Banca de QUALIFICAÇÃO: JÉSSYCA EMANUELLA SARAIVA PEREIRA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : JÉSSYCA EMANUELLA SARAIVA PEREIRA
DATA : 30/01/2017
HORA: 15:00
LOCAL: SALA DE AULA DO NUPEG
TÍTULO:

"Copper ions biosorption from aqueous solution using cashew (anacardium occidentale L.) leaves powder and carnaúba (copernicia prunifera) leaves powder"

 

 

 

PALAVRAS-CHAVES:

adsorption; cashew leaves powder; carnaúba leaves powder; copper

PÁGINAS: 65
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Química
RESUMO:

Lately, the contamination of water bodies caused by heavy metals has become a serious environmental issue. The discharge of effluents which contain heavy metal ions, even at small concentration, without an adequate treatment damages human beings, fauna, and flora thus this affects the wellness of the entire ecosystem. Therefore, these effluents require certain treatment to lower the ions level to an environmentally acceptable concentration before discharging them into the environment. Additionally, bioadsorbents have been used for the treatment of contaminated effluents as an alternative to conventional methods. They have also been largely studied in recent researches. Hence, this work aims to evaluate the usage of red cashew (anacardium occidentale L) leaves and carnaúba (copernicia prunifera) leaves, in powder form, as adsorbents for copper ions removal from synthetic effluents. The physicochemical properties of both leaves were investigated, using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (FRX), thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FTIR) and physical nitrogen adsorption (BET). The adsorption essays were carried out in a batch system and the effects of pH (3.0 to 10.0), adsorbent mass (0.1 to 0.5g), particle size (0.3 to 0.075 Mm) and initial adsorbate concentration (10 to 150 mgL-1) were evaluated. The results indicated that pH equal to 5.0 was the most efficient condition on removing the Cu ions, for both cases. With regard to the adsorbent mass, it was observed that, for the cashew leaves powder, increasing the mass did not promote significant difference on the removal process. However, on the carnauba leaves powder case, it was noticed that the removal percentage increased with the mass increasing. The best removal results were obtained when the adsorbent mass was equal to 0.5 g. On both cases, the most efficient adsorption results were observed when the particles sizes ranged from 0.106 to 0.075 mm. With reference to the initial adsorbate concentration, the cashew leaves powder removed a higher amount of Cu at higher concentration, whereas the carnauba leaves powder showed the opposite behavior. In other words, the higher copper removal percentage was observed at lower concentration. Mathematical models were used to fit the experimental isotherm data and it was observed that the Freundlich model fitted the cashew leaves powder data better. However, for the carnauba leaves powder case, the Langmuir model presented a better fit. The adsorption kinetics data, for both adsorbents, showed that the multielementary equilibrium was reached in less than one minute. Comparing the adsorbents performance, it was observed that the carnauba leaves powder removed a superior copper ion amount, reaching a removal percentage approximately equal to 82%, whereas, under the same conditions of temperature, initial concentration, adsorbent mass and solution volume, the cashew leaves powder showed a removal percentage approximately equal to 27%. The results showed that both the cashew and carnauba leaves powder present the appropriate features for copper adsorption and they both represent an alternative to traditional effluent treatment processes.

MEMBROS DA BANCA:
Presidente - 1308273 - EDUARDO LINS DE BARROS NETO
Externo ao Programa - 1670497 - HUMBERTO NEVES MAIA DE OLIVEIRA
Externo à Instituição - SHIRLLE KATIA DA SILVA NUNES - UFRN