Alkaline Pre-Treatment of Coal Fly Ash as Bio-Silica Fertilizer

This study deals with the pre-treatment of coal fly ash (CFA) by using alkaline substance to improve water solubility of Si which in turn readily available to the plants. Selected weight ratios of CFA/NaOH (s:s) were tested and the highest H4SiO4 yield ratio was selected for further study. X-ray diffraction and scanning electron microscopy analyses were performed to confirm the evidence of structural changes of the CFA upon alkaline treatment. To improve SiO2 dissolution, seven Si-solubilizing fungi, i.e., Aspergillus niger BCC194, A. niger K0909, A. niger A1601, Trichoderma polysporum, T. viride, T. pseudokoningii, and Trichoderma spp, were each inoculated onto pre-treated ash. The results indicated that the relationships between ratio of CFA/NaOH and total and soluble Si were linier (R2 = 0.97** and 0.96**, respectively). Total SiO2 values range from 10.43% to 13.02%, whereas soluble Si contents were 2.30% - 2.64% improved about 300 times compared to un-treated CFA. Both XRD and SEM analyses indicated that alkaline treatment to CFA caused particle damages resulting in increasing soluble Si. Inoculation of pre-treated CFA by T. polysporum up to twelve days of incubation yielded the highest soluble Si. Each fungal species grown on Bunt & Rovira solid media enriched with CFA as Si-source expressed significantly different ability in solubilizing Si from CFA. Citric acid was shown to be stronger compared to acetic and oxalic acids in solubilizing Si from CFA.

The Use of Molecular-Sieving Materials as Ameliorant for Peat Degradation in the Tropics

Peat utilization for agriculture expansion area is commonly found extensively in tropical region during the last few decades. Most agronomical practices involve drainage resulting decomposition of organic materials and increasing drying. This study was carried out to determine the potential use of molecular-sieving materials (MPMs) as an ameliorant for peat soil targeted for reducing the potential hazard of peat degradation. A clinoptilolite-zeolite, empty fruit bunches of oil palm biochar (EFBOPB), and their combination were studied its characteristics to evaluate the ability in adsorbing water and green-house gas emission. A series of laboratory analyses were conducted to determine physicochemical and mineralogical characteristics of both materials and its combination, including elemental analyses, cation exchange capacity (CEC), pH, ore spaces, water holding capacity (WHC), and adsorption capacity for CO2, NH3, and N2. The study revealed that 100 - 150 mesh size of zeolite possesses higher values of CEC, WHC, and adsorption capacity for CO2, NH3, and N2 compared to EFBOPB, whereas the latter indicated a higher organic-C content and pore spaces. Combination of 75% (w/w) zeolite and 25% (w/w) EFBOPB showed the best composition of these two MPMs to improve WHC of peat and as consequences slowing down the firing process of the peat. Based on the gas adsorption data, it could be assumed that the mixture of MPMs studied could be considered as an effective material to reduce risk of peat from fire potential hazard and retard GHG emission.

The Potential Use of Natural Clinoptilolite Zeolite for Crude Oil Spill Removal from Sea Water

Accidental spillage or drainage from land of crude oil to the marine environment will potentially cause serious damage to the environment and marine life. Many efforts have been focused on the use of most efficient adsorbent to remove the oil and/or oil-decomposing agent from the water. The current study was aimed at to evaluate the most abundantly-available natural zeolite dominated by clinoptilolite mineral and pronounced molecular sieve characteristics as crude oil spill removal in sea water. Bayah-originated zeolite was characterized by using X-ray diffraction (XRD) analysis, pore distribution and average size, gas sorption capacity, and scanning electron microscopy (SEM). A laboratory experiments were conducted by reacting a 100-mesh zeolite with and without microbial enrichment to crude oil in a 250 mL sea water (3.7% NaCl and pH 6.7) jar at different oil/zeolite ratios,??i.e.?50%, 100%, 200%, and 400% (v/w) with three replicates. Observations were made on the stability of zeolite-oil mixture for one week, the weight of zeolite mixed with oil, the oil adsorbed by the zeolite, and free oil after 24-hrs settling. The results indicate that zeolite has highly potential as crude oil adsorbent and the highest oil sorption obtained at zeolite/oil ratio of 1:1 with 86.3% oil adsorbed or 0.87 mL oil per gram zeolite. Enrichment of zeolite with?Bacillus subtilis?improved the adsorbed oil by the mineral.