Commercially available Multiwalled Carbon Nanotubes (MWCNTs) were refluxed with nitric acid in order to improve the density of the acidic surface functional groups. The formation of oxygen containing functional groups may lead to surface enhancement of MWCNTs for further modifications. The crude MWCNTs were refluxed in nitric acid at 100 °C for time ranging between 3 to 24 h. The influence of treatment time on crystalline structure was investigated using X-Ray Diffraction (XRD); the results confirmed that all treated MWCNTs are crystalline. The density of the surface functional groups on treated MWCNTs was examined by Fourier Transform Infrared (FTIR). The FTIR spectrums revealed a strong vibration band at 1739, 1219, 1369 cm-1that indicates covalently bound acidic surface functional groups existed on the treated MWCNTs. The amount of acidic groups increased with the reflux time up to 15 h treatment as measured by an acid-base Boehm titration. The vibrational spectroscopy of these functional groups also increased with the increasing reflux time.

Top spray granulation process is a common technique used widely in pharmaceutical, food and special chemical modification for fertilizer manufacturing. Nevertheless, there is still a lack of studies regarding to the description of controlled parameters with dynamic correlation in targeting to produce urea granules. Thus, this research was carried out to introduce the crucial applied process parameters using top spray technique for paddy urea fertilizer production.The acquisition process parameter readings were verified by obtained yield of urea granules (UG) which featured as an optimum particle diameter size from 2 mm to 6 mm with reasonable hardness (crush strength) in range 2.0 kg/granule to 4.0 kg/granule, these criteria were required as a slow - release mechanism during soil adsorption interaction in paddy field to reduce amount of fertilizer consumption. Three significant parameters have been selected namely as air inlet temperature, the viscosity of binder solution and rate of top spraying from starch liquid binder to generate greater UG size from wet granulation interaction with smooth coalescence and consolidation growth . The data classification was screened by One-Factor-at-a-Time (OFAT) 101 method and supported by 2 levels and 3 factors (23 ) of full factorial design for clear description to vindicate the critical parameter required during urea granulation using fluidized bed granulator corresponds to low energy consumption and economical process. The obtained parameter readings and findings of UG features were useful to be applied further for detail investigation on next stage regarding to agglomeration profile and mechanism using CCD camera and PDA monitoring devices.

Studies in urea granulation process using Top Spray Fluidized Bed Granulator (TSFBG) is still limited and requires in-depth research about the effectiveness and influence of droplets to the formation of urea granule (UG). Rate and time interval of spraying technique (Pulse) significantly influence the physical properties of urea granules. Cassava starch dissolves in water was selected as the binder released at various time interval to observe impact of spray droplet on UG size formation. Using Taguchi Method, the study had identified three leading factors contributed to the formation of droplet size namely volume of binder (VOB), time pulse of spraying (TPS) and spraying rate (SR). These factors were then evaluated in terms of the influence on response as signal-to-noise analysis (S/N ratios) from Taguchi to validate UG size in range 2 mm to 4 mm from screening process with respect to the actual experimental data. These results were useful for future experiment reference to determine pressure drop and surface contact during interaction between droplet and urea powder particles using TSFBG to obtain uniform UG size and smooth surface layer with reasonable hardness.