Research student profile: Irshad Bibi

Project title

Acid buffering capacity of clay minerals in acid sulfate soils.

Project overview

My PhD research is aimed to determine the dissolution rates of monomineralic clay samples and minerals isolated from inland acid sulfate soil samples and their acid buffering capacity in acidic soil solutions.

Study of mineral dissolution rates is important to understand and control environmental effect of acid mine drainage, soil acidification and other geological processes. Weathering of minerals resulting from the interaction of dissolved H+ and OH-, with the surface of rocks and minerals, is one of the fundamental natural processes in element cycling. This process is of critical importance in maintaining the proton balance of soils. Work has been done on clay mineral weathering; however, there is still a need to do a comparative acid dissolution study on pure clay mineral samples and on clay fraction separated from soil samples.

To achieve the above mentioned objectives, a set of dissolution experiments will be carried out on pure minerals: kaolinite, illite and smectite and on the clay fraction isolated from inland acid sulfate soils. The dissolution experiments will be carried out in stirred flow-through reactors at a constant temperature of 25°C. Feed solutions of specific pH (pH 1, 2, 3) will be prepared by adding reagent grade H2SO4 to double deionised water. In experiments designed to study the effect of ionic strength on mineral dissolution rate, different amounts of NaCl will be added in to the input solutions. Concentrations of Al, Si and pH will be monitored throughout the experiments. Surface normalized dissolution rates will be calculated based on Al and Si steady state concentrations. Soil samples and pure clay minerals will be characterized by XRD, XRF, SEM, and BET techniques before and at the end of each experiment.

From this work, I would be able to determine the dissolution rates of clay minerals in acid sulfate soil solutions; assess the important role of aluminosilicates in the acid neutralizing processes in acid sulfate soils and to examine the mineralogical transformations of clay minerals in acid sulfate soil solutions.

Background

I am an international student from Pakistan. I have done my BSc. (Hons) Agri from University of Agriculture Faisalabad, Pakistan in year 2004 taking soil science as a major subject. I have done my MSc. (Hons) Agri from University of Agriculture Faisalabad (Institute of Soil and Environmental Sciences), Pakistan in year 2006. My master research project was on studying the growth response of rice to copper and zinc application in soil. I have started my PhD in March 2008.

I have been granted an USydIS scholarship.

During four years of BSc. (Honors) study, I received merit scholarship every year for achieving >80% marks in university exams.

In the first year of my PhD, I had a chance to attend a training course at Adelaide on identifying and assessing acid sulfate soils in the Murray Darling Basin. In June 2010, I have attended an International Trilateral Meeting in Spain organized by the Clay Mineral Society, the Clay Science Society of Japan and the Spanish Clay Society and presented a poster from my PhD research. My supervisor A/Prof. Balwant Singh also presented a talk from my PhD work at the meeting.
In August 2010, I presented my work as a poster at World Congress of Soil Science, Brisbane 2010.
I also presented my work as an oral and a poster presentation in August 2010 at Australian Clay Minerals Society’s conference held in Brisbane following the World Congress of Soil Science.

Publications

  • Bibi I, Singh B and Silvester E (2010) Experimental study of the effect of saline-acidic conditions on illite dissolution. Presented as a talk and published abstract in the proceedings of SEA-CSSJ-CMS meeting on Clays Seville, Spain 2010 (June 8-10).
  • Bibi I, Singh B and Silvester E (2010) Dissolution of kaolinite, illite and montmorillonite in acid-saline solutions. Presented as a poster and published abstract in the proceedings of SEA-CSSJ-CMS meeting on Clays Seville, Spain 2010 (June 8-10).
  • Bibi I, Singh B and Silvester E (2010) Dissolution of phyllosilicates under saline-acidic conditions. Presented as a poster and a published paper in the proceedings of 19th world Congress of Soil science, Brisbane (1-6 August) 2010.
  • Bibi I, Singh B and Silvester E (2010) Measuring dissolution rates of illite in saline-acidic solutions using flow-through reactors. Published abstract in the proceedings of the Australian Clay Minerals Society’s 21st conference, Brisbane 7-8 August, 2010 (Poster presentation).
  • Bibi I, Singh B and Silvester E (2010) Akaganéite precipitation in inland acid sulfate soils of south-western New South Wales, Australia. Published abstract in the proceedings of the Australian Clay Minerals Society’s 21st conference, Brisbane 7-8 August, 2010 (Oral presentation).
  • Bibi I, Singh B and Silvester E (2010) Clay Minerals Dissolution in Acid Sulfate Environment. The Centenary Research Symposium of the Faculty of Agriculture, Food and Natural Resources, The University of Sydney, Friday 4 June 2010 (Poster presentation).
  • Bibi I, Singh B and Silvester E (2010) Dissolution study of illite in saline-acidic solutions at 25°C. (Submitted to Geochimica et Cosmochimica Acta on 20-09-2010).
  • Bibi I, Singh B and Silvester E (2010) Akaganéite precipitation in inland acid sulfate soils of south-western New South Wales (NSW) (In preparation for submission to Geochimica et Cosmochimica Acta).

Contact

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