Facile generation of rod-like PbCl2 crystals from Pb(II) aqueous solutions induced by Aliquat 336 at room temperature

BACKGROUND Lead is one of the frequent contaminants of industrial wastewater. This work presents a novel approach for the removal of lead from aqueous solutions through generation of rod-like PbCl2 crystals induced by Aliquat 336 at room temperature. RESULTS Regular rod-like PbCl2 crystals formation was rapid and the reaction could be described by a second-order kinetic model very well. PbCl2 crystals were obtained when Pb(II) concentration was more than 15 g L-1, but the maximum PbCl2 production was achieved at 60 g L-1 for the solution/Aliquat ratio of 5. Increase of Aliquat 336 volume could increase PbCl2 production, but an optimal volume existed for different Pb(II) solutions. The formation of rod-like PbCl2 was strongly dependent on pH, but the yield of crystals was uncorrelated with pH. The presence of ethanol led to high yields of PbCl2, but the crystal size became smaller. CONCLUSIONS The results indicate that PbCl2 crystals form at the interface of the organic and aqueous phases, and the reaction rate is proportional to the Pb(II) in aqueous phase and Cl- in Aliquat 336. H+ promotes the orientated PbCl2 growth with a rod-like shape. The high yield of PbCl2 crystals with ethanol is due to the increases of interface area. Aliquat 336 can be used as an effective PbCl2 crystals inducer for the removal of lead from wastewaters. © 2017 Society of Chemical Industry