Preparation and comparison of the effectivity of salicylic acid- modified chitosan and chitosan in the removal of arsenate from aqueous mixture.

Date

4-2012

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Peralta, Milagros M.

Committee Member

Rodriguez, Evelyn B. Fajardo, Norma N.

Abstract

Salicylic acid-modified chitosan (SAMC) was prepared by utilizing the Mannich reaction between formaldehyde, salicylic acid, and chitosan using a molar ratio of 5:1:1. The yield of the salicylic acid modified chitosan was1.57g SAMC per 1.00g chitosan at one and ten grams scale. SAMC was characterized by IR and titrimetric methods as well as by physical characterization. Percent deacetylation of SAMC was found to be 32.20%. The equilibrium water content of the hydrogel was found to be 39.35%. The IR spectra showed some evidence of the presence of salicylic acid but many peaks were obscured by the dominant bands attributed to chitosan. SAMC was tested for its effectivity in adsorbing arsenic as arsenate using a colorimetric method that utilizes the reaction of ethyl violet with molybdenum yellow which gives a blue color. It was found out that 1.0% (w/v) SAMC could adsorb 85.56% of arsenic from 100ppm arsenic solution while the 1% (w/v) unmodified chitosan could only adsorb 70.38% arsenic from 100ppm arsenic solution. The adsorption isotherm of SAMC was plotted and found to follow the Freundlich adsorption model. This implies that there is an infinite adsorption at infinite concentration and the adsorbed layer is not confined to a monolayer and lateral interactions between adsorbate molecules may be possible. The computed maximum adsorbate intake to the saturation capacity of the sorbent (qmax) was 1.2795 g-1. The kinetic model of SAMC was determined to follow the pseudo second order kinetic model which implies that the rate limiting step is the chemical sorption. The computed rate constant (k) was 0.1081 g/(mg•min).

Language

English

Location

UPLB Main Library Special Collections Section

Call Number

Thesis

Document Type

Thesis

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