The adsorptive characteristics of biochar produced from garden green waste (S-char) and a mixture of food waste and garden green waste (FS-char) were investigated. Adsorption of Cu2+, Zn2+, and Mn2+ onto the two biochars reached equilibrium within 48 hours. The metal adsorption was effectively described by the pseudo-second-order kinetic and Freundlich isotherm models which suggest heterogeneous chemisorption. The initial solution pH influenced adsorption of Zn2+ and Mn2+ but not of Cu2+. Simulation via a surface complexation model showed that the fraction of XOCu+ adsorbed onto biochar was increased with increasing pH until it reached the adsorption maximum at pH 8.5, while the endpoint for the maximum of XOMn+ was higher than pH 12. 相似文献
SUMMARY The ethical and social issues of genetically modified crops as reported by the Nuffield Bioethics Committee are summarised. A critique of their findings is presented. It is argued that the apparent benefits are outweighed by the ecological, social and economic costs, and that the yields of some genetically modified crops are poorer when compared to conventional species. Furthermore, the current regulations are far too lax for consumer protection. There is an urgent need for a critical and disinterested review of the scientific basis of the research. 相似文献