Chemical Modification of Neem (Azadirachta indica) Biomass as Bioadsorbent for Removal of Pb²⁺ Ion from Aqueous Waste Water

Abstract

In this study, neem biomass (a mixture of neem leaf and bark), obtained from the matured neem tree, which is an eco-friendly and low-cost material was selected as a bioadsorbent to remove lead metal ion (Pb2+) from aqueous solutions. Neem biomass-based bioadsorbent having a carboxylic group was prepared by activation using chemical modification by NaOH and citric acid with a very simple method. The optimal activation conditions were determined as 37 min, 120°C, in 0.73 M citric acid, with a sample/acid ratio of 1/100 (mass/volume). To determine the basic properties such as chemical structure, porosity, and surface properties of the neem biomass (NB) and chemically modified neem biomass (CMNB), they were characterized by BET, FTIR, SEM, XRD, and pHpzc methods. It was observed that activation has improved the adsorption capacity of the NB and also caused a more amorphous structure. The effects of adsorption parameters such as pH (2–7), contact time (10–110 min), initial Pb2+ ion concentration (100–300 g/L), and bioadsorbent dosage (01–1.1 g/L) on percentage removal of Pb2+ ion were studied. Maximum removal of Pb2+ ion (97.29%) was recorded at 0.9 g/L bioadsorbent dosage, 50 min contact time, pH of 6, and initial metal ion concentration of 100 mg/L. Kinetics and isotherm studies showed that the adsorption mechanism of Pb2+ ion using CMNB follows pseudosecond-order while isotherm studies fit with both models but, relatively, Freundlich model better fit having a little higher R 2 = 0.9804 . The outcome specifies that the modified bioadsorbent can be utilized as a good and low-cost alternative for the treatment of effluent containing lead (II) ions in water.

Azadirachta indica (AI) leaf extract coated ZnO-AI nanocore–shell particles for enhanced antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA)

“…Peaks at 1240 cm −1 and 1100 cm −1 may be attributed to stretching vibrations of C-O bonds in the ether and ester groups present in the AI leaves. All these bands indicate the presence of different phytochemicals, such as polyols (phenolic acid and flavonoids), terpenoids and protein compounds in AI leaf extract [37,[39][40][41]. Finally, in the case of ZnO-AI nanocore-shell particles (figure 5(b)), it is observed that all the peaks corresponding to diverse functional groups of phytochemicals (indicated by green colour) coexist alongside the distinctive peaks characterising ZnO NPs (indicated by red colour).…”

Sustainable Bio-Based Adsorbents for Simultaneous and Efficient Removal of Hazardous Dyes from Aqueous Solutions

“…Zeta potential was measured on Zeta-90Plus particle size analyzer (Brookhaven Instruments Corporation, New York, United States) using a suspension of different samples prepared in water. For the PZC analysis, the salt addition method was used [ 42 ]. The UV–Vis spectroscopy analysis was performed using the PerkinElmer UV/VIS LAMBDA 365+ model (Ahemdabad, Gujarat, India) in wavelength scan and absorbance mode.…”

Ability of Deep Eutectic Solvent Modified Oat Straw for Cu(II), Zn(II), and Se(IV) Ions Removal

“…Consequently, Simić et al [1] achieved a 2.23-times higher capacity of corn silk for Cd(II) ion removal after modification with KOH. Neem biomass chemically pretreated with NaOH and citric acid was confirmed as an efficient biosorbent to remove Pb(II) ions from aqueous solutions [7]. However, recently attention has been devoted to deep eutectic solvents (DES) as innovative green solvents for lignocellulose biomass treatment to procure the desired characteristics for potential further application.…”