Optimization of soil washing conditions using EthyleneDiamineTetraacetic Acid (EDTA) for the removal of nickel from contaminated soil

Date

6-2016

Degree

Bachelor of Science in Chemical Engineering

College

College of Engineering and Agro-Industrial Technology (CEAT)

Adviser/Committee Chair

Monet Concepcion M Detras

Abstract

Soil remediation is essential to avoid detrimental effects to the environment and human health. In this study, soil washing with ethylenediaminetetraacetic acid (ADTA) was used to remove nickel from contaminated soil. Prior to soil washing, the physico-chemical characteristics of the soil were determined including soil pH (7.36), cation exchange capacity (25.47 meq/kg soil), organic matter (1 %w/w), and organic carbon (0.378 %w/w). The soil was examined to have 26 % (w/w) sand, 36 % (w/w) silt, and 38 % (w/w) clay. Using sequential extraction, the nickel distribution was evaluated at different soil fractions- exchangeable (3.56%w/w), reducible (7.44 % w/w), organics (7.70% w/w), and residual (81.31 %w/w). The two-level factorial experiment showed that soil washing parameters such as pH (4 and 7), EDTA concentration (0.025 M and 0.05 M), and soil loading (0.04 g/mL and 0.10 g/mL) and their interactions, were significant on the amount of nickel removed from soil (expressed as mg Ni/kg soil). Decreasing the solution pH and soil loading and increasing EDTA concentration increased nickel removal. Optimization using Box-Behnken experimental design resulted to a quadratic log10 model which was used to predict the highest nickel removal of about 1160.86 ± 176.49 mg Ni/kg soil at the optimum conditions of pH 3, 0.1375 M EDTA, and 0.05 g/mL. Using these conditions, the preliminary cost of the soil washing technology was calculated to be about 1760 Php per kilogram of soil treated which translates to 1516.12 Php per gram of nickel removed.

Language

English

Location

UPLB College of Engineering and Agro-Industrial Technology (CEAT)

Call Number

LG 993.5 2016 E62 G37

Document Type

Thesis

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