Articles authored by UoM staff

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Browsing Articles authored by UoM staff by Subject "Activated carbon"

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    Dealing with algal toxins and dissolved organics in drinking water
    Ratnayake, N; Manatunge, JMA; Hapuarachchi, DP
    Several types of cyanotoxins found in surface water bodies are recognized as having human health effects, whereas taste and odor affect the palatability of water and give rise to public complaints. Conventional water treatment unit operations may be effective in removing the cyanobacteria cells, but cyanotoxins and dissolved organics are not targeted for removal by them. Special treatment units need to be introduced to deal with these substances and attention paid to the process design as many operational issues may be encountered. We used a water supply project in the Eastern Province of Sri Lanka as a case study to investigate the performance of unit operations in water reatment plants for which the source is shallow surface water sources with high inflows of nutrients. The present case study was designed to evaluate the efficacy of prechlorination, activated carbon adsorption, dissolved air flotation (DAF), filtration and disinfection in removal of cyanotoxins, and taste and odor causing dissolved organic substances from the source water. Raw water quality was evaluated using algal concentration, algal toxin concentration, and chemical oxygen demand. To evaluate the efficacy of treatment operations, the sequence of initial unit operation was changed on each day as with prechlorination and with powdered activated carbon (PAC), with prechlorination and without PAC, without prechlorination and with PAC, and without prechlorination and without PAC. In addition, laboratory analysis was done to obtain adsorption isotherms using three types of different PAC. The primary findings of our study were that PAC was effective in removal of Microcystin and chemical oxygen demand (COD) but needs to be optimized by providing sufficient contact time, and prechlorination does not improve the performance, whereas postchlorination is effective in removing any traces of Microcystin left after PAC. 001: 10.10611 (ASCE)HZ.21S3-SS1S.0000114. © 2012 American Society of Civil Engineers.
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    Effect of activated carbon on the properties of natural rubber latex foams
    Rajakaruna, ARM; Walpalage, S; Perera, DGPM
    Activated carbon used as an adsorber in many industries. In this research work activated carbon (AC) has been incorporated as a filler with natural rubber latex compounds to enhance the odour adsorption property of latex foam products. Incorporation of AC into natural rubber latex (NRL) has not been reported in the literature. A methodology was developed to prepare stable colloidal dispersion of AC and incorporate it into NRL compound without affecting the stability of the NRL compound, fine cell structure of the final foam and physical properties of final foam product. It was found that stable AC dispersion with 36% maximum Total Solid Content (TSQ can be prepared by ball milling for 18 h in the absence of dispersion stabilizer. It has been revealed that up to 2% (on dry weight) dosage of AC dispersion can be incorporated into latex compound without disturbing the fine and continuous cell structure of final foam. The incorporation of AC dispersion into latex rubber foam leads to sorption enhancement of ammonia (NH3). The average sorption percentage of AC filled foam is found to be 9.70% and it was 5.04% for foam sample without incorporating AC.