Banca de DEFESA: JÉSSYCA EMANUELLA SARAIVA PEREIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : JÉSSYCA EMANUELLA SARAIVA PEREIRA
DATA : 14/02/2017
HORA: 09:00
LOCAL: SALA 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: 76
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 studies were carried out in a batch system, whose effects of pH (3.0 to 10.0), adsorbent concentration (2 to 20 gL-1), particle size (0.6 to 0.075 mm) And the initial concentration of the adsorbate (10 to 150 mgL-1) were evaluated. The results indicated an increase in adsorption capacity at pH values between 3 and 7. After reaching pH equal to 7, it is observed that the adsorption capacity is reduced for both studies. Regarding the evaluation of the variation of the adsorbent concentration, it was observed that for the powder of the cashew leaves the increase of the mass quantity did not affect the removal process, however, for the powder of the leaves of the carnauba it was observed that the Percentage of removal is directly proportional to the mass increase. For both cases studied, a better efficiency was observed when using particles with sizes between 0.106 and 0.075 mm. The initial concentration study for the bioadhesives presented similar behavior. The amount of adsorption increases with the increase in the initial concentration of the ions in solution. The experimental data of the adsorption isotherms performed on the cashew leaf powder best fit the Freundlich model, however, for the carnauba leaf powder the Langmuir model was more adequate. The kinetics of the adsorption process for both adsorbents reached equilibrium in the first few minutes of reaction, the cashew and carnauba powder reached equilibrium in approximately 20 and 2 minutes, respectively. In general, the experimental data better fit the pseudo-second order model for both adsorbents. 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:
Externo à Instituição - DAMILSON FERREIRA DOS SANTOS - UFERSA
Presidente - 1308273 - EDUARDO LINS DE BARROS NETO
Externo ao Programa - 1670497 - HUMBERTO NEVES MAIA DE OLIVEIRA