Understanding the role of zeolite A-supported Cu and Ag nanospecies in ethylene adsorption

LEGNOVERDE, MARÍA S.; RODRÍGUEZ-ESTUPIÑÁN, PAOLA; GIRALDO, LILIANA; MORENO-PIRAJÁN, JUAN CARLOS; BASALDELLA, ELENA I.

Congreso; 11th World Congresses of Chemical Engineering; 2023

Asociación Argentina de Ingenieros Químicos

The presence of toxic heavy metal ions in wastewater from industrial processes leads to great concern due to the risks it poses to health and the environment. Indeed, heavy metals such as Ni (II), Cd (II) and Co (II) are commonly used in mining industry, metal plating battery manufacturing, welding and alloy manufacturing. These pollutants cannot be degraded and their accumulation in the human body can cause various diseases and disorders. Particularly, cobalt accumulation in the human body can produce lung irritations, diarrhea, pneumonia, dermatitis, hair loss and even death. High levels of cadmium in humans can cause kidney disease, diarrhea, stomach pain and severe vomiting, broken bones and even damage to the immune system. On the other hand, exposure to high amounts of nickel causes gastrointestinal problems and adverse effects on the kidneys, lungs and mucous membranes. In addition, there are high chances of developing cancer in different parts of the body.Different physicochemical methods have been developed for treating wastewater streams contaminated with heavy metals including chemical precipitation, reverse osmosis, filtration methods and adsorption. The adsorption process has been considered a promising method for the removal of toxic metals due to its simplicity, flexibility and high efficiency in industrial applicationsSeveral adsorbents have been used for the removal of heavy metals such as silica, activated carbon, zeolites, bioadsorbents, clays, fly ash, etc. Mesoporous ordered silicas have been widely employed in heavy metal retention due to unique properties such as large pore size, high surface area and pore volume, high hydrothermal and mechanical stability.In this research, the use of SBA-15, SBA-15-NH2 and SBA-15-EDTA as adsorbents was investigated for the removal of heavy metals. The materials were characterized by scanning electron microscopy (SEM), nitrogen adsorption-desorption, Fourier transform infrared spectroscopy (FTIR), thermal analyses and potentiometric titration. The samples SBA-15, SBA-15 -NH2 and SBA-15-EDTA were tested in the simple and competitive adsorption of Co (II), Cd (II) and Ni (II) ions from aqueous solutions. The equilibrium data were analyzed using the Langmuir isotherm by nonlinear regression analysis. The influence of textural and chemical characteristics of the three different silicas on Co (II), Cd (II) and Ni (II) removal was also studied. Adsorption isotherms of Ni, Cd and Co fitted well with Langmuir model, exhibiting high adsorption capacity of 47.7, 31.7 and 27.4 mg of metal/g of SBA-15, 62.9, 46 and 59.7 mg of metal/g of SBA-15-NH2 and 74, 72 and 67.7 mg of metal/g of SBA-15-EDTA, respectively, in simple adsorption tests. In the case of adsorption from binary solutions, both cations compete for the same active sites, a preferential Ni adsorption being shown. A detailed data analysis demonstrated that EDTA functionalization allows the best retention efficiency of all heavy metals from their corresponding aqueous solution.