The presence of accumulated heavy metals in the environment constitutes is a serious threat to human life and the environment due to their toxicity. Cu2+, Pb2+ and Cd2+ are the common metals that tend to accumulate in organisms, causing numerous diseases. Several techniques such as adsorption, extraction, phytoextraction, ultrafiltration, reverse osmosis, electrodialysis, ion-exchange, and membrane processes are proposed for the handling of wastewater pollution and removing heavy metals from industrial wastewater required high energy or special operational requirements. The selection of alternative low-cost materials such as sorbents for the removal of heavy metals has emphasized. Recently and the adsorption method using zeolite is considered to be an appropriate method for wastewater handling because of its cost-effectiveness and simplicity.
The efficiency of zeolite for the removal of three heavy metal Cu2+, Pb2+ and Cd2+ ions from a synthetic solution was considered. These three ions were chosen as abundance more pollutants that are present in industrial wastewaters.
The study indicated the suitability of the zeolite used for the removal of Cu2+, Pb2+ and Cd2+ ions from synthetic wastewater, while considering the economic aspects of wastewater treatment. The adsorbent mass, adsorbent particle size, initial solution pH, initial solution concentration and agitation speed are usually the most influential parameters. The efficiency of heavy metal removal was enhanced with increased initial solution pH, increased agitation speed, increased solution concentration, decreased particle size and greater mass of absorbent. The adsorption is a heterogeneous process as the removal rate of Cu2+, Pb2+ and Cd2+ ions mostly occurred early on, but as the contact time increased, there was a decrease in the level of the effect of the parameters on adsorption and the adsorption process became slower. The recent studies show that precipitation affects the rate of removal and the quantities of heavy metals in solution and the adsorption capacity of zeolite that has been regenerated using NaCl is either the same or it changed slightly. The natural zeolite is promising sorbent due to its availability and its low cost and can substitute effectively the use of activated carbon as adsorbent for the removal of metal cations from wastewater.
