Preparation and characterization of modified rice husks by biological delignification and acetylation for oil spill cleanup.

Cellulose is widely used as an effective sorbent to treat wastewater. Cellulosic sorbents have the advantage of biodegradability, as they are natural plant-based materials, compared with the synthetic materials such as polypropylene (PP) or polyurethane (PU). Among the raw biomass materials used for cellulose production, rice husk is one of the most cost competitive and widely available.

Multilayer Dye Adsorption in Activated Carbons-Facile Approach to Exploit Vacant Sites and Interlayer Charge Interaction.

Altering the textural properties of activated carbons (ACs) via physicochemical techniques to increase their specific surface area and/or to manipulate their pore size is a common practice to enhance their adsorption capacity. Instead, this study proposes the utilization of the vacant sites remaining unoccupied after dye uptake saturation by removing the steric hindrance and same-charge repulsion phenomena via multilayer adsorption. Herein, it has been shown that the adsorption capacity of the fresh AC is a direct function of the dye molecular size.

Aluminosilicate-based adsorbent in equimolar and non-equimolar binary-component heavy metal removal systems.

Cadmium (Cd) and lead (Pb) are toxic heavy metals commonly used in various industries. The simultaneous presence of these metals in wastewater amplifies the toxicity of wastewater and the complexity of the treatment process. This study has investigated the selective behavior of an aluminosilicate-based mesoporous adsorbent.

Combating oil spill problem using plastic waste.

Thermoplastic polymers (such as polypropylene, polyethylene, polyethylene terephthalate (PET) and high density polyethylene (HDPE)) constitute 5-15% of municipal solid waste produced across the world. A huge quantity of plastic waste is disposed of each year and is mostly either discarded in landfills or incinerated. On the other hand, the usage of synthetic polymers as oil sorbents, in particular, polyolefins, including polypropylene (PP), and polyethylene (PE) are the most commonly used oil sorbent materials mainly due to their low cost.

Toxic heavy metal capture using a novel electronic waste-based material-mechanism, modeling and comparison.

In the modern communication era, the disposal of printed circuit boards is ecologically of dire concern on a global scale. The two prevalent methods applied for the disposal of this waste are either incineration or landfilling both of which are viewed with skepticism due to their negative environmental impact. Activation of the nonmetallic fraction of this waste leads to the development of a mesoporous material with highly functional groups which can potentially be applied for heavy metal uptake.

Novel application of the nonmetallic fraction of the recycled printed circuit boards as a toxic heavy metal adsorbent.

Printed circuit boards (PCBs) constitute one of the major sources of toxicity in landfill areas throughout the world. Hence, PCB recycling and separation of its metallic and nonmetallic components has been considered a major ecological breakthrough. Many studies focus on the metallic fraction of the PCBs due to its economic benefits whereas the nonmetallic powder (NMP) has been left isolated.

A comparative study on selective adsorption of metal ions using aminated adsorbents.

It is well-known that chitosan consists of amino groups for the chelation of metal ions while NH2-MCM-41 has excellent adsorption selectivities for metals. This work compares both adsorption capacities and selectivities of chitosan and NH2-MCM-41. It has been found that chitosan has adsorption capacities of 1.

Alteration of xylose reductase coenzyme preference to improve ethanol production by Saccharomyces cerevisiae from high xylose concentrations.

A K270R mutation of xylose reductase (XR) was constructed by site-direct mutagenesis. Fermentation results of the F106X and F106KR strains, which carried wild type XR and K270R respectively, were compared using different substrate concentrations (from 55 to 220 g/L). After 72 h, F106X produced less ethanol than xylitol, while F106KR produced ethanol at a constant yield of 0.

Non-UV germicidal activity of fresh TiO2 and Ag/TiO2.

Fresh TiO2 was found to possess a strong germicidal activity even without UV irradiation. Live Yeast (Saccharomyces cerevisiae) cells in contact with fresh TiO2 were found deformed and dead after 15 min contact. The cause of germicidal activity was discussed from the observed cell deformation, lysis and increased absorption at 1680 cm(-1) in FT-IR spectra of the affected cells, which proved the oxidizing effect of fresh TiO2 to cells.

Non-UV based germicidal activity of metal-doped TiO2 coating on solid surfaces.

A stain-based screening method was developed to screen different catalyst coatings for their germicidal activity. A Baclight dead/live bacteria viability kit (invitrogen, molecular probes) was used for staining the cell. The screening was carried out following a standard procedure.

Development of a glucose-6-phosphate biosensor based on coimmobilized p-hydroxybenzoate hydroxylase and glucose-6-phosphate dehydrogenase.

This work reports the development of an amperometric glucose-6-phosphate biosensor by coimmobilizing p-hydroxybenzoate hydroxylase (HBH) and glucose-6-phosphate dehydrogenase (G6PDH) on a screen-printed electrode. The principle of the determination scheme is as follows: G6PDH catalyzes the specific dehydrogenation of glucose-6-phosphate by consuming NADP(+). The product, NADPH, initiates the irreversible the hydroxylation of p-hydroxybenzoate by HBH in the presence of oxygen to produce 3,4-dihydroxybenzoate, which results in a detectable signal due to its oxidation at the working electrode.

Determination of poly(3-hydroxybutyrate) using a combination of enzyme-based biosensor and alkaline hydrolysis.

The combination of an enzyme-based biosensor and alkaline hydrolysis was developed for the measurement of poly(3-hydroxybutyrate) (PHB). The principle of the determination is based on that the alkaline condition converts PHB to produce its monomer, 3-hydroxybutyrate (3-HB), which generates a detectable current signal by an amperometric biosensor through coupled two-enzyme reactions on an electrode. This method takes less than 40 min, and results in a linear detection range of 0.

A disposable, screen-printed electrode for the amperometric determination of azide based on the immobilization with catalase or tyrosinase.

A disposable, screen-printed electrode based on the immobilization of catalase or tyrosinase was developed to construct biosensors for the amperometric determination of azide. The determination principles for azide by these two methods are based on inhibiting the enzymatic consumption of an electrode-detectable substance (hydrogen peroxide or catechol) on an enzyme-immobilized electrode. Both of these methods show a sensitive detection range and a short measuring time.

Development of an oxygen-rich biosensor using enzymatic reaction.

This work reports a novel strategy for the development of an O2-rich biosensor. The principle is based on an enzymatic reaction between catalase and H2O2 to release O2, thus to increase the O2 amount in the enzyme matrix. This method improves the determination reliability by alleviating the O2 dependence.

Development of a bienzyme system for the electrochemical determination of nitrate in ambient air.

This work reports the development of a bienzyme system consisting of salicylate hydroxylase (SHL) and nitrate reductase (NaR) for the electrochemical determination of nitrate. This method measures the concentration of nitrate directly under ambient air without suffering from oxygen interferences. The determination is based on the detection of NADH consumption, and the principle is as follows: NADH initiates the irreversible decarboxylation and hydroxylation of salicylate by SHL in the presence of oxygen to produce catechol, which results in a detectable signal due to its oxidation at the working electrode; the second enzyme, NaR, in the presence of nitrate, reduced the availability of NADH, and consequently, the current difference after the injection of nitrate is proportional to its concentration.

Biosensor for rapid phosphate monitoring in a sequencing batch reactor (SBR) system.

A thick-film phosphate biosensor based on hydrogel immobilized pyruvate oxidase (POD) has been developed for rapid phosphate process control monitoring in an experimental sequencing batch reactor (SBR) system. We have employed a phosphate biosensor in an off-line monitoring of phosphate concentrations in a bench scale SBR. Measurements with biosensor show a good correlation (r2=0.

Solar photocatalytic thin film cascade reactor for treatment of benzoic acid containing wastewater.

A solar photocatalytic cascade reactor was constructed to study the photocatalytic oxidation of benzoic acid in water under various experimental and weather conditions at HKUST. Nine stainless steel plates coated with TiO(2) catalyst were arranged in a cascade configuration in the reactor. Photolytic degradation and adsorption were confirmed to be insignificant total organic carbon (TOC) removal mechanisms.