The biosorption of phosphate using modified cassava waste were studied. Cassava pulp was modified in methylamine for the adsorption of phosphate ion in aqueous solution. XRD SEM and FTIR result confirmed the surface modification of modified cassava waste. The adsorption experiments were conducted in a batch reactor. The studied parameters included pH contact time and initial concentrations. The amount of phosphate in the solution was measured by Vanadomolybdophosphoric acid method. Optimum conditions of adsorption were 0.10 g of modified cassava waste pH 4 and 5 hour of contact time at 25 mg/L of initial phosphate concentration. Kinetic of adsorption were studied by using the pseudo-first and pseudo-secondorder models at room temperature. The results indicated that the pseudo-second-order model best described adsorption kinetic data. The Langmuir and Freundlich adsorption models were applied to describe the isotherms and isotherm constants. The adsorption of modified cassava fitted well with the Langmuir model and the maximum adsorption capacity of 5.128 mg/g; and the active site of adsorption was amine functional group. Phosphate released in water reach equilibrium within 4 days.

The aims of this study were developed geopolymer matrix for controlled release amoxicillin antibiotic drug in the in vitro gastric and intestines (pH 1 and pH 6.8 temperature 37 ºC conditions). Three formulations of geopolymer tablets (GeAmSF5 GeAmSF7.5 and GeAmSF10) which different silica fume content were used in this study. Geopolymer tablets were measured compressive strength and characterized by using 3D laser microscope Scanning electron microscope (SEM) X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The amoxicillin release was analyzed by UV-VIS spectrophotometer. It was found that amoxicillin in geopolymer tablet was more resistance with various extraction solvents (ethanol water 50 oC pH 1 and 12 solutions) than amoxicillin commercial tablet in 2 hours. Moreover the amoxicillin constantly release from geopolymer matrix after 3 hours in both in vitro gastric and intestines. However amoxicillin was more release in gastric than intestines condition due to the strong acid leached aluminum ion causing damages geopolymer structure. Mathematical modeling of amoxicillin release from geopolymer matrix was fitted best with Higuchi model indicating diffusion of the drug out of matrix.

The biosorption of Rhodamine B using modified water hyacinth roots was studied. The adsorption experiments were conducted in a batch setup. Parameters affecting the adsorption of Rhodamine B including pH of a solution adsorption time adsorbent dose and dyes concentration were investigated. With the 80 mg/L Rhodamine B solution of pH 6.0 adsorption time of 60 min and 0.10 g of modified water hyacinth roots the kinetic models pseudo-first order and pseudo-second order kinetic model were applied to examine the kinetic adsorption. The adsorption kinetic data correlates with pseudo-second order kinetic model. The Langmuir and Freundlich adsorption models were applied to describe the isotherms and isotherm constants. Adsorption isotherm data correlates with Langmuir adsorption model. The maximum adsorption capacity of modified water hyacinth roots for Rhodamine B was found to be 63 mg/g