Raja Kamarulzaman Raja Ibrahim

Temperature and air–water ratio influence on the air stripping of benzene, toluene and xylene

Volatile organic compounds in water and wastewater can be removed using air stripping. The effects of temperature and air-water ratios on the air stripping of benzene, toluene and xylene (BTX) from wastewater have been examined at a temperature range of 30–50°C and air-water ratios of 20–100. Removal efficiencies of >99%, >93% and 93% for BTX, respectively, were obtained at 50°C and air-water ratios of 100. The removal efficiencies increase non-linearly with temperature and air-water flow ratio. The effects of increasing temperature on the removal efficiency were found to be more significant at temperatures between 30 and 35°C than at 45 and 50°C. The effects of increasing water-air ratios on the removal efficiency were more significant at air-water ratios of 20–60 than at 80–100. The results indicate that a high removal of BTX can be achieved by operating the air stripper at high temperature conditions even at relatively low air-water ratios and vice versa.

Application of a packed column air stripper in the removal of volatile organic compounds from wastewater

Abstract Addressing environmental degradation and ensuring environmental sustainability are inextricably linked to all methods of reducing volatile organic compounds (VOCs) from the environment. A packed column air stripper is a typical example of such technologies for the removal of VOCs from polluted water. The present review is devoted to the applications of a packed column air stripper and, in comparison with previous reviews, presents further elaborations and new information on topics such as modeling and simulation of the dynamic behavior of the air stripping process in a packed column air stripper. The paper observed that a knowledge gap still exists in the synthesis of this knowledge to formulate practically applicable mathematical relationships to describe the process generally. Therefore, further researches are still required in the area of air stripper performance optimization, particularly in the development of a mathematical model and the optimization of an air stripper using a statistical experimental design method. Such a determination is critical to the understanding of the interactive effect of process variables such as temperature, air-to-water (A/W) ratio, and height of packing on air stripper performance.

A simple approach for rapid detection and quantification of adulterants in stingless bees (Heterotrigona itama) honey

In this study, we propose an easy approach by combining the Fourier transform infrared and attenuated total reflectance (FTIR-ATR) spectroscopy together with chemometrics analysis for rapid detection and accurate quantification of five adulterants such as fructose, glucose, sucrose, corn syrup and cane sugar in stingless bees (Heterotrigona itama) honey harvested in Malaysia. Adulterants were classified using principal component analysis and soft independent modeling class analogy, where the first derivative of the spectra in the wavenumber range of 1180-750cm-1 was utilized. The protocol could satisfactorily discriminate the stingless bees honey samples that were adulterated with the concentrations of corn syrup above 8% (w/w) and cane sugar over 2% (w/w). Feasibility of integrating FTIR-ATR with chemometrics for precise quantification of the five adulterants was affirmed using partial least square regression (PLSR) analysis. The study found that optimal PLSR analysis achieved standard error of calibrations and standard error of predictions within an acceptable range of 0.686-1.087% and 0.581-1.489%, respectively, indicating good predictive capability. Hence, the method developed here for detecting and quantifying adulteration in H. itama honey samples is accurate and rapid, requiring only 7-8min to complete as compared to 3h for the standard method, AOAC method 998.12.

Identification of Lactobacillus spp. and Fructobacillus spp. isolated from fresh Heterotrigona itama honey and their antagonistic activities against clinical pathogenic bacteria

Using an anaerobic and culture enrichment method, four strains of lactic acid bacteria (LAB) viz. Sy-1, Sy-2, Sy-3 and Sy-4 were isolated from fresh stingless bee Heterotrigona itama (Family: Apidae, Tribe: Meliponini, Genus: Trigona) honey collected from four geographical localities of Malaysia. Phylogenetic and comparative analyses of conserved region by 16S rRNA gene profiling identified strain Sy-1 being closely related to the genus Lactobacillus (>91%) but exhibited low level strains kinship to other known species within the genus. It is probable that strain Sy-1 is a novel species of the genus Lactobacillus. Conversely, strains Sy-2, Sy-3 and Sy-4 were phylogenetically located in the Fructobacillus fructosus subcluster with sequence similarities of 98, 96 and 95%, respectively. Fructobacillus fructosus was the dominant LAB following its isolation in three out of the four honey samples despite their different geographical origins. API 50 CHL test revealed the strains could proficiently utilize a wide range of carbohydrates, with fructose and glucose being the preferred substrates. All LAB strains possess excellent antagonistic activity against five different clinically pathogenic bacteria, as observed from the zones of inhibition. This study demonstrates the H. itama honey as a reservoir for novel LAB with probiotic properties, envisaging its potential therapeutic role in food.

Integrated air stripping and non-thermal plasma system for the treatment of volatile organic compounds from wastewater: statistical optimization

This study examined the treatment of toluene and m-xylene from wastewater using integrated air stripping and non-thermal plasma (NTP) reactor system. Toluene and m-xylene concentrations, before and...

IRIS: A database application system for diseases identification using FTIR spectroscopy

Infrared information on diseases identification system (IRIS) is an application for diseases identification and analysis by using Fourier transform infrared (FTIR) spectroscopy. This is the preliminary step to gather information from the secondary data which was extracted from recognized various research and scientific paper, which are combined into a single database as in IRIS for our purpose of study. The importance of this database is to examine the fingerprint differences between normal and diseases cell or tissue. With the implementation of this application is it hopes that the diseases identification using FTIR spectroscopy would be more reliable and may assist either physicians, pathologists, or researchers to diagnose the certain type of disease efficiently.

Volatolomics analysis using FTIR spectroscopy for breast cancer identification in vitro

Volatolomics analysis is the technique to analysis the volatile organic compounds (VOCs) from the metabolites. VOCs are released by cancerous cells can be one of the bio-diagnostics techniques to diagnose the cancer. FTIR spectroscopy with White gas cell absorption techniques can analyse and detect the key species from VOCs released. Small amount of VOCs samples can be detected by vacuuming the White gas cell and a low concentration gas also can be detected by employing a long effective optical path-length gas chamber. In this preliminary study, methanol was detected from the VOCs released by breast cancer cells.