Crystal violet dye removal from aqueous solution by porphyrinic metal organic framework composite

Various pollutants such as dyes following the arrival to ecosystems lead to serious global environmental pollution. Due to global strict regulations, it is obligatory to treat the wastewaters before being discharged into the environment. One of the common, reliable and useful techniques employed for removal of synthetic dyes from industrial effluents is an adsorption process. In this study, the adsorption of crystal violet (CV) was carried out from aqueous solution PCN-224/Sepiolite composite obtained from meso-tetrakis (4-carboxyphenyl) porphyrin (TCPP) with different experimental conditions was investigated. The composition and structure of compounds were characterized by FESEM and XRD methods. The effect of various variables including dye concentration, adsorbent amount and contact time was investigated by batch method. Equilibrium data were evaluated using Langmuir, Friendlich and Tamkin isotherms. The Langmuir model best describes the CV dye adsorption, which shows that the CV dye adsorption on PCN-224/Sepiolite composite is monolayer and homogeneous. The maximum adsorption capacity under optimal conditions (adsorbent: 0.02 g, contact time: 120 min, temperature: 25°C) was 38.17 mg g-1. Kinetic data were analyzed using first-order and second-order equations. The quasi-second-order model showed the best fit for the synthetic studies (R2=0.9985), which indicates that CV adsorption is limited by the chemical adsorption process. Overall, the results show that PCN-224/Sepiolite composite can be used as an efficient adsorbent for the treatment of colored effluents.