The Effect Of Ph On Removal Of Toxic Metal Ions From Aqueous Solutions Using Composite Sorbent Based On Ti-Ca-Mg Phosphates

Cost-effective and eco-friendly method of novel sorbents for various environmental applications remained a great challenge. In this study, TiCaMg phosphates (TiCaMgP) composite was synthesized through simplified heterogeneous process and utilized as a sorbent for the removal of Pb2+, Cd2+, Co2+, Zn2+ and Cu2+ from aqueous solution. A set of batch experiments were carried out to determine the influence of solution pH on the sorption behavior of the new composite sorbent. Overall findings from batch experiments demonstrated that at low pH values the main mechanism responsible for the heavy metal removal from solutions is metal phosphate precipitation. Increased in pH generally leads to decreased in sorption ability of TiCaMgP and sorption mechanism composed by ion-exchange and surface attraction. Kinetic studies revealed that the overall adsorption rate is controlled by film diffusion, intraparticle diffusion and chemical interaction which is described by the pseudosecond-order model. The adsorption data also matched well with Elovich equation indicating that both sorption and desorption processes influence the kinetics of the heavy metal ions uptake. The sorption process on TiCaMgP is much faster compared with that on well-known sorbents such as calcium-magnesium phosphates and titanium phosphates The obtained results suggest that new TiCaMgP sorbent has promising applicability for the removal of heavy metals from aqueous solution in wide pH range.