchangers. Calculated dissociation constants were 2.29 x 10-4 for the coconut coir and 1.63 x 10-4 for the sulfuric acid-treated coir. The addition of metal ions generally shifted the titration curve towards an increasing volume of added standard NaOH for every unit increase in pH. The over-all trend in volume was Ca2+ < ,N2+ pb2+ cu2+ for both coconut coir and sulfuric acid-treated coir samples. The increase in volume was attributed to an increasing tendency of the different metal ions to exchange with H' and ha+ ion on the exchanger sites. This exchange behavior was confirmed with the analysis of the metal ions absorbed by the coir samples. Concentration of metal ions before and after equilibration with the coir samples in solutions maintained at. pH 4, 6 and 9 was determined. Thu selectivity of untreated coir for the metal ions studied was ca2+ < Ni2+- < pb2+ < c,2+. at pH greater than 6. At pH 6 or less, the order of preference was Ni2+ < Ca2+ < Pb2+ < Cu2+. pH 9, the selectivity of treated coir was Ca2+ < Ni2+ = Cu2+.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 1991 C4 M47

Document Type

Thesis

This document is currently not available here.

Share

COinS