Removal of heavy metals from waste water using a hybrid membrane process

Abstract

CC-BY 4.0 License requiring that the original work has been properly cited.Soil and water pollution by heavy metals is currently a very important problem in environmental and other sectors. The origin of metals in water may be of either natural character (erosion of rocks and sediments, leaching of mineral resources) or anthropogenic character (mining and extraction of metals, industry, agriculture, etc.) (Martins et al. 2010). Many heavy metals, such as Pb, Cd, Cu, Zn, etc., are the most polluting factors in industrial wastewater and may get into the ground water. Subsequently they are bio-accumulated in living organisms and cause various diseases and disorders (Jamil et al. 2010). These problems need to be responded by developing new and more efficient methods for wastewater treatment (Martins et al. 2010). In practice several methods are used for removal of heavy metals from water. One of the promising methods for the removal of metal ions from water is a hybrid membrane processes. This method includes two processes -adsorption of metal ions on the natural zeolite and microfiltration of zeolite suspension through ceramic membrane. Experiments were carried out using model solutions In the experiments zeolite from Nižný Hrabovec localization (Zeocem JSC Bystré), Slovakia was used. Zeolite is mainly composed of mineral clinoptilolite (84%), other mineral are cristobalite (8%), clay (4%) and plagioclase (3-4%). Its structure is formed by three-dimensional network. Clinoptilolite is composed from silicate tetra- were prepared from each of the chemicals. The solutions were shaken with 1 g of zeolite in 100 ml PET flasks on a shaker for 2.5 hours at 25°C and 220 rpm. The amounts of metals (Cu or Zn) in solutions were measured after stabilization, filtration and required dilution by AAS. The equilibrium between the concentration in solution and the adsorbed substance was evaluated using Langmuir, Freundlich and Redlich-Peterson models. According to the results of the adsorption experiments zeolite adsorbed of both the nitrates ions (Cu , respectively) less. Due to better adsorption capacities of zeolite for ions derived from nitrates, further experiments were made from chemicals Cu(NO 3 ) 2 •3H 2 O and Zn(NO 3 ) 2 •6H 2 O.

Removal of heavy metals and pollutants by membrane adsorption techniques

“…It was also reported that the passage of ions through nanotubes was related to the diameter of the BN nanotubes. Sabo et al (2015) described a hybrid membrane processes for the removal of metal ions from water. This method includes two processes: adsorption of metal ions on the natural zeolite and microfiltration of zeolite suspension through ceramic membrane.…”