Simultaneous removal of heavy metals from drinking water by banana, orange and potato peel beads: a study of biosorption kinetics

Abstract

Banana, orange and potato peels (BP, OP and PP, respectively) were immobilised to produce biosorbent beads that were employed for the biosorption of heavy metals from a cocktail solution containing As(V), Cd(II), Cr(VI), Cu(II), Hg(II) and Ni(II) ions. Drinking water conditions were maintained with neutral initial pH and low concentration of the ions. Batch experiments were performed for evaluating the effect of pH in the drinking water range (6.5–8.5). Results showed a significant increase in the biosorption capacity of the beads with respective to the uptake of As and Pb, whereas it decreased significantly for Cd, Cu, Hg and Ni ions at basic pH values. Approximate equilibrium biosorption of Cd, Cu, Hg and Ni was 89–92%, 79–87%, 84% and 71–80% by BP, OP and PP beads. The physisorption-based PFO model was the most suitable for the ions with biosorption capacities closer to the experimental values. BP and OP beads had better biosorption efficiencies relative to PP bead due to the higher surface heterogeneity observed by scanning electron microscopy coupled with energy-dispersive spectroscopy. An increase in the biosorbent concentration from one to ten BP beads significantly increased the biosorption percentage of the ions. The biosorption capacities of Cd, Hg and Ni uptake by one BP bead from a 1 mgL−1 cocktail solution were 3.4 ± 0.0, 5.3 ± 0.1 and 3.0 ± 0.0 mgg−1, respectively. Thus, BP beads were the most effective than for the simultaneous removal of heavy metals from drinking water.

Adsorption of Heavy Metals: Mechanisms, Kinetics, and Applications of Various Adsorbents in Wastewater Remediation—A Review

“…Numerous cheap and non-living plant-based materials [133], including potato peels [134], seed shells [135], coffee husks [136], crude olive stones [137], apple peel bead [138], citrus peels [139], shells of hazelnut and almond [140], chemically modified orange peel [141], banana peels and chemically modified banana peels [142], peels from banana, orange, and potato immobilized on sodium alginate beads [143], physic seed hull [144], rice husk [145], millet and Sorghum vulgare (Guinea corn) husks [146], rice and corn husk biochar [147], peanut husk [35], coconut husk [148], palm fruit fiber [149], neem bark [150], sugarcane bagasse [151], Rosa damascena leaf powder [152], and ajwa date pits [92], watermelon rind [130], etc., have been extensively investigated as prospective heavy metal adsorbents (Table 4). As 2+ : 18.43 [163] AD: adsorbent dose, IC: ion concentration, DHPM: dynamic high-pressure micro fluidization.…”

Biosorption of heavy metal ions from the aqueous solutions using groundnut shell activated carbon: batch adsorption, kinetic and thermodynamic studies

“…Figure 14 depicts the linear plots of the Elovich kinetic model, and the constants (a & b) were computed using the slope and deflection values of the linear plots. This model's fundamental premise is that the chemical adsorption of gases on heterogeneous adsorbent surfaces does not allow for any process (Risha et al, 2021). Table 4 shows the regression values (R 2 ) of the Elovich model, which are shown to be high, confirming the applicability of this kinetic model.…”

Biosorption of crystal violet and methylene blue dyes using coconut shell powder

“…The results showed that for both CV and MB dyes, the Freundlich isotherm provided the best fit, followed by the Langmuir, Temkin, and D-R isotherms. This indicates that the Freundlich isotherm model is more suitable for describing the adsorption process of CV and MB dyes by coconut shell biochar, suggesting a multilayer adsorption with heterogeneous characteristics (Nathan et al, 2021). However, the agreement of R 2 values with the Langmuir, Temkin, and D-R isotherms also indicates that these models can adequately describe the adsorption process with monolayer and heterogeneous adsorption behavior.…”