Evaluation of the combined effects of initial copper concentration and pH on the copper uptake of Philippine giant bamboo (Dendrocalamus asper) under hard water conditions

Date of Publication

12-2018

Document Type

Master's Thesis

Degree Name

Master of Science in Chemical Engineering

Subject Categories

Chemical Engineering

College

Gokongwei College of Engineering

Department/Unit

Chemical Engineering

Thesis Adviser

Lawrence P. Belo
Cynthia F. Madrazo

Defense Panel Chair

Nathaniel P. Dugos

Defense Panel Member

Josephine Q. Borja
Joseph L. Auresenia

Abstract/Summary

Copper contamination is a known cause of river death. Through phytoremediation, it is possible to use plants to remediate pollution by decreasing heavy metal contaminations, such as copper, back to habitable levels. Although phytoremediation is not a new technology, most of the studies dealt with the individual effects of heavy metal concentrations on specific plants, and the combined effects of environmental factors are not well-established. In this study, the combined effects of initial copper concentration, pH & plant age on the copper uptake of Dendrocalamus asper (Philippine Giant Bamboo) under hard water conditions have been investigated. Initial copper concentration, pH and water hardness may interact to affect the speciation of copper, and in turn, the copper uptake. As such, D. asper was planted in hydroponics at varying levels of initial copper concentration, pH, water hardness & plant age. Liquid samples were then extracted from the hydroponic solutions and analysed using AAS. Increase in initial copper concentration led to increased copper uptake. At high copper concentrations (>3.81 ppm), a lower pH (5) is desired for phytoremediation (up to 0.76 mg Cu/g plant in 16 days); below 3.81 ppm, the effect of pH on copper uptake is minimized. The uptake rate over the first 34 days was analyzed using a general nth order kinetic model. It was found to follow a kinetic equation with dddd dddd = −0.0013CC2.71 where C is in ppm and t is in days. The possible effect of plant age was also studied. On a per mass basis, the younger plants (2 months) proved to be better copper phytoremediators (up to 1.34 mg Cu/g plant in 16 days). Some additional experiments were also conducted in order to close the mass balance between copper loss from hydroponics and the copper absorbed by the plant biomass. Approximately 6 - 32% of the Cu loss was absorbed by the plant, while the balance may have precipitated as copper (II) oxalate or copper (II) citrate due to the diffusion of organic acids from the cytosol. Phytoremediation using D. asper was most effective at high copper concentrations (20 ppm) and low pH (5), and when two month old plants were used. Overall, initial copper concentration, pH and plant age were found to have a significant effect on copper uptake.

Abstract Format

html

Note

Both bachelor's and master's theses

Language

English

Format

Electronic

Accession Number

CDTG008273

Keywords

Copper—Environmental aspects; Bamboo--Philippines; Phytoremediation

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Embargo Period

4-30-2025

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