A coagulation treatment study was conducted using both natural (sago and potato flour) and commercial (poly aluminum chloride and aluminum sulfate) coagulants in semiconductor wastewater. The effects for settling time and dosage of the coagulants as well as their interactions on the reduction of chemical oxygen demand (COD) and turbidity were investigated using a three level factorial design, Response Surface Methodology (RSM). Sago concentration showed more influence on the COD and turbidity reduction than settling time, with concentrations lower than 1.5 g L −1 giving the better reduction. The interaction of settling time and concentration on the COD and turbidity were observed when using potato starch. Concentrations higher than 1.5 g L −1 potato starch reduced the COD and turbidity better. The polyaluminium chloride and ammonium sulphate revealed that lower concentrations (0.02-1.0 g L −1 ) and longer settling time (30-60 min) gave the greatest reduction in COD and turbidity.
A rapid identification, classification and discrimination tool, using Fourier Transform Infrared (FTIR) spectroscopy combined with Principal Component Analysis (PCA), was developed and applied to determine the profile of the Supercritical Fluid Extraction (SFE) of Parkia speciosa seeds under various temperature and pressure conditions (313, 323, 333, 343, 353 and 363 K and 20.68, 27.58, 34.47, 41.37, 48.26, and 55.16 MPa). The separation and identification of the compounds was carried out by Gas Chromatography coupled with Time of Flight Mass Spectrometry (GC/TOF‐MS). This technique has made it possible to detect the variability obtained under different SFE conditions and the separation of different chemical compounds in P. speciosa seeds. The FTIR‐PCA results were verified by GC/TOF‐MS, and the FTIR‐PCA method successfully identified the unsaturated carboxylic acids with the highest percentage area under the different conditions.
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