The paper considers the application of waste sorption material utilization and pumpkin seed husks formed during the extraction of heavy metal ions from aqueous solutions, as a combustible additive to clay mixtures in production of the porous ceramics. In this regard, this study evluates the effects of different amounts (2-8%) of the spent sorption material in the charge composition with changes in the physical and mechanical properties of ceramic samples obtained by firing at temperatures of 950-1050 ° C. One finding is that the combustion of the organic additive is accompanied by the formation of voids and the release of gases with the formation of pores in the ceramic piece. Another finding is that all clay mixtures with a combustible additive allow the production of porous ceramics to meet the requirements for compressive strength, porosity, density, water absorption and linear shrinkage. It is recommended using 4 % of combustive additive in order to obtain optimal properties in terms of density and strength. During the testing of the developed porous ceramics for heavy metal leaching, the material does not pose an environmental hazard. Finally, the results of this study are applicable for the construction of internal partitions and household buildings.

The Removal of Ni (II) ions from aqueous solutions by adsorption onto eggshell (ES) was investigated. The sorbent is cheap, widespread and may represent an environmental problem. The main parameters (i.e., solution pH, initial concentration of metal ions, sorbent dose, shaking time and temperature) influencing the sorption process, were examined. The Freundlich and Langmuir were applied. Thermodynamic parameters viz. the change in Gibbs free energy change (DGo), enthalpy (DHo) and entropy (DSo) were also calculated. Under the optimum experimental conditions employed, the removal of ~100% of Ni (II) ions was attained. The procedure was successfully applied to remove Nickel (II) from aqueous and different natural water samples.

The adsorption of malonic acid on the rice bran was studied under various conditions such as temperature, contact time, adsorbent dose and concentration of adsorbate. Batch adsorption experiments were conducted and the result showed that the adsorption was dependent on all these parameters. The adsorption process obeys the Langmuir and Freundlich adsorption isotherms. The adsorption capacity was found to be 1.24 mg/g. The Sorption of malonic acid on the rice bran was rapid during the first 20 minutes and the equilibrium was found to be attained within 50 minutes. Negative values of Gibbs free energy change (DGo), show that the adsorption was feasible and spontaneous and negative values of enthalpy change (DHo), confirm exothermic adsorption. Adsorption of malonic acid on the rice bran was characterized by Fourier transform infrared (FT-IR) spectroscopy.