Engineered Superabsorbent Nanocomposite Reinforced with Cellulose Nanocrystals for Remediation of Basic Dyes: Isotherm, Kinetic, and Thermodynamic Studies

Abstract

In this study, cellulose nanocrystals (CNCs) were produced from pea peels by acid hydrolysis to be used with pectin and acrylic acid (AAc) to form Pectin-PAAc/CNC nanocomposite by γ-irradiation. The structure, morphology, and properties of the nanocomposite were investigated using Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM) techniques. The nanocomposite hydrogel was used for the removal of methylene blue dye (MB) from wastewater. The results revealed that the presence of CNCs in the polymeric matrix enhances the swelling and adsorption properties of Pectin-PAAc/CNC. The optimum adsorbate concentration is 70 mg/L. The kinetic experimental data were fit by pseudo-first-order (PFO), pseudo-second-order (PSO), and Avrami (Avr) kinetic models. It was found that the kinetic models fit the adsorption of MB well where the correlation coefficients of all kinetic models are higher than 0.97. The Avr kinetic model has the lowest ∆qe (normalized standard deviation) value, making it the most suitable one for describing the adsorption kinetics. The adsorption isotherm of MB by Pectin-PAAc follows the Brouers–Sotolongo model while that by Pectin-PAAc/CNC follows the Langmuir isotherm model. The negative values of ∆G confirmed the spontaneous nature of adsorption, and the positive value of ∆H indicated the endothermic nature of the adsorption.

Removal of Methylene Blue from Aqueous Solutions Using a New Natural Lignocellulosic Adsorbent—Raspberry (Rubus idaeus) Leaves Powder

“…Anthropogenic activity is the main cause of environmental pollution and, implicitly, water contamination. Dyes from residual effluents can cause severe adverse toxicological and aesthetic effects on the aquatic environment [ 1 , 2 , 3 , 4 , 5 ].…”

“…It has numerous applications in the textile, tannery, plastics, food, cosmetics, and paper industries. It is also used in the pharmaceutical industry and medical practice (methaemoglobinemia treatment, cyanide poisoning treatment, or as a staining agent) [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. But this dye can also cause various negative effects on human health and the environment.…”

“…In order to remove the dyes (including methylene blue) from aqueous solutions, several different techniques have been applied as follows: coagulation, flocculation, precipitation, membrane processes, chemical oxidation, electrochemical processes, catalytic reduction, photocatalytic degradation, ion exchange, adsorption, microorganism degradation, membrane bioreactors, aerobic, and anaerobic biological treatments [ 1 , 2 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ].…”

“…Adsorption has proven to be a simple, efficient, and economical method that can use a wide variety of synthetic and natural materials as adsorbents [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 21 , 22 , 23 ]. The adsorbent price is a very important factor when deciding the practical applicability of a new adsorbent material.…”

“…The adsorbent price is a very important factor when deciding the practical applicability of a new adsorbent material. An absorbent is considered “low cost” if it is found in large quantities and needs minimal processing before use or if it is a by-product or waste from another activity [ 1 , 4 , 6 , 7 , 8 , 12 , 16 , 17 ]. Thus, various natural materials (clay-minerals, zeolites), bio-adsorbents (algal, bacterial, fungal, various biomasses), and agricultural or industrial wastes (fibers, peals, leaves, barks, fly ashes, sludges) have been used as low-cost adsorbents for the treatment of dye-containing wastewaters [ 2 , 4 , 7 , 8 , 9 , 12 , 16 , 20 ].…”