Son Van Dang

Date of Publication

2009

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Chemical Engineering

Subject Categories

Chemical Engineering | Engineering

College

Gokongwei College of Engineering

Department/Unit

Chemical Engineering

Thesis Adviser

Leonila C. Abella
Pag-asa D. Gaspillo
Joseph Auresenia
Junjiro Kawasaki

Defense Panel Chair

Susan M. Gallardo

Defense Panel Member

Josephine Q. Borja
Jonathan Salvacion
Yolanda P. Brondial
Annaliza Rollon

Abstract/Summary

Arsenic is well-known as one of the most toxic elements. Recently, arsenic (As) contamination of groundwater has become a major concern on a global scale, especially in Bangladesh, India and South-East Asia. A promising method that can be considered as an efficient and low-cost method for wide-scale application in rural areas is adsorption, using appropriate, readily available and cheap adsorbents. This study aimed to investigate the removal of arsenic from simulated groundwater using the sequential arrangement of laterite (LA) and iron-modified activated carbon (AC-Fe) in a packed column through experiments and mathematical modelling. Also, other alternative potential adsorbents: LA from Vietnam, rice husk carbon (RH), zero-valent iron (ZVI) and iron oxide (IO) were also investigated to enhance the flexibility and feasibility of application of the arsenic treatment approach developed by this study. The results from batch experiments showed that the Langmuir isotherms and pseudo-second order best described the equilibrium and kinetics of the arsenic adsorption process from simulated groundwater, using LA and AC-Fe under experimental conditions. The adsorption capacities are 0.48 and 1.18 mg/g, respectively. The following appropriate parameters for operation of an adsorption column with diameter of 0.025 m and bed height of 0.5 m are: LA/AC-Fe ratio of 0.3 m/0.2 m, flow rate of 4 to 6 mL/min (or space velocity of 0.98-1.47 m3/m3 h), around neutral pH of 7-8, and initial arsenic concentration of 0.4-0.6 mg/L, corresponding to the breakthrough time of more than 100 hours. The behaviour of the column observed from mathematical modelling was similar to that from column experiments. The breakthrough points from modelling were very close to the experimental ones. The results from this study could facilitate the design of an adsorption column or filter for arsenic treatment using sequential combination of LA and AC-Fe for household use. This could be an efficient and feasible way to remove arsenic from groundwater for ready application in the rural areas, especially in developing and poor countries. The use of the combination of LA and RH-Fe, IO or ZVI is another configuration which can remove arsenic efficiently and flexibly.

Abstract Format

html

Language

English

Format

Electronic

Accession Number

CDTG004460

Shelf Location

Archives, The Learning Commons, 12F Henry Sy Sr. Hall

Physical Description

xviii, 241 leaves ; 28 cm.

Keywords

Groundwater -- Pollution; Groundwater -- Quality. Groundwater

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