Cheu Peng Leh

Extraction and recovery of methylene blue from industrial wastewater using benzoic acid as an extractant.

Liquid-liquid extraction (LLE) of methylene blue (MB) from industrial wastewater using benzoic acid (extractant) in xylene has been studied at 27 degrees C. The extraction of the dye increased with increasing extractant concentration. The extraction abilities have been studied on benzoic acid concentration in the range of 0.36-5.8x10(-2) M. The distribution ratio of the dye is reasonably high (D=49.5) even in the presence of inorganic salts. Irrespective of the concentration of dye, extraction under optimal conditions was 90-99% after 15 min of phase separation. The extracted dye in the organic phase can be back extracted into sulphuric acid solution. The resultant recovered organic phase can be reused in succeeding extraction of dye with the yield ranging from 99 to 87% after 15 times reused, depending on the concentration of the initial feed solution. Experimental parameters examined were benzoic acid concentration, effect of diluent, effect of pH, effect of initial dye concentration, effect of equilibration time, various stripping agents, aqueous to organic phase ratio in extraction, organic to aqueous phase ratio in stripping and reusability of solvent.

Cellulose nanocrystals isolated from oil palm trunk

In this study cellulose nanocrystals were isolated from oil palm trunk (Elaeis guineensis) using acid hydrolysis method. The morphology and size of the nanocrystals were characterized using scanning electron microscopy and transmission electron microscopy. The results showed that the nanocrystals isolated from raw oil palm trunk (OPT) fibers and hot water treated OPT fibers had an average diameter of 7.67 nm and 7.97 nm and length of 397.03 nm and 361.70 nm, respectively. Fourier Transform Infrared spectroscopy indicated that lignin and hemicellulose contents decreased. It seems that lignin was completely removed from the samples during chemical treatment. Thermogravimetric analysis demonstrated that cellulose nanocrystals after acid hydrolysis had higher thermal stability compared to the raw and hot water treated OPT fibers. The X-ray diffraction analysis increased crystallinity of the samples due to chemical treatment. The crystalline nature of the isolated nanocrystals from raw and hot water treated OPT ranged from 68 to 70%.

Optimisation of soda pulping variables for preparation of dissolving pulps from oil palm fibre.

Summary A water prehydrolysis-soda pulping sequence for the preparation of dissolving pulps from oil palm fibre (empty fruit bunches) was investigated using a response surface methodology (RSM) statistical experiment design. Five response variables of screened yield, Kappa number, α-cellulose, viscosity and ash content were statistically analyzed with respect to the three input variables of pulping temperature (T), time-at-temperature (t) and alkali level (A), while keeping the prehydrolysis conditions constant. Optimum conditions were: T = 161°C, t = 100 min and A= 26.1%. Values predicted by RSM for screened yield, Kappa number, α-cellulose, viscosity and ash content at the optimum are 31.2%, 6.0, 96.9%, 16.1 cps and 0.15%, respectively. These values were experimentally verified and very close agreement between experimental and predicted values was obtained.

Potential of Ceiba pentandra (L.) Gaertn. (kapok fiber) as a resource for second generation bioethanol: effect of various simple pretreatment methods on sugar production.

The importance of bioethanol currently has increased tremendously as it can reduce the total dependency on fossil-fuels, especially gasoline, in the transportation sector. In this study, Ceiba pentandra (kapok fiber) was introduced as a new resource for bioethanol production. The results of chemical composition analysis showed that the cellulose (alpha- and beta-) contents were 50.7%. The glucose composition of the fiber was 59.8%. The high glucose content indicated that kapok fiber is a potential substrate for bioethanol production. However, without a pretreatment, the kapok fiber only yielded 0.8% of reducing sugar by enzymatic hydrolysis. Thus, it is necessary to pre-treat the kapok fiber prior to hydrolysis. Taking into account environmentally friendliness, only simple pretreatments with minimum chemical or energy consumption was considered. It was interesting to see that by adopting merely water, acid and alkaline pretreatments, the yield of reducing sugar was increased to 39.1%, 85.2% and >100%, respectively.

Isolation and characterization of cellulose nanocrystals from parenchyma and vascular bundle of oil palm trunk (Elaeis guineensis).

In this study cellulose nanocrystals were isolated through acid hydrolysis process from parenchyma and vascular bundle of oil palm trunk (Elaeis guineensis). The morphological properties of obtained cellulose nanocrystals were studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The microscopy images showed smoother and cleaner surface of parenchyma cellulose nanocrystals when compared to vascular bundle cellulose nanocrystals. The TEM image shows a higher length and diameter for parenchyma cellulose nanocrystals compared to vascular bundle cellulose nanocrystals. The Fourier transform infrared (FTIR) spectra showed changes in functional groups after acid hydrolysis due to removal of lignin, hemicelluloses and other impurities in both type of cellulose nanocrystals. Crystallinity index of cellulose nanocrystals was observed higher for vascular bundle as compared to parenchyma. Thermogravimetric analysis (TGA) was performed to study the thermal stability of cellulose nanocrystals and it was observed higher for parenchyma cellulose nanocrystals compared to vascular bundle.

Properties of cellulose nanocrystals from oil palm trunk isolated by total chlorine free method.

Cellulose nanocrystals were isolated from oil palm trunk by total chlorine free method. The samples were either water pre-hydrolyzed or non-water pre-hydrolyzed, subjected to soda pulping, acidified and ozone bleached. Cellulose and cellulose nanocrystal (CNC) physical, chemical, thermal properties, and crystallinity index were investigated by composition analysis, scanning electron microscopy, transmission electron microscopy, fourier transform infrared, thermogravimetric analysis and X-ray diffraction. Water pre-hydrolysis reduced lignin (<0.5%) and increased holocellulose (99.6%) of ozone-bleached cellulose. Water pre-hydrolyzed cellulose exhibited surface fibrillation and peeling off after acid hydrolysis process compared to non-fibrillated of non-water pre-hydrolyzed cellulose. Water pre-hydrolysis improved final CNC crystallinity (up to 75%) compared to CNC without water pre-hydrolysis crystallinity (69%). Cellulose degradation was found to occur during ozone bleaching stage but CNC showed an increase in crystallinity after acid hydrolysis. Thus, oil palm trunk CNC can be potentially applied in pharmaceutical, food, medical and nanocomposites.

Potential of Ceiba pentandra (L.) Gaertn. (kapok) fiber as a resource for second generation bioethanol: parametric optimization and comparative study of various pretreatments prior enzymatic saccharification for sugar production.

Various pretreatments on Ceiba pentandra (L.) Gaertn. (kapok) fiber prior to enzymatic hydrolysis for sugar production were optimized in this study. The optimum conditions for water, acid, and alkaline pretreatments were 170°C for 45 min, 120°C for 45 min in 1.0% (v/v) H2SO4 solution and 120°C for 60 min in 2.0% (v/v) NaOH solution, respectively. Among the three pretreatments, the alkaline pretreatment achieved the highest total glucose yield (glucose yield calculated based on the untreated fiber) (38.5%), followed by the water (35.0%) and acid (32.8%) pretreatments. As a result, the relative effectiveness of the pretreatment methods for kapok fiber was verified as alkali>water>acid at the condition stated.

Cellulose Reinforced Biodegradable Polymer Composite Film for Packaging Applications

This chapter provides a broad overview of bionanocomposite film prepared from various biodegradable polymers reinforced with nanocellulose. In nature, biodegradable polymer exhibits relatively weaker properties than the synthetic polymers. Incorporation of cellulose into the biopolymer matrix has improved the mechanical, thermal, and barrier properties of the resulting biopolymer film significantly. This achievement has encouraged their application as packaging material. Since they have a huge potential in the future, further investigation of this composite material is crucial.

Combination of aqueous pre-treatments with oxygen-alkali extraction for the enhancement of kenaf core fibre hydrolysability into fermentable sugars

Kenaf core fibre was introduced for cellulosic alcohol production. Various pre-treatments with and without oxygen-alkali extraction were employed in this study. The effects of pre-treatments on the enzymatic hydrolysability of kenaf core fibre for sugar production were investigated by FTIR and SEM to characterise the chemical structure and examine the morphology of the fibre, respectively. Both characterisation results were supported by chemical composition analysis of biomass. Results showed that the glucose yield of the fibre with a pre-treatment followed by an oxygen-alkali extraction was remarkably higher than that of the counterpart without an oxygen-alkali extraction. Chemical and morphology analyses indicated that the combination of oxygen-alkali extraction with water and acid pre-treatments could increase the fibres saccharification due to large removal of hemicellulose as well as lignin, and severe structural modifications of fibre. Nevertheless, the combination of alkali pre-treatment with oxygen-alkali extraction did not change the chemical composition and surface morphology of the fibre dramatically. [Received: January 3, 2016; Accepted: April 24, 2016]