Synthesis and Characterization of a Chemically-Activated Novel Mesoporous Silica for Cobalt Decontamination from Polluted Water

Sina Matavos-Aramyan,Sadaf Soukhakian

doi:10.12944/cwe.14.2.12

Abstract

Mesoporous silica was synthesized by a chemical process and its efficiency was investigated for removal of cobalt (Co2+) ions from contaminated water in a laboratory scale. The characteristics of synthesized mesoporous were analyzed by SEM/TGA. Optimal conditions were determined for important parameters such as solution pH, the absorbent dose, the initial Co2+ concentration, and contact time by a single-variable method through the batch experiments. The SEM results confirmed the synthesized silica had high porosity with a honeycomb-like structure. The results showed that with an increasing adsorbent dose and contact time to the optimum, the efficiency of Co2+ adsorption increased. However, with increasing concentration of Co2+, the removal efficiency decreased. At optimal contact time (8 h), 85 % of Co2+ was removed. The maximum adsorption efficiency at pH =7, initial Co2+ concentration of 5 ppm, and at the adsorbent dose 0.3 g/50 ml, was 89%. The study of adsorption isotherm and kinetic models showed that the adsorption process followed the Freundlich isotherm (R2 = 0.9359) and the second-order kinetic model (R2=0.999). Therefore, the synthesized mesoporous silica presented a chemical adsorption mechanism for Co2+ removal from aqueous media and can be utilized in wastewater treatment containing divalent heavy metals such as Co2+.

Highlights

IntroductionDue to their inherent toxicity and the ability to accumulate in living tissues, are often hazardous to organisms and environment. They can cause many problems for the health of humans and animals as well as the environment. Cobalt (Co2+)Raazi Environmental Protection Foundation, Shiraz, Iran.Research and Development Department, Division of Chemistry, MATAVOS-ARAMYAN & SOUKHAKIAN, Curr
Heavy metals, due to their inherent toxicity and the ability to accumulate in living tissues, are often hazardous to organisms and environment.1 They can cause many problems for the health of humans and animals as well as the environment.2,3 Cobalt (Co2+)Raazi Environmental Protection Foundation, Shiraz, Iran.Research and Development Department, Division of Chemistry, MATAVOS-ARAMYAN & SOUKHAKIAN, Curr
As can be seen from the image, the synthesized mesoporous silica has a honeycomb-like structure and porous structure. It results in a higher surface area for adsorption of metal ions from aqueous environments29 and was suitable to adsorb divalent heavy metals from aqueous solutions

Summary

Introduction

Due to their inherent toxicity and the ability to accumulate in living tissues, are often hazardous to organisms and environment. They can cause many problems for the health of humans and animals as well as the environment. Cobalt (Co2+)Raazi Environmental Protection Foundation, Shiraz, Iran.Research and Development Department, Division of Chemistry, MATAVOS-ARAMYAN & SOUKHAKIAN, Curr. Due to their inherent toxicity and the ability to accumulate in living tissues, are often hazardous to organisms and environment.. Due to their inherent toxicity and the ability to accumulate in living tissues, are often hazardous to organisms and environment.1 They can cause many problems for the health of humans and animals as well as the environment.. Research and Development Department, Division of Chemistry, MATAVOS-ARAMYAN & SOUKHAKIAN, Curr. World Environ., Vol 14(2) 276-289 (2019) 277 ion is an essential element for metabolic activities in low concentrations and may be effective in regulating pro-oxidants in the blood; in high concentrations, it causes acute effects of lung toxicity and asthma, inflammation of the lungs, and chest tightness.. The International Agency for Research on Cancer (IARC), has identified cobalt as a potential carcinogen, and its maximum level in drinking water is 40 μg/L based on the recommendation of EPA. World Environ., Vol 14(2) 276-289 (2019) 277 ion is an essential element for metabolic activities in low concentrations and may be effective in regulating pro-oxidants in the blood; in high concentrations, it causes acute effects of lung toxicity and asthma, inflammation of the lungs, and chest tightness. The International Agency for Research on Cancer (IARC), has identified cobalt as a potential carcinogen, and its maximum level in drinking water is 40 μg/L based on the recommendation of EPA.

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Results

Conclusion