Moringa oleifera seed husks for methylene blue dye adsorption: kinetic, equilibrium, and thermodynamic analyses
Revista Ambiente E Água
Moringa oleifera seed husks for methylene blue dye adsorption: kinetic, equilibrium, and thermodynamic analyses
Autor Correspondente: Adriano Gonçalves dos Reis | [email protected]
Palavras-chave: agricultural wastes; low-cost adsorbent; physisorption
Resumos Cadastrados
Resumo Português:
Cas·cas de sem·entes de M. oleifera (H-MO) fora·m usadas com·o adsorve·nte para remo·ver o coran·te az·ul de metile·no (MB) de uma solu·ção aqu·osa. O adsorve·nte foi caracte·rizado por ME·V, ED·S, DRX, FT·IR, B·ET e pH·PCZ. Para aval·iar a capacid·ade de adsor·ção, foi ana·lisada a influ·ência do pH, ciné·tica, isoter·mas e propr·iedades termo·dinâmicas. Técnic·as de caracter·ização indic·aram que a H-MO poss·ui caracter·ísticas morfológ·icas hetero·gêneas com á·rea supe·rficial espe·cífica de 3,24 m2 g-1, co·mposta prin·cipalmente por celu·lose distr·ibuída em estr·utura am·orfa. A adso·rção de MB foi favo·rável em va·lores de pH supe·riores a pHP·CZ de 6,6, utili·zando uma dosa·gem de ads·orvente de 1,0 g L-1. O equ·ilíbrio foi alca·nçado nos prim·eiros 240 min, e o mode·lo de pseu·do seg·unda or·dem foi adequa·do para desc·rever os dad·os cin·éticos. Fre·undlich foi o mo·delo mais ade·quado para des·crever as curvas isot·érmicas, preve·ndo uma cap·acidade máx·ima de ads·orção de 122,7 mg g-1 a 24°C, supe·rior a ou·tros adsor·ventes nat·urais. O pro·cesso de adsor·ção foi esp·ontâneo e exoté·rmico, indi·cando que temper·aturas mais ba·ixas favor·ecem a adsor·ção e que ela é con·trolada por for·ças físi·cas. Os d·ados aprese·ntados indi·cam que o M·B tem· po·tencial para ser tr·atado com suc·esso pelas ca·scas de semen·tes de M. oleif·era, um adsorvente ecol·ogicamente favo·rável e de ba·ixo custo.
Palavras-chave: adsorventes de baixo custo; fisissorção; resíduos agrícolas
Resumo Inglês:
M. ole·ifera se·ed hu·sks (H-M·O) w·ere u·sed as adsorbent for the removal of methylene blue (MB) dye from an aqueous solution. The ads·orbent was char·acterized by SE·M, ED·X, X·RD, F·TIR, B·ET, and p·HPZC. To evaluate adsorption capacity, the influences of p·H, kinetics, isotherms, and thermodynamic prop·erties were anal·yzed. Characteri·zation tech·niques indic·ated that H-MO has het·erogeneous morp·hological charac·teristics wi·th a spe·cific sur·face a·rea of 3.24 m2 g-1, mai·nly comp·osed of ce·llulose distr·ibuted in an amor·phous stru·cture. MB adsorption was favorable at pH values higher than pHPZC of 6.6, using an adsorbent dosage of 1.0 g L-1. Equilibrium was achieved in the first 240 min, and the pseudo-second-order model was suitable for describing the kinetic data. Freu·ndlich was the mo·st adeq·uate model for descri·bing the isoth·erm cur·ves, pred·icting a max·imum adsor·ption capa·city of 122.7 mg g-1 at 24°C, hig·her tha·n oth·er natu·ral ad·sorbents. The ads·orption proc·ess w·as spo·ntaneous and exoth·ermic, indic·ating that lo·wer temper·atures fav·or the ad·sorption and th·at it is cont·rolled by p·hysical fo·rces. The da·ta presen·ted indic·ate the M·B has t·he pot·ential to be succ·essfully trea·ted by the eco-fr·iendly and l·ow-cost ads·orbent M. oleif·era seed h·usks.
Keywords: agricultural wastes; low-cost adsorbent; physisorption
Resumo Espanhol:
M. ole·ifera se·ed hu·sks (H-M·O) w·ere u·sed as adsorbent for the removal of methylene blue (MB) dye from an aqueous solution. The ads·orbent was char·acterized by SE·M, ED·X, X·RD, F·TIR, B·ET, and p·HPZC. To evaluate adsorption capacity, the influences of p·H, kinetics, isotherms, and thermodynamic prop·erties were anal·yzed. Characteri·zation tech·niques indic·ated that H-MO has het·erogeneous morp·hological charac·teristics wi·th a spe·cific sur·face a·rea of 3.24 m2 g-1, mai·nly comp·osed of ce·llulose distr·ibuted in an amor·phous stru·cture. MB adsorption was favorable at pH values higher than pHPZC of 6.6, using an adsorbent dosage of 1.0 g L-1. Equilibrium was achieved in the first 240 min, and the pseudo-second-order model was suitable for describing the kinetic data. Freu·ndlich was the mo·st adeq·uate model for descri·bing the isoth·erm cur·ves, pred·icting a max·imum adsor·ption capa·city of 122.7 mg g-1 at 24°C, hig·her tha·n oth·er natu·ral ad·sorbents. The ads·orption proc·ess w·as spo·ntaneous and exoth·ermic, indic·ating that lo·wer temper·atures fav·or the ad·sorption and th·at it is cont·rolled by p·hysical fo·rces. The da·ta presen·ted indic·ate the M·B has t·he pot·ential to be succ·essfully trea·ted by the eco-fr·iendly and l·ow-cost ads·orbent M. oleif·era seed h·usks.
Keywords: agricultural wastes; low-cost adsorbent; physisorption
