As the fundamental unit of soil,aggregates exhibit significant variations in their abilities to adsorb and desorb trace elements,depending on their size.Batch experiments were conducted to investigate the characterist...As the fundamental unit of soil,aggregates exhibit significant variations in their abilities to adsorb and desorb trace elements,depending on their size.Batch experiments were conducted to investigate the characteristics of adsorption and desorption of cadmium(Cd),copper(Cu),and lead(Pb)on and from soil aggregate fractions from three layers of a calcareous soil profile in Changxing County,Zhejiang Prvince,China.The results showed that both Langmuir and Freundlich models successfully described the isothermal adsorption processes of single Cd,Cu,and Pb on different soil aggregates.Additionally,aggregates from the bottom soil layer showed the highest maximum adsorption capacity and required the lowest energy for Cd,Cu,and Pb adsorption compared to aggregates from upper soil layers.The physicochemical properties of soil aggregates were found to govern the adsorption and desorption processes of heavy metals rather than the aggregate size,wherein the contents of iron/aluminum oxides and organic matter were the most crucial influencing factors.Cadmium displayed higher mobility than Cu and Pb in different soil aggregates,and the maximum adsorption capacities of the metal ions followed the order of Pb>Cu>Cd,while their desorption rates followed the order of Cd>Cu>Pb.Additionally,the<0.053 mm microaggregates presented the lowest desorption rates for Cd,Cu,and Pb compared to other soil aggregate fractions in each soil layer.Furthermore,the orthogonal experiment results demonstrated that the competitive adsorption between metals occurred on soil aggregates in the ternary heavy metal system,but only the desorption of Pb was significantly affected by the coexistence of Cd and Cu.展开更多
基金financially supported by the National Key Research and Development Program of China(No.2017YFD0800305)。
文摘As the fundamental unit of soil,aggregates exhibit significant variations in their abilities to adsorb and desorb trace elements,depending on their size.Batch experiments were conducted to investigate the characteristics of adsorption and desorption of cadmium(Cd),copper(Cu),and lead(Pb)on and from soil aggregate fractions from three layers of a calcareous soil profile in Changxing County,Zhejiang Prvince,China.The results showed that both Langmuir and Freundlich models successfully described the isothermal adsorption processes of single Cd,Cu,and Pb on different soil aggregates.Additionally,aggregates from the bottom soil layer showed the highest maximum adsorption capacity and required the lowest energy for Cd,Cu,and Pb adsorption compared to aggregates from upper soil layers.The physicochemical properties of soil aggregates were found to govern the adsorption and desorption processes of heavy metals rather than the aggregate size,wherein the contents of iron/aluminum oxides and organic matter were the most crucial influencing factors.Cadmium displayed higher mobility than Cu and Pb in different soil aggregates,and the maximum adsorption capacities of the metal ions followed the order of Pb>Cu>Cd,while their desorption rates followed the order of Cd>Cu>Pb.Additionally,the<0.053 mm microaggregates presented the lowest desorption rates for Cd,Cu,and Pb compared to other soil aggregate fractions in each soil layer.Furthermore,the orthogonal experiment results demonstrated that the competitive adsorption between metals occurred on soil aggregates in the ternary heavy metal system,but only the desorption of Pb was significantly affected by the coexistence of Cd and Cu.
