Efficient Removal of Pb(II) from Aqueous Solutions by Using Oil Palm Bio-Waste/MWCNTs Reinforced PVA Hydrogel Composites: Kinetic, Isotherm and Thermodynamic Modeling

Abstract

Polyvinyl alcohol (PVA) hydrogel are still restricted for some applications because their lower mechanical strength and thermal stability. The PVA-based composites are drawing attention for the removal of heavy metals based on their specific functionality in adsorption process. The main objective of this work is to synthesize oil palm bio-waste (OPB)/multiwalled carbon nanotubes (MWCNTs) reinforced PVA hydrogels in the presence of N,N′-methylenebisacrylamide (NMBA) as a crosslinking agent and ammonium persulfate (APS) as an initiator via simple in-situ polymerization technique. The as-prepared reinforced nanocomposites were characterized by FESEM, BET surface area, differential scanning calorimetry (DSC), TGA and FTIR analysis. The possible influence of OPB and MWCNTs on the tensile strength, elongation at break and elastic modulus of the samples were investigated. It was found that reinforced nanocomposites exhibited enhanced mechanical properties as compared to non-reinforced material. The evaluation of reinforced nanocomposites was tested by the removal of Pb(II) aqueous solutions in a batch adsorption system. The pseudo-second-order kinetic model was used to illustrate the adsorption kinetic results and Langmuir isotherm was more suitable to fit the equilibrium results providing maximum adsorption capacities. The evaluation of thermodynamic parameters describes the spontaneous, endothermic and chemisorption adsorption process while activation energy reveals the physical adsorption mechanism. Therefore, the coordination effects among OPB, MWCNTs and PVA polymer hydrogels can produce a promising adsorbent material for wastewater treatment applications.

Pristine and Magnetic Kenaf Fiber Biochar for Cd2+ Adsorption from Aqueous Solution

“…The result of isotherm analysis is shown in Figure S2 and Table S2 (Supplementary file). The maximum R 2 values of the tested isotherms indicated that the model mostly suits the experimental results [2,84]. Comparing the correlation coefficients for the three isotherm models obtained for biochar and magnetic biochar, the most suitable is the Langmuir model.…”

Crosslinked Carboxymethyl Sago Starch/Citric Acid Hydrogel for Sorption of Pb2+, Cu2+, Ni2+ and Zn2+ from Aqueous Solution

“…It clearly showed that the amount of sorbate (metal ions) per weight unit of sorbent increased with increasing the initial concentration of metal ion solution. Al-qudah et al [ 43 ] and Zulfiqar et al [ 44 ] claimed that initial concentration generates a concentration gradient that allows the driving force to overcome the resistance to mass transfer of metal ions between the aqueous and solid. Therefore, the higher the initial concentration of metal ion rises the driving force, the more attraction occurred between actives sites of sorbent and metal ions [ 45 ] increased the sorption capacity of CMSS/CA hydrogel.…”

Efficient and Fast Removal of Oils from Water Surfaces via Highly Oleophilic Polyurethane Composites

“…Synthesis of composite materials employing both synthetic and natural substances is a developing technique and the amount of published research is fast growing [ 27 , 28 , 29 ]. This methodology allows to exploit both the potential of synthetic materials and the cost-effectiveness of natural ones with the aim of improving chemical-physical characteristics [ 30 , 31 , 32 , 33 ]. Polyurethane (PU) foams represent one example of synthetic materials that are widely used for the removal of oils from water, because these polymers possess a large specific area, low density and can be ultralight [ 34 , 35 ].…”