Liu Peiya, Li Yujiao, Wen Qinliang, Dong Changxun, Pan Genxing
College of Sciences, Nanjing Agricultural University, Nanjing 210095, China.
College of Sciences, Nanjing Agricultural University, Nanjing 210095, China.
J Environ Sci (China). 2015 Aug 1;34:100-6. doi: 10.1016/j.jes.2015.02.008. Epub 2015 Jun 3.
Soil aggregates were prepared from a bulk soil collected from paddy soil in the Taihu Lake region and aluminum (Al) dissolution, solution pH changes during copper (Cu(2+)) sorption were investigated with static sorption and magnetic stirring. Kinetics of Cu(2+) sorption and Al dissolution were also studied by magnetic stirring method. No Al dissolution was observed until Cu(2+) sorption was greater than a certain value, which was 632, 450, 601 and 674 mg/kg for sand, clay, silt, and coarse silt fractions, respectively. Aluminum dissolution increased with increasing Cu(2+) sorption and decreasing solution pH. An amount of dissolved Al showed a significant positive correlation with non-specific sorption of Cu(2+) (R(2)>0.97), and it was still good under different pH values (R(2)>0.95). Copper sorption significantly decreased solution pH. The magnitude of solution pH decline increased as Cu(2+) sorption and Al dissolution increased. The sand and clay fraction had a less Al dissolution and pH drop due to the higher ferric oxide, Al oxide and organic matter contents. After sorption reaction for half an hour, the Cu(2+) sorption progress reached more than 90% while the Al dissolution progress was only 40%, and lagged behind the Cu(2+) sorption. It indicated that aluminum dissolution is associated with non-specific sorption.
土壤团聚体由采集自太湖地区水稻土的原状土制备而成，通过静态吸附和磁力搅拌研究了铝（Al）的溶解以及铜（Cu(2+)）吸附过程中溶液pH值的变化。还采用磁力搅拌法研究了Cu(2+)吸附和Al溶解的动力学。在Cu(2+)吸附量大于某一特定值之前未观察到Al溶解，该特定值对于砂、黏土、粉砂和粗粉砂组分分别为632、450、601和674 mg/kg。Al溶解随着Cu(2+)吸附量的增加和溶液pH值的降低而增加。溶解Al的量与Cu(2+)的非特异性吸附呈显著正相关（R(2)>0.97），并且在不同pH值下仍然良好（R(2)>0.95）。Cu吸附显著降低溶液pH值。溶液pH值下降的幅度随着Cu(2+)吸附量和Al溶解量的增加而增大。砂和黏土组分由于较高的氧化铁、氧化铝和有机质含量，Al溶解和pH下降较少。吸附反应半小时后，Cu(2+)吸附进程达到90%以上，而Al溶解进程仅为40%，且滞后于Cu(2+)吸附。这表明铝溶解与非特异性吸附有关。
