RESUMEN
A new one-pot synthesis method optimized by a 23 experimental design was developed to prepare a biosorbent, sugarcane bagasse cellulose succinate pyromellitate (SBSPy), for the removal of Cu(II) and Zn(II) from single-component aqueous solutions, in batch and continuous modes. The bi-functionalization of the biosorbent with ligands of different chemical structures increased its selectivity, improving its performance for removing pollutants from contaminated water. The succinate moiety favored Cu(II) adsorption, while the pyromellitate moiety favored Zn(II) adsorption. Sugarcane bagasse (SB) and SBSPy were characterized using several techniques. Analysis by 13C Multi-CP SS NMR and FTIR revealed the best order of addition of each anhydride that maximized the chemical modification of SB. The maximum adsorption capacities of SBSPy for Cu(II) and Zn(II), in batch mode, were 1.19 and 0.95 mmol g-1, respectively. Homogeneous surface diffusion, intraparticle diffusion, and Boyd models were used to determine the steps involved in the adsorption process. Isothermal titration calorimetry was used to assess changes in enthalpy of adsorption as a function of SBSPy surface coverage. Fixed-bed column adsorption of Cu(II) and Zn(II) was performed in three cycles, showing that SBSPy has potential to be used in water treatment. Breakthrough curves were well fitted by the Thomas and Bohart-Adams models.
Asunto(s)
Saccharum , Contaminantes Químicos del Agua , Purificación del Agua , Adsorción , Celulosa/química , Concentración de Iones de Hidrógeno , Iones , Cinética , Saccharum/química , Ácido Succínico , Contaminantes Químicos del Agua/análisis , Purificación del Agua/métodos , Zinc/análisisRESUMEN
This paper presents a brief discussion with regard to the fixed-bed modeling results of a recent paper by Li et al. published in this journal.
RESUMEN
Giant squid hydrolysate (GSH) elaborated from different batches from a fishing company was evaluated for cadmium removal. Fixed-bed column packed with iminodiacetic resin as adsorbent was used. GSH solution at different cadmium concentrations were fed in the fixed-bed column and breakthrough curves were evaluated. A high degree of metal removal from the solution was achieved and the saturation point (Ce/C0 ≤ 0.8) was achieved more quickly at higher concentrations of cadmium. The maximum capacity of adsorption (q0) was obtained using the Thomas model, where 1137.4, 860.4, 557.4, and 203.1 mg g-1 were achieved using GSH with concentrations of 48.37, 20.97, 12.13, and 3.26 mg L-1, respectively. Five cycles of desorption of the resin with HCl (1 M) backflow and regeneration with NaOH (0.5 M) were also evaluated, where no significant differences (p-value > 0.05) were observed between each cycle, with an average of 935.9 mg g-1 of qmax. The in-series columns evaluated reached a total efficiency of 90% on average after the third column in GSH with a cadmium concentration of 20.97 mg L-1. This kind of configuration should be considered the best alternative for cadmium removal from GSH. Additionally, the chemical composition of GSH, which was considered a quality parameter, was not affected by cadmium adsorption.