Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Physico-chemical Characterization of Silt Prepared from Bijoypur Soil

T. S. A. ISLAM
Department of Chemistry, University of Dhaka, Dhaka-1000, Bangladesh

Y. ZAKER
Department of Chemistry, University of Dhaka, Dhaka-1000, Bangladesh

M. A. HOSSAIN
Department of Chemistry, University of Dhaka, Dhaka-1000, Bangladesh

M. S. ISLAM
Department of Chemistry, University of Dhaka, Dhaka-1000, Bangladesh

Abstract/ Executive Summary:

Silt obtained from fractionated Bijoypur soil based on particle size (53~140μm) was characterized by SEM (Scanning electron microscopy), LIBS (Laser induced breakdown spectroscopy), XRD (X-Ray diffraction) and FT-IR (Fourier transform infra-red spectroscopy). pHzpc (Zero point charge pH) of silt was also determined by titrimetric method. The scanning electron micrograph of silt was taken in two different magnifications. Micrographs show that the surface of silt is slightly homogenic in nature and the particle size varied between 50 and 100 μm. Elemental analysis of silt was performed by LIBS. According to this Fe, Si, Ti, Cu, Zn and Na are present in silt. XRD analysis indicates that silt fraction of Bijoypur soil is closely similar to kaolinite but it contains significant proportion of quartz. FT-IR analysis shows the presence of Zn=O, OH, Al-O-Si, Fe-O, Al-OH and Si-O bonds. The pHzpc value of silt was obtained as 6.39 ± 0.02 indicating neutrality of the surface.

Keywords: Silt, Characterization, SEM, LIBS, FT-IR, XRD, pHzpc

Location: Department of Chemistry, University of Dhaka

Start Date: 00-00-2013

End Date: 00-00-2013

Program Area: Crop-Soil-Water Management

Commodity: Land management

Objectives:

1. The objective of the present investigation was to characterize the surface of silt by SEM and pHzpc, to analyze different elements present by LIBS, molecular bonding analysis by FT-IR and phase analysis by XRD.

Methodology:

Bijoypur soil was characterized and investigation was carried out for soil sample dried at 120ºC and calcined at 500ºC and characterized by FT-IR, TGA/DTA and XRD. Bijoypur clay fraction was characterized by Zaker et al. (2013); by SEM, LIBS, FT-IR, XRD and pHzpc. Silt was prepared from the fractionation of Bijoypur (Netrokona) soil. Different methods are available for the fractionation of soil samples. But in the present investigation, Hydrometer method was used. A small portion of fractionated silt was separately taken in a Scanning Electron Microscope (SEM) sample holder and made it platinum coated using a Pt-coated auto system (JFC-1600, JEOL, Japan). Platinum coated clay was placed in the SEM sample chamber and SEM picture was taken at 20 kV with 2000 and 30,000 magnification. The prepared silt was air dried for several days. Then these were crushed and ground for making powder. The powder samples were then reserved in plastic jar. For LIBS technique, about 0.5-1.0 g silt was mixed with 1-2 drops of glue and small pellet was made. This was air dried before use. LIBS spectroscopy can be produced from high intensity laser pulse interacting with the sample producing a plasma plume that evolves with time from the point of impact of the incident laser pulse. The laser pulse usually lasts for 5 to 20 ns. LIBS spectra were taken in the spectral range of 200-900 nm for silt fraction using two gratings, One of them was 2400 ruling/mm grating blazed at 240 nm (for 200-350 nm) and the other was a grating with 600 ruling/ mm blazed at 500 nm (for 350-900 nm). The characteristic emission lines with respect to NIST atomic spectral reference data-2010 for corresponding elements with oxidation states are presented. The pH of silt surface at zero point charge (pHzpc) was determined by the method suggested by titrimetric process. 0.1 g of silt was added to four identical portions of 40 mL 0.1 M NaCl solution of pH 7. The mixtures were agitated for 24 hours in thermo mechanical shaker (SWB-20, HAAKE, Fisons Ltd, Germany). Two bottles of suspension were titrated; One with 0.05 M HCl and another with 0.05 M NaOH using micro burette (± 0.01 mL). During the titration, the constant pH reading was taken carefully. From other two bottles, the supernatants after filtration were titrated similarly; one with 0.05 M HCl and another with 0.05 M NaOH as described above. From above titration four curves were obtained for the plot of pH versus volume of acid or alkali. Using these plots in a same scaled single graph differences in volume (ΔV) at constant pH for suspension and supernatants were estimated. Using these data, ΔV versus pH plot was obtained for 0.1 M NaCl. Similarly another plot was obtained for 0.01 M NaCl solution. These two plots intersect at a point defined as surface zero point charge pH (pHzpc) of silt.

Source of Information: J. Asiat. Soc. Bangladesh, Sci. 39(1): 53-60, June 2013

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

The pH of the zero point charge is the pH of the solution at which the charges on the surface (-ve or +ve) are balanced by the addition of acid or alkali. In Fig. 3 the point of intersection of two curves is the pHzpc of silt and it was estimated as 6.39 ± 0.02. The value is almost equal to the pHzpc of clay (6.40±0.02). The pHzpc of silt indicated that the surface of silt acts as a positive charge at 6.39±0.02 and below, whereas negative charge at pH is higher than 6.39±0.02. These results indicate that surface of silt fraction is almost neutral suggesting that the cationic adsorbate would favor basic medium and anionic adsorbate would favor acidic medium. It can be concluded that the particle size and shapes of silt are not uniform and the sizes are in between 50 to 100 μm. Many metals bonded with oxygen are present in silt. XRD lines and d-values indicate that silt fraction resembles more to quartz than kaolinite.

Knowledge Management: Journal