Removal of Organic Pollutants from Wastewater Using Wood Fly Ash as a Low‐Cost Sorbent

In this study, untreated and treated wood fly ash (WA) was used as a low‐cost sorbent in batch sorption tests to investigate the removal of organic pollutants from a real wastewater generated by cleaning/washing of machinery in a wood‐laminate floor industry in Sweden. The experiments focused on the effect of the WA dosage and particle size on the removal efficiency for organic compounds. With a WA dosage of 160 g L^?1 and a particle size less than 1 mm, the reductions of chemical oxygen demand (COD), biologic oxygen demand, and total organic carbon were 37 ± 0.4, 24 ± 0.4, and 30 ± 0.3%, respectively. Pre‐treatment of WA with hot water improved the COD removal efficiency by absorption from 37 ± 0.4 to 42 ± 1.6% when the same dosage (160 g L^?1) was applied. Sorption isotherm and sorption kinetics for COD using untreated WA can be explained by Freundlich isotherm and pseudo‐second‐order kinetic models. Intra‐particle diffusion model indicates that pore diffusion is not the rate‐limiting step for COD removal. Based on the experimental data, WA could be used as an alternative low‐cost sorption media/filter for removal of organic compounds from real industrial wastewater.     

Conifer fossil woods from the Santa Marta Formation (Upper Cretaceous), Brandy Bay,James Ross Island,Antarctica

Conifer fossil woods from the Santonian to lower Campanian Santa Marta Formation are anatomically studied in detail. The wood flora is dominated by conifers, mainly Araucariaceae. Conifer fossil woods represent 84% of the samples (26 of 31) of the assemblage. The remaining samples are dicotyledon woods which are not included in this study. Woods are mostly calcified and preservation is often excellent. Fossil woods include three species of Agathoxylon, Phyllocladoxylon antarcticum, Cupressinoxylon hallei and a new species of Cupressinoxylon, C. rotundum Pujana sp. nov. The conifer-dominated forests are consistent with the pollen and macrofloras previously described from sediments of the same stratigraphic unit. This fossil wood assemblage contributes to understand the floristic changes that took place in the Cretaceous forests.     

中国硅化木的地质特征及其开发利用

硅化木分布于我国新疆、浙江等20余省,规模、数量巨大,颜色绚丽。矿物成分以石英及其变种为主,含10多种微量元素和多种氨基酸,主要形成于侏罗纪、白垩纪。其成因是在有大量树木资源,适宜古气候及丰富的高浓度可溶性S iO2等环境中快速缺氧埋藏综合作用的结果。具有重要的科学、经济价值。