两种植物类囊体膜在纳米ZnO 上的组装和光电性质

用水热合成法在掺氟氧化锡(SnO₂: F, FTO)导电玻璃上合成了ZnO 纳米线并用原子力显微镜(AFM)和扫描电镜(SEM)对其进行了表征。利用LB 膜技术将高等植物菠菜(Spinacia oleracea)和海洋绿藻石莼(Ulva lactuca)的类囊体膜分别固定在纳米ZnO 上组装成光电池, 用太阳能测试系统检测比较了其光电性质。研究表明, 由两种植物的类囊体膜LB 膜组成的光电池都能产生光生电流; 蛋白LB 膜的层数显著影响了光电池的光电转化效率, 随着层数的增加, 光电转化效率大大增加。此外, 石莼类囊体膜组装的光电池光电转化效率明显高于菠菜类囊体膜。     

Chromium speciation and existing natural attenuation conditions in lagoonal and pond sediments in the former chemical plant of Porto-Romano (Albania)

Near the outskirts of the Albanian port of Durres on the Adriatic Coast, at a place called Porto Romano, an old chemical complex has been producing chromate salts for a period of ∼20 years (1972–1993). As a result large quantities of chromite ore processing residue (COPR) waste were released mainly as suspended particles and/or dissolved species in effluents, which settled in a decantation pond area, 200 × 250 m in size, east of the industrial plant. Unfortunately, pollutants were spread out with time. Knowing that chromium mobility and toxicity in natural settings is species dependent, the species characterization has been carried out in different sampling media (pond sediments, lagoonal sediments and water samples). Five pond profiles were sampled within the decantation area up to a depth of ∼1 m, till the underlying Quaternary lagoonal silty-clays were reached. Total Cr content is highly variable with values between 1,130 and 24,409 mg/kg which is clearly higher than the defined local background values for lagoonal silty-clays (198 mg/kg of Cr). Leaching of Cr(VI) especially occurs in the pond sediments, which are low in OC, CEC and clay content, under acidic and neutral pH conditions (e.g. up to ∼2,230 mg/kg Cr(VI) leached from a sample containing a total concentration of Cr 12,200 mg/kg). Moreover, leaching of the Cr(III) occurs only under strictly acidic conditions (maximum 1,144 mg/kg leached from a sample containing a total Cr-concentration of 17,608 mg/kg). In this study also a number of natural attenuation conditions (i.e. reaction with lagoonal clays rich in organic matter and iron as well as isomorphous substitution) have been recognized.