Evaluation of adsortive potential of coconut mesocarp in the removal of reactive red dye 195 in aqueous effluents

Dantas Filho, Antonio do Nascimento; Aroucha, Edna Maria Mendes; Leite, Ricardo Henrique de Lima; Santos, Francisco Klebson Gomes dos

doi:10.1590/S1517-707620200004.1152

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Articles • Matéria (Rio J.) 25 (04) • 2020 • https://doi.org/10.1590/S1517-707620200004.1152 copy

Evaluation of adsortive potential of coconut mesocarp in the removal of reactive red dye 195 in aqueous effluents

Avaliação do potencial adsortivo do mesocarpo de coco na remoção de corante vermelho reativo 195 em efluentes aquosos

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

The textile industry produces dye-rich effluents that when released in hydric bodies hamper the penetration of sunlight, impairing photosynthetic processes. Besides that, dyes have been indicated as potentially toxic substances. In general, the processes of removing of these contaminants have been much studied, with the technique of adsorption standing out for its high efficiency, in addition to operational advantages and the possibility of reuse agricultural waste as adsorbents, benefiting the environment and reducing costs. The present work had as objective to study the performance of coconut mesocarp utilized as adsorbent in the bleaching process of synthetic effluent containing 25 g.L^-1 of reactive red 195 dye. The adsorbent were characterized by granulometry, thermogravimetric analysis and zero point charge. Kinetic and balance study was realized, applying kinetic models and adsorption isotherms. The adsorbent exhibited removal efficiency of 89.92 % in 120 min. The maximum adsorption capacity was 24.04 g.g^-1 at 30 °C. The kinetic study showed that the data was better adjusted by an Elovich equation, indicating slow chemisorption. The thermodynamic study exhibited that the adsorption process is exothermic and spontaneous for all the temperatures evaluated.

Keywords
Adsorption; Coconut mesocarp; Dye

KINETIC MODEL	EQUATION	PARAMETERS MODELS	R²
Pseudo-1ª order	$q_{t} = q_{e} (1 - e^{- k_{1} t})$	q_e = 5.05	0.897
Pseudo-1ª order	$q_{t} = q_{e} (1 - e^{- k_{1} t})$	k₁ = 7.54x10^-2	0.897
Pseudo-2ª order	$q_{t} = \frac{k_{2} q_{e}^{2} t}{1 + q_{e} k_{2} t}$	q_e = 5.41	0.968
Pseudo-2ª order	$q_{t} = \frac{k_{2} q_{e}^{2} t}{1 + q_{e} k_{2} t}$	k₂ = 2.06x10^-3	0.968
Intraparticle diffusion	$q_{t} = k_{i d} \sqrt{t} + C$	k_id =0.423	0.468
Intraparticle diffusion	$q_{t} = k_{i d} \sqrt{t} + C$	C = 0.0	0.468
Elovich	$q_{t} = \frac{1}{β} (l n α β + \ln t)$	a = 1.22	0.997
Elovich	$q_{t} = \frac{1}{β} (l n α β + \ln t)$	b = 3.014	0.997
Avrami	$q_{t} = q_{e} (1 - e^{{(- k_{A V} t)}^{n}})$	q_e = 5.032	0.895
		k_AV =1.954
		n =0.039

TEMPERATURE (°C)	LANGMUIR MODEL PARAMETERS			FREUNDLICH MODEL PARAMETERS
TEMPERATURE (°C)	Q_MÁX (mg/g)	K_L (L/mg)	R²	K_F(mg/g)	n	1/n	R²
30	05	018	898	786	669	375	994
40	376	014	890	375	532	395	983
50	210	013	896	130	490	401	978
60	932	0 .012	956	703	327	429	995

ADSORBENT	ADSORBATE	ADSORPTION CAPACITY	REFERENCE
rice husk carbon	acid yellow 36	9 mg.g^-1	Malik (2003)
coconut treeflower carbon	eactive red dye	9 mg.g^-1	Senthilkumaar et al. 2006
coconut coir dust	methylene blu	36 mg.g^-1	Macedo et al. 2006
hermally activated coconutcoir activated carbon	methylene blu	59–20.62 mg.g^-1	Sharma and Uma 2009
hawthorn kernel	methylene blue	5 mg.g^-1	Akköz et al. (2019)
coconut mesocarp	red dye 195	4 mg.g^-1	This work

TEMPERATURE (°C)	ΔG (kJ.mol^-1)	ΔH (kJ.mol^-1)	ΔS (kj.mol.^-1K^-1)
30	-2.58	-13.36	-0.035
40	-2.25
50	-2.03
60	-1.47
40	51
50	94
60	32

Laboratório de Hidrogênio, Coppe - Universidade Federal do Rio de Janeiro, em cooperação com a Associação Brasileira do Hidrogênio, ABH2 Av. Moniz Aragão, 207, 21941-594, Rio de Janeiro, RJ, Brasil, Tel: +55 (21) 3938-8791 - Rio de Janeiro - RJ - Brazil
E-mail: revmateria@gmail.com

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[1] Autor Responsável: Francisco Klebson G. Santos