Activation of waste MDF sawdust charcoal and its reactive dye adsorption characteristics

This paper reports an experimental investigation of converting waste medium density fibreboard (MDF) sawdust into chars and activated carbon using chemical activation and thermal carbonisation processes. The MDF sawdust generated during the production of architectural mouldings was characterised and found to have unique properties in terms of fine particle size and high particle density. It also has a high content of urea formaldehyde resin used as a binder in the manufacturing of MDF board. Direct thermal carbonisation and chemical activation of the sawdust by metal impregnation and acid (phosphoric acid) treatment prior to pyrolysis treatment were carried out. The surface morphology of the raw dust, its chars and activated carbon were examined using scanning electron microscopy (SEM). Adsorptive properties and total pore volume of the materials were also analysed using the BET nitrogen adsorption method. Liquid adsorption of a reactive dye (Levafix Brilliant red E-4BA) by the derived sawdust carbon was investigated in batch isothermal adsorption process and the results compared to adsorption on to a commercial activated carbon (Filtrasorb F400). The MDF sawdust carbon exhibited in general a very low adsorption capacity towards the reactive dye, and physical characterisation of the carbon revealed that the conventional chemical activation and thermal carbonisation process were ineffective in developing a microporous structure in the dust particles. The small size of the powdery dust, the high particle density, and the presence of the urea formaldehyde resin all contributed to the difficulty of developing a proper porous structure during the thermal and chemical activation process. Finally, activation of the dust material in a consolidated form (cylindrical pellet) only achieved very limited improvement in the dye adsorption capacity. This original study, reporting some unexpected outcomes, may serve as a stepping-stone for future investigations of recycle and reuse of the waste MDF sawdust which is becoming an increasing environmental and cost liability. (C) 2004 Elsevier Ltd. All rights reserved.

Utilization of analgesics, sedatives, and pain scores in infants with a prolonged hospitlaization: A prospective descriptive cohort study

Aim
Describe the utilization of analgesic and sedative medications and documentation of pain scores in a cohort of critically ill infants in a neonatal intensive care unit.

Method
A prospective, longitudinal, cohort study of infants with a predicted length of stay =28 days. Dosages and routes of administration of analgesic and sedative medications and documentation of pain scores were collected on a daily basis.

Results
55 infants were enrolled into the study. Oral sucrose was administered to all 55 infants, 51 infants (93%) were administered enteral acetaminophen and 50 (91%) infants were administered morphine during their hospitalization. Sedatives were administered to 42 infants (76%); 36 (65%) were administered chloral hydrate and 32 (58%) were administered intravenous midazolam. With the exception of the first week of admission, when there was highest utilization of opioids and lower use of sucrose, acetaminophen and sedatives, the pattern of administration of analgesic and sedative agents remained relatively constant throughout the hospitalization. Pain scores were documented for 36 (65%) infants during their hospitalisation, however for these 36 infants, pain scores were infrequently recorded.

Conclusion
There was substantial and varied analgesic and sedative use in this cohort of infants, yet infrequent documentation of pain assessment scores. These practices highlight important clinical implications for sick infants requiring careful consideration of pain and distress management.

THE DISTRIBUTION AND UTILIZATION OF ZOSTERA SPECIES IN STRANGFORD LOUGH, NORTHERN-IRELAND

Strangford Lough is a sheltered marine inlet on the east coast of Co. Down, Northern Ireland. The distribution of Zostera in the Lough and its exploitation by wildfowl was investigated. There was an estimated 1100 tonnes (fresh weight) of Zostera in the Lough in October 1991 covering some 6.3 km2 of the northern mudflats and representing some 12% of the total intertidal area of the Lough. This was regarded as peak biomass. By January 1992, Zostera was reduced following grazing by wildfowl and weathering to 20% of the initial biomass as measured in the exclusion experiment. The above-ground and below-ground biomass of Zostera were not equally affected with reduction to 7% and 26%, respectively.

Utilization of organophosphonates by environmental microorganisms

A survey of the utilization by environmental micro-organisms of a range of compounds containing the carbon-phosphorus (C-P) bond was carried out. Elective culture studies indicated that 15 of 19 alkylphosphonates tested served only as a sole source of phosphorus for microbial growth. Their metabolism did not lead to the extracellular release of inorganic phosphate. However, four organophosphonates - phosphonoacetate, phosphonoalanine, 2-aminoethylphosphonate and phosphonomycin - supported microbial growth when supplied as either a phosphorus source or as a carbon and energy source, with near-quantitative inorganic phosphate release. Four of five amino alkylphosphonates tested were also utilized as a nitrogen source in the presence of 1 mmol l(-1) inorganic phosphate. In a subsequent screening programme, 99% of bacterial isolates tested were able to utilize 2-aminoethylphosphonate as a sole phosphorus source, 61% as a nitrogen source, 10% as a source of nitrogen and phosphorus, and 2% as a source of carbon, nitrogen and phosphorus; 2% of isolates used phosphonoalanine as a nitrogen source. These results suggest that the uptake and metabolism of organophosphonates by bacteria is less 'tightly' regulated by phosphorus starvation than has previously been supposed.

Hydrolysis characteristics and kinetics of waste hay biomass as a potential energy crop for fermentable sugars production using autoclave parr reactor system

The use of the organic fraction of municipal solid waste crops has received considerable attention as a sustainable feedstock that can replace fossil fuels for the production of renewable energy. Therefore, municipal bin-waste in the form of hay was investigated as a potential energy crop for fermentable sugars production. Hydrolysis of hay by dilute phosphoric acid was carried out in autoclave parr reactor, where reactor temperature (135-200 degrees c) and acid concentration (2.5-10% (w/w)) were examined. Analysis of the decomposition rate of hemicellulosic biomass was undertaken using HPLC of the reaction products. Xylose production reached a maximum value of 13.5 g/100 g dry mass corresponding to a yield of 67% at the best identified conditions of 2.5 wt% H3PO4, 175 degrees C, 10 min reaction time, and at 5 wt% H3PO4, 150 degrees C, and 5 min reaction time. For glucose, an average yield of 25% was obtained at 5 wt% H3PO4, 175 degrees C and 30 min. Glucose degradation to HMF was achieved at 10 wt% H3PO4 and 200 degrees C. The maximum yield for produced arabinose was an average of 3 g/100 g dry. mass corresponding to 100% of the total possible arabinose. The kinetic study of the acid hydrolysis was also carried out using the Saeman and the Two-fraction models. It was found for both models that the kinetic constants (k) depend on the acid concentration and temperature. For xylose and arabinose it was found that the rate of formation was more favoured than the rate of degradation. By contrast, for glucose it was found that glucose degradation was occurring faster than glucose formation. It can be concluded that dilute phosphoric acid hydrolysis of hay crop is feasible for the production of fermentable sugars which are essential for bioethanol synthesis. 

An overview of waste crime, its characteristics, and the vulnerability of the EU waste sector

While waste is increasingly viewed as a resource to be globally traded, increased regulatory control on waste across Europe has created the conditions where waste crime now operates alongside a legitimate waste sector. Waste crime,is an environmental crime and a form of white-collar crime, which exploits the physical characteristics of waste, the complexity of the collection and downstream infrastructure, and the market opportunities for profit. This paper highlights some of the factors which make the waste sector vulnerable to waste crime. These factors include new legislation and its weak regulatory enforcement, the economics of waste treatment, where legal and safe treatment of waste can be more expensive than illegal operations, the complexity of the waste sector and the different actors who can have some involvement, directly or indirectly, in the movement of illegal wastes, and finally that waste can be hidden or disguised and creates an opportunity for illegal businesses to operate alongside legitimate waste operators. The study also considers waste crime from the perspective of particular waste streams that are often associated with illegal shipment or through illegal treatment and disposal. For each, the nature of the crime which occurs is shown to differ, but for each, vulnerabilities to waste crime are evident. The paper also describes some approaches which can be adopted by regulators and those involved in developing new legislation for identifying where opportunities for waste crime occurs and how to prevent it.

Application of laser radiation for the treatment of waste materials using a photocatalyst

One effective approach is to destroy industrial waste and pollution is the use of a semiconductor photocatalysis system. To date such, photocatalysis systems have employed conventional linear light sources. Initial results from a study of a photocatalysis system incorporating a tripled Nd:YAG laser are reported. The laser light not only played a roll as a light source for activating the photocatalyst(TiO₂), but also destroyed the organic species directly via a photochemical process. The reaction intermediates and changes in their concentrations are monitored using HPLC. The relationship between the power of laser and kinetics of photoreaction are discussed.

Hydroprocessing of waste cooking oil over a dispersed nano catalyst: Kinetics study and temperature effect

The kinetics of hydrodeoxygenation of waste cooking oil (WCO) is investigated with unsupported CoMoS catalysts. A kinetic model is established and a comprehensive analysis of each reaction pathway is carried out. The results show that hydrodecarbonylation/decarboxylation (HDC) routes are the predominant reaction pathways in the elimination of oxygen, with the rate constant three times as high as that of hydrodeoxygenation (HDO). However, the HDC activity of the CoMoS catalyst deactivates due to gradual loss of sulfur from the catalyst. HDO process is insensitive to the sulfur deficiency. The kinetic modeling shows that direct hydrodecarbonylation of fatty acids dominates the HDC routes and, in the HDO route, fatty acids are transferred to aldehydes/alcohols and then to C-18 hydrocarbons, a final product, and the reduction of acids is the rate limiting step. The HDO route via alcohols is dominant over aldehydes due to a significantly higher reaction rate constant. The difference of C-18/C-17 ratio in unsupported and supported catalysts show that a support with Lewis acid sites may play an important role in the selectivity for the hydrodeoxygenation pathways and promoting the final product quality