Adsorption of Cadmium, Manganese and Lead Ions from Aqueous Solutions Using Spent Coffee Grounds and Biochar Produced by Its Pyrolysis in the Fluidized Bed Reactor

Abstract

The adsorption process of cadmium ions (Cd), manganese ions (Mn) and lead ions (Pb) onto the spent coffee grounds (SCG) and activated spent coffee grounds (biochar, A-SCG) was investigated. The SCG activation was carried out in the pyrolysis process in a fluidized bed reactor. scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) measurements and CHN analysis were used in order to define the differences between biomaterials. In the study the different mass of materials (0.2–0.5 g) and constant heavy metal volume and concentration (20 cm3/100 ppm) were investigated on the adsorption process. In order to describe the sorption parameters the Langmuir, Freundlich and Temkin isotherms were used. The maximum adsorption for biochar reached 22.3 mg/g for Pb ions, 19.6 mg/g for Mn ions and 19.4 mg/g for Cd ions which were noticeably higher than the results obtained for spent coffee grounds which reached 13.6 mg/g for Pb ions, 13.0 mg/g for Mn ions and 11.0 mg/g for Cd ions. Metal ion adsorption on both SCG and A-SCG was best described by the Langmuir model, thus chemisorption was a dominant type of adsorption. Studying the kinetics of the sorption process, one can see that the process is of a chemical nature according to the best fit of the pseudo-second rate order model. The obtained results show that the chosen sorbents can be used for the removal of cadmium, manganese and lead compounds from aqueous solutions with high efficiency.

Facial Synthesis of Adsorbent from Hemicelluloses for Cr(VI) Adsorption

“…As shown in Table 2 , the pseudo-second-order kinetics model with a higher correlation coefficients value (R 2 = 0.96, 0.80) fitted better than the pseudo-first-order kinetics model (R 2 = 0.89, 0.68), suggesting that the adsorption behavior of HTC-NH 2 towards Cr(VI) corresponded to pseudo-second-order kinetics. These results indicated that the adsorption rate of Cr(VI) onto adsorbent was mainly determined by the chemical adsorption process, consistent with the previous results [ 45 , 46 , 47 ]. This is showed that the adsorption capacity of HTC-NH 2 was up to 18.33 mg/g, which is much higher than that of HTC (13.68 mg/g).…”

MWCNT Decorated Rich N-Doped Porous Carbon with Tunable Porosity for CO2 Capture

“…The data of the Redlich–Peterson model presents a higher value of R 2 , implying the monolayer and multi-layer adsorption process between the M/P-0.1-600-2 and CO 2 . In addition, Fick models and linear driving force (LDF) [ 38 ] were also conducted to evaluate the adsorption kinetics of M/P-0.1-600-2, as shown in Figure 5 c. The fitted parameters ( Table S5 ) shows that Fick models possesses a higher R 2 and lower χ 2 coefficient value than that of LDF, indicating that the CO 2 adsorption kinetics of M/P-0.1-600-2 follows the Fick model, suggesting that the physical adsorption plays a major role in the adsorption process [ 39 ]. The regeneration property is significant for solid adsorbents.…”

Pectin/Activated Carbon-Based Porous Microsphere for Pb2+ Adsorption: Characterization and Adsorption Behaviour

“…According to the principle of pseudo-second-order model, it was inferred that the adsorption of Pb 2+ by P/ACs was dominated by chemisorption, similar to the results of Chwastowski et al [ 30 ]. The chemisorption such as some electron transfer or sharing between the Pb 2+ and the adsorbents may be the rate-limiting step [ 31 ]. In addition, when the experimental results were fitted into the intraparticle diffusion, the plot exhibits a multi-linearity relationship ( Figure 5 D).…”