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First we survey the scope and level of research activities in nanoparticle technology (NPT) in ASEAN by looking at relevant international journal publications (2006–2012) in terms of absolute numbers (AN), numbers of publications per million population (PMP) and per billion USD GDP (PBG). Obviously, the statistics show that, within ASEAN, the strength of Singapore covers a wide range of nanotechnology fields and applications, including carbon materials, biosensors, bioelectronics, and pharmaceutics. Malaysia places emphasis on alloys & compounds, carbon materials, and separation technology. Thailand’s emphasis is on molecular modeling, carbon materials, and biosensors. When classification is made on the morphology of nanoparticles mentioned in the titles, the topmost are nanotubes (including CNT, SWCNT, MWCNT) at 392 out of 612 (64.1%), followed by generic nanoparticle/nanopowder and nanofiber (including nanowire, nanorods). Next we look closer at 2 nanoparticle R&D organizations in Thailand, namely, CEPT (CU) and NANOTEC together with their alliances. The interest in nanotechnology of SCG (Siam Cement Group), a leading Thai industrial conglomerate, will also be briefly introduced. .

Hydrogel based oil encapsulation was attempted with a ternary system of colloidal chitosan, κ-carrageenan, and carboxymethylcellulose sodium salt (NaCMC). Favourable formulations of this ternary system that caused irreversible sol–gel transition by freezing (cryogelation) were found in this study, and the oil phase that contained a selected model food ingredient (curcumin) was successfully encapsulated in this prepared cryogel matrix. The encapsulation yields were found to vary from ca 89–99%, and the values were influenced by the cooling protocol used during freezing, thereby indicating that the gel formation kinetics was intimately related to the degree of encapsulation. The release behaviours of the ingredient were investigated in aqueous systems. The release curves showed that both a burst release and a first order release were achieved simply by changing the freezing condition. Freezing could modify the gel formation of the present cryogel, and the resulting structural modification evidently controlled the oil encapsulation manner. Prepared cryogels were found to be sensitive to the ambient pH. It was suggested that the ternary system of chitosan, κ-carrageenan, and NaCMC is an interesting matrix for designing controlled release system.

Nanostructured ferrite spinels AFe2O4 (A = Co, Ni, Zn) were successfully synthesized via a co-precipitation method using oxalate salt as a precursor in an anionic surfactant system in combination with a simple calcination process. High crystallinity samples of nanoparticle spinels in a grain size range of 15–100 nm were obtained by varying the calcination temperature (300–700 °C) and time (1–5 h). Their pore sizes were controlled in a range of 3 nm up to a hundred nm by tailoring the calcination conditions. Raising the calcination temperature was found to decrease the Brunauer–Emmett–Teller (BET) surface area, and broaden the pore structure due to enhanced crystal growth and agglomeration of interparticles of spinels. Transmission electron microscopy (TEM) images of ferrite spinels calcined at 300 °C showed mesoporous structures with narrow pore size distribution, and the maximum BET surface area of CoFe2O4, NiFe2O4 and ZnFe2O4 were found at 201 (Co), 315 (Ni), and 273 (Zn) m2 g−1, respectively. The magnetic hysteresis loops of the ferrite spinels at room temperature demonstrated ferromagnetism in CoFe2O4, superparamagnetism–ferromagnetism in NiFe2O4, and paramagnetism in ZnFe2O4. The highest saturation magnetization (Ms), remanent magnetization (Mr), and coercivity (Hc) were obtained from high crystallinity spinels calcined at 700 °C. Nanostructured AFe2O4 with high surface area and mesoporosity promises potentials as novel magnetic catalysts.

Cryogel based encapsulation of curcumin, an herbal extract, was successfully carried out with a ternary system of colloidal chitosan, κ-carrageenan, and carboxymethylcellulose sodium salt. The effects of chitosan concentration, κ-carrageenan/CMC ratio of the polymer suspension and molecular weight of chitosan on the sol–gel formation were investigated. The effects of cooling rate during freeze-drying and oil phase composition on the encapsulation yield and the release behavior of curcumin from the hydrogel were determined. And so were the effects of pH of the phosphate-buffered media and oil phase composition on the swelling of the specimens. The microstructure of the resulting specimens revealed core-shell nanoparticles (i.e. oil droplet for core and cryogel membrane for shell) entrapped in the cryogel matrix. The encapsulation yield for two types of suspensions was in a range of 83.9 to 99.6% when a high-MW chitosan was used. Controlled release of the encapsulated curcumin in an aqueous system could be maintained for 4 days, and the releasable amount of curcumin was in a range of 41.1 to 59.9%. The encapsulation yield as well as the released pattern and releasable amount of curcumin were significantly influenced by the cooling protocol used during freezing. Irrespective of the introduced oil phase composition, controlled release of curcumin was achievable when the cooling rate was sufficiently high at − 2.0 °C/min and, interestingly, either a burst release or a first order release could simply be achieved by changing the freezing condition.

For controlling fugitive dust emitted from stone quarrying plant, the dust collection efficiency of a simple wetted screen with mesh size of 250 μm under various conditions of air velocity and inlet dust concentration was experimentally examined. It has been found that without the water supply the collection efficiency of dried screen ranged only from 4% to 12%. However, the wetted screen with a water flow rate of 810 (cm 3 /sec)/m 2 could provide the collection efficiency which was increased up to 82% depending on the inlet dust concentration. With the shuttering action of water film on the wetted screen, a maximum collection efficiency of 95% could be achieved as long as the water film could be maintained.

Nylon 6/clay nanocomposite films were prepared by melt mixing nylon 6 with organoclay using a twin screw extruder attached to a blown film die. The type of surfactant used in the pretreatment of organoclay was expected to affect the degree of clay dispersion, which would in turn affect the degree of crystallinity, crystalline phase and bulk properties of the polymer composite. Two different surfactants used to treat the surface of montmorillonite clay were trimethyl tallow quaternary ammonium chloride (M3T, a single-chain surfactant) and dimethyl bis (hydrogenated-tallow) ammonium chloride (M2(HT)2, a double-chain surfactant). The addition of the resulting organoclay into nylon 6 was found to enhance the formation of γ-phase and increase the degree of crystallinity and crystallization temperature of the nylon 6. In fact nanocomposite films containing the single-chain surfactant showed a higher degree of clay dispersion in nylon 6 matrix, up to 148% higher stiffness and up to 100% lower oxygen permeability than those films containing the corresponding double-chain surfactant at the same inorganic loadings investigated. As expected, the nanocomposite films exhibited 58% higher stiffness in the machine direction than the transverse direction.

While activated carbon (AC) is widely employed for treating water resources contaminated with hazardous organic compounds, regeneration of AC after saturation has been a concerning issue. Supercritical water oxidation (SCWO) in a batch reactor was used to regenerate two commercial activated carbons (CAL and COCO) saturated with pyridine or phenol. BET surface area, pore volume and pore size distribution of CAL and COCO were characterized before and after their regeneration. Decomposition of pyridine and phenol was examined at 400, 450, 525 8C with the presence or absence of hydrogen peroxide. The SCWO regeneration efficiency was determined from the amount of pyridine or phenol adsorbed and desorbed in successive adsorption-regeneration cycles. Effects of SCWO on adsorption capacity of CAL and COCO were experimentally investigated. With SCWO enhanced by H2O2, adsorbed organic compounds could be converted to carbon dioxide, hydrogen and nitrogen.

A three phase fluidized bed reactor was used to investigate the combined effect of adsorption and oxidation for phenolic wastewater treatment. Aqueous solutions containing 10 mg•L-1 of phenol and ozone were continuously fed co-currently as upward flow into the reactor at constant flow rate of 2 and 1 L•min-1, respectively. The phenolic treatment results in seven cases were compared: (a) O3 only, (b) fresh granular activated carbon (GAC), (c) 1st reused GAC, (d) 2nd reused GAC, (e) fresh GAC enhanced with O3, (f) 1st reused GAC enhanced with O3, and (g) 2nd reused GAC enhanced with O3. The phenolic wastewater was re-circulated through the reactor and its concentration was measured with respect to time. The experimental results revealed that the phenolic degradation using GAC enhanced with O3 provided the best result. The effect of adsorption by activated carbon was stronger than the effect of oxidation by ozone. Fresh GAC could adsorb phenol better than reused GAC. All cases of adsorption on GAC followed the Langmuir isotherm and displayed pseudo second order adsorption kinetics. Finally, a differential equation for the fluidized bed reactor model was used to describe the phenol concentration with respect to time for GAC enhanced with O3. The calculated results agree reasonably well with the experimental results.

A three phase fluidized bed reactor was used to investigate the combined effect of adsorption and oxidation for phenolic wastewater treatment. Aqueous solutions containing 10 mg·L −1 of phenol and ozone were continuously fed co-currently as upward flow into the reactor at constant flow rate of 2 and 1 L·min −1 , respectively. The phenolic treatment results in seven cases were compared: (a) O 3 only, (b) fresh granular activated carbon (GAC), (c) 1st reused GAC, (d) 2nd reused GAC, (e) fresh GAC enhanced with O 3 , (f) 1st reused GAC enhanced with O 3 , and (g) 2nd reused GAC enhanced with O 3 . The phenolic wastewater was re-circulated through the reactor and its concentration was measured with respect to time. The experimental results revealed that the phenolic degradation using GAC enhanced with O 3 provided the best result. The effect of adsorption by activated carbon was stronger than the effect of oxidation by ozone. Fresh GAC could adsorb phenol better than reused GAC. All cases of adsorption on GAC followed the Langmuir isotherm and displayed pseudo second order adsorption kinetics. Finally, a differential equation for the fluidized bed reactor model was used to describe the phenol concentration with respect to time for GAC enhanced with O 3 . The calculated results agree reasonably well with the experimental results.

Performance of metal catalysts to decompose aqueous phenol was experimentally investigated. Comparison of the phenol decomposition rates within three-phase fluidized-bed reactors utilizing only O3, TiO2 deposited on silica beads, metal catalyst (Ni or Co) impregnated on mesoporous carbon beads, or O3 in combination with each catalyst was thoroughly examined. It was found that the use of Co catalyst with the presence of O3 led to the best removal condition which aqueous phenol was completely decomposed within 10 min (k = 0.1944 min−1). In contrast, the use of TiO2 without O3 resulted in the worst decomposition of phenol (k = 0.0066 min−1). Some intermediate products, such as hydroquinone and catechol, were also detected but their final concentrations were negligibly low.

The novel nanocomposites consisting of fluorinated polyimide (PI) films and zinc oxide (ZnO) nanoparticles, from which green light emission was observed, have successfully been prepared. The embedded ZnO nanoparticles in PI films were prepared by adding two separate zinc compounds in poly(amic acid) (PAA) solution followed by thermal curing to convert PAA to PI. The added zinc hexafluoroacetylacetonate dihydrate (Zn(hfac)) and zinc nitrate hexahydrate (Zn(NO3)2), were converted by thermal decomposition to semicrystalline ZnO nanoparticles, which was confirmed by XRD technique. The green light emission of the nanocomposite films irradiated by UV light was caused by the intrinsic defects in ZnO crystallites. The PI films embedded with ZnO from Zn(NO3)2 emitted much higher fluorescent intensity than their counterparts from Zn(hfac). In addition, the Zn(hfac)/PI film was thermally more stable than the Zn(NO3)2/PI one. From TEM images, the size of ZnO nanoparticles in PI films derived from 28 mol% Zn(hfac) was much larger than those from 59 mol% Zn(NO3)2.

A 20 mm-diameter electrical hydrocyclone was developed and tested. The presence of the underflow results in a smaller d50 than the absence of the underflow. Additionally, the higher the feed flow rate, the smaller d50. Effect of central rod diameter and initial pH of suspension on the separation cut size was examined with and without underflows. The d50 decreases with the increase of central rod diameter and initial pH values in both with and without the underflow. The zeta potential of particles increases proportionally with the initial pH of suspension. The electrical potential exhibits a stronger effect when the suspension has a higher pH. The d50 becomes smallest under largest central rod diameter, highest pH and longest slurry collecting box condition operates with the positive electrical potential at side wall in the presence of the underflow. Based on the experimental data, general semi-empirical correlations were proposed and the effect of each parameter on d50 was examined.

A novel electric hydrocyclone is developed and tested. Aqueous suspensions of silica with a median diameter of 754 nm and 0.2% volumetric concentration are tested using a 20-mm-diameter hydrocyclone. The ratios of tested underflow rate to throughput are: 0, 0.1, 0.2 and 0.3. The tested volumetric flow rates are 0.083×10−3, 0.117×10−3 and 0.167×10−3 m3/s (5, 7 and 10 l/min). The conical part of the electric hydrocyclone is connected to a cylindrical dust box having 42 mm diameter. This dust box has a central metal rod cone and a cylindrical metal wall between which the desired 50-volt DC electric potential or no potential is applied. The investigated lengths of the dust box are 53 and 106 mm. The three different conditions investigated are: (a) no applied electric potential, (b) positive potential applied at the central rod side and negative potential at the side wall, and (c) positive potential applied at the side wall and negative potential at the central rod side. In both the absence and presence of the underflow, the hydrocyclone with a long dust box is found to give better classification efficiency than that with a short dust box. Interestingly, the effect of electric potential is reversed with respect to the presence and absence of the underflow. The presence of the underflow unexpectedly increase the 50% particle cut size when electric potential is applied. However, the effect of electric potential is reversed when there is no underflow. The electric potential can reduce the 50% particle cut size by up to 10% compared to the absence of electricity. It is found that condition (c) exhibits a stronger effect than condition (b). As expected, the higher the flow ratio, the smaller the particle cut size becomes. Based on the experimental results, an empirical correlation for the 50% particle cut size has been obtained.