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Effect of demineralization on the physiochemical structure and thermal degradation of acid treated indigenous rice husk

100%

Aslam U. , Ramzan N. , Iqbal T. , Kazmi M. , Ikhlaq A.

Polish Journal of Chemical Technology

2016

tom Vol. 18, nr 3

117--121

Energy generation from biomass presents some serious problems like slagging, fouling and corrosion of boilers. To address these problems, demineralization of biomass is performed using different leaching agents. This study is focused on determining the influence of leaching agents and leaching time on the physiochemical structure of rice husk during demineralization. Dilute (5% wt) solutions of HCl and H2SO4 were used for the demineralization of rice husk separately with leaching time of 15, 60 and 120 minutes. It is shown that H2SO4 exhibited higher removal of alkali and alkaline earth metals (AAEM) comparatively as depicted by the 34.2% decrease in ash content along with an increase of 7.10% in the heating value. The acid has been seen to induce more notable changes in physiochemical structure as depicted by the FTIR spectra and SEM micrographs. The thermal degradation behavior of the demineralized rice husk has also been reported.

Effect of heavy metal pollution on mineral absorption in sunflower (Helianthus annuus L.) hybrids

72%

Aslam U. , Ahmad I. , Hussain M. , Khan A. , Ghani A. , Mustafa I. , Jalal S. , Aqeel M. A. , Asif S. , Ahmed H.

nr 01

The present study was conducted in a potted experiment to examine the effects of chromium pollution on absorption of mineral nutrients and some morphophysiological attributes of two sunflower (Helianthus annuus L.) hybrids (FH-331 and FH-259) in the presence and absence of ethylene diamine tetra acetic acid (EDTA) used as a chelating agent. Four concentrations of chromium (Cr³⁺) i.e., 0, 20, 30 and 40 mg kg⁻¹ with and without 0.3 g kg⁻¹ , EDTA as chelating agent were applied to 25-day-old sunflower plants. A gradually decreasing trend in absorption of all minerals and other parameters studied were observed. Different treatments of Cr³⁺ as well as Cr³⁺ and EDTA significantly reduced root and shoot fresh weight; however, root, shoot and achene Cr³⁺ contents of two sunflowers hybrids under higher chromium and EDTA stress varied significantly whereas movement of Cr³⁺ contents to leaves was non-significant. Absorption of Na⁺, K⁺, N₂ and P through roots and shoots significantly reduced with increasing concentration of Cr³⁺ treatments. In fact addition of EDTA to the medium further enhanced the toxicity of chromium.