Novel low-cost composite sorbent for remediating synthetic sanitary landfill leachates: Batch and column study

For effectively treating leachates produced from landfills, both batch and column experiments were designed and successfully implemented to prepare a novel composite sorbent through utilizing the sludge coated with iron oxide (FeO) nanoparticles combined with an equal proportion of organically modified bentonite using Cetyltrimethylammonium bromide (Bt-CB). The combined sorbent was shown to be effective at removing cadmium ions (Cd(II)), dissolved organic components (DOC), and ammonia nitrogen (NH3-N) in model acetogenic leachate with an efficiency of over 85%. The results of the batch and continuous experiments indicated a high reactivity trend towards contaminants in liquid phases. The removal efficacy in the batch tests exceeded 90%. The optimum conditions of dosage, contact time and agitation speed were 5 g/50 mL, 120 min, and 200 rpm, respectively. Measurements were well modeled using Langmuir model and the sorption is regulated by physico-chemical forces. Electric surface complexation and physisorption are main mechanisms in the removal of leachate components. The predictions for one-dimensional physical model, presented a satisfactory simulation for the leachate concentrations. The permeable reactive barrier was tested for contaminant migration restriction, and the result reveal that the environment of a position facing the flow direction may have a significant impact on continuous designs.