RESUMO
Background: Dyes are used in many industries. The discharge of colored wastewater and effluents from these industries to receiving water bodies could cause many significant problems such as increasing the toxicity and chemical oxygen demand [COD]. So, these types of wastewater should be appropriately treated. The efficiencies of activated carbon derived from date stone in the removal of methylene blue [MB] from aqueous solutions were assessed in this study.
Material and Methods: In this research that was an experimental study and was done in laboratory scale, the effects of different parameters such as initial pH [2-12], adsorbent dose [0.25-5 mg/L], initial dye concentration [50 -400 mg/L], and contact time [20-430 min] on methylene blue adsorption with activated carbon derived from date stone were evaluated. The reaction isotherm using the appropriate equations was also investigated.
Results: The results showed that dye adsorption with high efficiencies were obtained at pH 8. The evaluation of adsorption isotherm showed that laboratory data was best fit with Langmuir isotherm [R2= 0.998] and maximum adsorption capacity was obtained 478.3 mg/g.
Conclusion: Based on the removal efficiency of used MBconcentrations in this study, we found that activated carbon derived from date stones could be applied as an efficient and inexpensive adsorbent in the removal of dyes from wastewater.
RESUMO
Background: Furfural is a toxic chemical, so, to avoid its effects on humans and the environment, furfural-containing wastewater must be treated with an appropriate method prior to dispose in the environment. In this study, advanced oxidation methods based on ozone was used to removal of various concentrations of furfural in laboratory scale
Material and Methods: This study is an applied research and the required samples was taken in desired times. The effects of single ozonation process [SOP], catalytic ozonation process [COP], and single adsorption on activated carbon [SAP] on furfural removal efficiency in different conditions were studied
Results: In this study, the influence of some important parameters such as pH, activated carbon dosage and reaction time on the efficiency of SOP, SAP and COP was studied. In the case of pH, the results showed that the efficiency of all three processes in very acidic and very alkaline conditions were higher than the other pH. By increasing activated carbon dosages, the removal efficiency was also increased. Finally, the removal efficiency for the processes studied, increased by increasing reaction time
Conclusion: The higher removal efficiency of furfural in acidic conditions can be due to direct and catalytic oxidation of furfural by ozone. Higher efficiency in the alkaline pH may be due to indirect oxidation because of hydroxyl radicals generation. About the effect of reaction time, the removal efficiency of COP indicates that there was a synergistic effect in catalytic ozonation processes. The increase of reaction surfaces available for ozoneactivated carbon-furfural reactions could be the reason of increased efficiency with increasing dosages of activated carbon