Biosorption is a property of certain type of inactive, microbial biomass to bind and concentrate heavy metals from even very dilute aqueous solutions. Biomass exhibits this property, acting just as a chemical substance, as an ion exchanger of biological origin. It is particularly the cell wall structure of certain algae that is found responsible for this phenomenon. In these experiments, the rate and extent for removal of copper is subjected to parameters such as pH, initial metal concentration, biosorbent size, contact time, temperature and the ability of the biomass to be regenerated in sorption-desorption experiments. The metal adsorption was found to be rapid within 25 minutes. The maximum copper uptake of 30 mg of copper / g of biomass has been observed, in the following conditions: 100 mg / L, 0.1 g of biomass, pH 4 and at temperature of 25°C. From this study, it was found that copper uptake is increasing with increase in pH, with optimum being pH 4. Copper uptake increases substantially from 0 to 25 minutes. Metal biosorption behaviour of raw seaweed Sargassum in six consecutive sorptiondesorption cycles were also investigated in a packed-bed column, during a continuous removal of copper from a 35 mg/l aqueous solution at pH 4. The sorption and desorption was carried out for an average of 85 and 15 hours, respectively, representing more than 40 days of continuous use of the biosorbent. The weight loss ofbiomass after this time was 13.5%. The column service time decreased from 25 hrs in the first cycle to 10 hrs for the last cycle. / Thesis (M.Sc.)-University of KwaZulu-Natal, 2005.

No periodic patterns of temporal variations in the metal levels in U. lactuca or in other seven common seaweed species from Ping Chau were observed from 1999 to 2000. Cu levels were generally negatively correlated with other metals in seaweeds. / Spore production of U. lactuca was significantly reduced by the elevation of copper and nickel levels in the seaweed samples. The reproductive frequency of U. lactuca generally increased from January and February to the maxima in March and April. Copper, nickel and nitrate levels showed significant negative correlations with these reproductive frequencies. / The metal abundance in 24 seaweeds showed the following trend: Fe > Mn, Zn > Cu, Ni, Pb, Cr > Cd. U. lactuca and Padina australis showed relatively high mean and large range values of metal levels. Principal component analysis summarized the overall metal loadings in these 24 seaweed species. The variations in Pb, Fe, Mn and Cr levels in the seaweeds varied greatly. / There were significant spatial variations of different metal levels in the extensive study of U. lactuca from various intertidal waters in Hong Kong from 1999 to 2001. In general, metal levels in U. lactuca increased from January to March or April and then dropped in the following months. No periodic patterns or temporal trends of variations of metal levels in U. lactuca were found. Different metal levels in U. lactuca were comparatively lower than those in other studies in other countries and in past studies in Hong Kong. / There were significantly differences in various metal levels in different structures of Sargassum hemiphyllum, generally decreased in the following order: receptacles > vesicles > leaves > branches. / This thesis research involves biomonitoring levels of eight metal species (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in seaweed and the effects of these metals on the reproduction of Ulva lactuca. The study started from September 1999 and ended in June 2001, covering 40 intertidal sites in Hong Kong and 24 seaweed species. Environmental data on pH, salinity and nutrient levels (ammonia, nitrite, nitrate and phosphate) in seawater from these sites were also monitored. / Wong Tai Choi Richard. / "April 2005." / Advisers: P. C. K. Cheung; P. O. Ang, Jr. / Source: Dissertation Abstracts International, Volume: 67-01, Section: B, page: 0159. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 371-401). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.