Modification of epoxy groups of poly(hydroxylmethyl methacrylate-co-glycidyl methacrylate) cryogel with H3PO4 as adsorbent for removal of hazardous pollutants

Nylon fiber waste as a prominent adsorbent for Congo red dye removal

In this research nylon fibers wastes (NF) were fabricated into porous sheet using a phase inversion technique to be utilized as an adsorbent materials for Congo red dye (CR). The fabricated sheet denoted as NS was characterized using FTIR and XRD. The surface studies of the adsorbent materials using SEM and BET analysis reveals a highly pores structure with an average pore volume 0.61 cc/g and BET surface area of 767 m2/g. The adsorption studies of fabricated NS were employed into CR at different parameters as pH, effect of time and dye concentration. The adsorption isotherm and kinetic studies were more fit to Langmuir and pseudo second order models. The maximum adsorption capacity qmax reached 188 mg/g with removal percentage of 95 for CR concentration of 400 mg/L at pH 6 and 0.025 g NS dose for 10 ml CR solution. The regeneration study reveals a prominent adsorption behavior of NS with removal % of 88.6 for CR (300 mg/L) after four adsorption desorption cycles. Effect of incorporation of NaonFil Clay to NS was studied using Response Surface Methodology (RSM) modeling and reveals that 98.4% removal of CR could be achieved by using 19.35% wt. of fiber with 8.2 g/L dose and zero clay, thus at a predetermined parameters studies of NanoFil clay embedded into NS, there are no significant effect for %R for CR.

Synthesis and characterizations of super adsorbent hydrogel based on biopolymer, Guar Gum-grafted-Poly (hydroxyethyl methacrylate) (Gg-g-Poly (HEMA)) for the removal of Bismarck brown Y dye from aqueous solution

Chemical modification of guar gum was done by graft copolymerization of monomer hydroxyethyl methacrylate (HEMA) using azobisisobutyronitrile (AIBN) as initiator. Optimal reaction parameters were settled by varying one reaction condition and keeping the other constant. The optimum reaction conditions worked out were solvent system: binary, [H2O] = 15.00 mL, [acetone] = 5.00 mL, [HEMA] = 82.217× 10-2 mol/L, [AIBN] = 3.333 × 10-2 mol/L, reaction time = 3 h, reaction temperature = 60 °C on to 1.00 g guar gum with Pg = 1694.6 and %GE = 68,704.152. Pure guar gum polymer and grafts were analyzed by several physicochemical investigation techniques like FTIR, SEM, XRD, EDX, and swelling studies. Percent swelling of the guar gum polymer and grafts was investigated at pH 2.2, 7.0, 7.4 and 9.4 concerning time. The finest yield of Ps was recorded at pH 9.4 with time 24 h for graft copolymer. Guar gum and grafted samples were explored for the sorption of toxic dye Bismarck brown Y from the aqueous solution with respect to variable contact time, pH, temperature and dye concentration so as to investigate the stimuli responsive sorption behaviour. Graft copolymers showed better results than guar gum with percent dye uptake (Du) of 97.588 % in 24 h contact time, 35 °C temperature, 9.4 pH at 150.00 ppm dye feed concentration as compared to Guar gum which only showed 85.260 % dye uptake at alike dye fed concentration. The kinetic behaviour of the polymeric samples was evaluated by applying many adsorption isotherms and kinetic models. The value of 1/n was between 0 → 1 showing that there was physisorption of the BB dye that took place on the surface of the polymers. Thermodynamics of BB Y adsorption onto hydrogels was investigated concerning the Van't Hoff equation. -∆G° values obtained from the curve proved the spontanity of the process. Within the context of adsorption efficiency, an investigation was conducted to examine the process of sorption of Bismarck brown Y dye from aqueous solutions. The graft copolymers demonstrated remarkable adsorption abilities, achieving a dye uptake (Du) of 97.588 % over a 24-h period at a temperature of 35 °C, pH level of 9.4, and a dye concentration of 150.00 ppm. The raised adsorption capacity was additionally corroborated by the application of several adsorption isotherms and kinetic models, which indicated that physisorption is the prevailing process/mechanism. Additionally, the thermodynamic research, utilising the Van't Hoff equation, validated the spontaneity of the adsorption phenomenon, as evidenced by the presence of a negative ∆G° values. The thermodynamic analysis revealed herein establishes a strong scientific foundation for the effectiveness of adsorbent composed of graft copolymers based on guar gum. The research conclude the efficiency of the guar gum based grafted copolymers for the water remediation as efficient adsorbents. The captured dye can be re-utilised and the hydrogels can be used for the same purpose in number of cycles.

Efficient removal of heavy metal and antibiotics from wastewater by phosphate-modified hydrochar

The preparation, characterization and adsorption performance of the phosphate-modified hydrochar (P-hydrochar) for Pb(II) and ciprofloxacin removal are investigated. Pb(II) and ciprofloxacin adsorption behavior fit well with the Hill model with the adsorption capacity of 119.61 and 98.38 mg/g, respectively. Pb(II) and ciprofloxacin adsorption kinetic process are accurately described by the Pseudo-second-order. Pb(II) and ciprofloxacin have synergy in the binary contaminant system, which reveals that Pb(II) adsorption amount is augmented. While ciprofloxacin adsorption amount is also augmented at low Pb(II) concentration and hindered at high Pb(II) concentration. Pb(II) adsorption mechanisms on P-hydrochar (e.g. precipitation, π-π interaction and complexation) are different from the ciprofloxacin (e.g. hydrogen bonding, pore filling, electrostatic attraction). Pb(II) and ciprofloxacin adsorption process are further analyzed by the density functional theory. The coexisted ions have little influenced on Pb(II) and ciprofloxacin adsorption. P-hydrochar still has large Pb(II) and ciprofloxacin adsorption capacity after five cycles. This result indicates that poplar sawdust waste can be converted into an efficient adsorbent to remove Pb(II) and ciprofloxacin from wastewater,.

Nanocellulose-based polyurethane foam adsorbent for pressure-driven dye-contaminated water purification

Dye-contaminated water has caused a worldwide pollution, which is threatening aquatic organisms and human health. In this work, a pressure-driven foam adsorbent (PFA) was bioinspired from the tapestry turban for purifying the dye-contaminated water. The PFA was prepared using an one-step method from nanocellulose (NC), amino-functionalized ZIF-8 (ZIF-8-NH2), and high resilience polyurethane foam (PUF). It was applied to efficiently remove methyl orange (MO) and crystal violet (CV) dyes from dye-contaminated waste solutions. The maximum adsorption capacity of PFA for MO and CV was 225.9 mg/g (25 °C, pH = 2) and 41.6 mg/g (25 °C, pH = 10), respectively, which were acceptable as compared with the reported works. The dyes could be efficiently removed from various river water samples. After 5 cycles, the removal efficiencies of MO and CV decreased from 92.0% and 85.7% to 84.7% and 76.1%, respectively. Moreover, the PFA relied on pressure-driven force to release the purified water under a low pressure.

One-step in-situ sustainable synthesis of magnetic carbon nanocomposite from corn comb (MCCC): agricultural biomass valorisation for pollutant abatement in wastewater

This study explored a novel, eco-friendly, sustainable, low-cost, and abundantly available corn comb (CC) agricultural biomass waste-derived one-step in-situ synthesis of magnetic carbon (MCCC) as an efficient adsorbent for water decontamination applications. Herein, we developed a robust and easily separable MCCC by carbonization of Fe(NO₃)₃.9H₂O single iron salt-soaked CC at 500 °C for 5 h. The as-synthesized MCCC was confirmed for their physicochemical properties by various characterization techniques viz. scanning electron microscopy (SEM), high-resolution transmission emission microscopy (HR-TEM), energy dispersive X-ray (EDX), thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), surface area measurements by Brunauer-Emmett-Teller (BET) study, Raman analysis, and magnetic behavior by VSM analysis. The adsorption properties of MCCC on prototypical pollutant methylene blue (MB) was monitored depending on the effect of pH, adsorbent dose, contact time, and varying concentrations of MB. Especially, the π-π interactions played important role in the adsorption of MB at acidic pH (pH = 4). The MCCC displayed a maximum uptake capacity of 120.73 ± 0.63 mg/g toward MB. The Langmuir, Freundlich, and Temkin adsorption isotherm models were fitted with determined coefficient (R²) values of 0.99, 0.95, and 0.96 respectively. The kinetics of the adsorption process was well fitted with a pseudo-second-order model (R² = 0.99). Most significantly, the as-designed easily separable, and reusable adsorbent, MCCC was effectively applied for the abatement of pollutants, different kinds of dyes, pesticides, and industrial wastewater samples. The sustainable, affordable, and waste to wealth-based MCCC with a simple synthesis methodology can be fruitfully applicable for environmental remediation and water decontamination.

Enhanced adsorption and recyclability of surface modified hydrophobic silica aerogel with triethoxysilane: removal of cefixime by batch and column mode techniques

Amine modified pumice-derived silica aerogel (AMPDSA) was synthesized and grafted up to 6.52 [Formula: see text] with (3-aminopropyl) triethoxysilane for cefixime antibiotic adsorption. Using Response surface methodology, at the pH of 3, the maximum removal of cefixime of 80.42% for an initial concentration of 3.56 mg L^-1 was achieved at an equilibrium time of 150 min. The compliance of various kinetic and isotherm models for the batch sorption system was corroborated from the correlation coefficient (R²) values. The maximum adsorption capacity of 19.76 mg g^-1 and 49.63 mg g^-1 was calculated for Langmuir and Khan isotherm models, respectively. The removal by fixed-bed column as a function of flow rate, initial cefixime concentration, and bed height was also performed. The maximum adsorption capacity of column with the bed height of 15 cm was found to be 31 mg g^-1 at the flow rate of 10 mL min^-1 for the initial concentration of 20 mg L^-1. The compliance of Thomas model with the column sorption was observed. The characterization using SEM, BET, and XRD was carried out for the virgin and regenerated AMPDSAs. The regeneration experiments confirmed the ability of AMPDSA for its cefixime removal efficiency of 80% up to eight cycles.

Anisotropic Dyes Adsorption by Templated Smectic Nanoporous Polymer Films: Pore Size vs Pore Charges Affecting the Adsorption

Selective 2-dimentional (2D) nanoporous polymer films have been developed by a templating method based on hydrogen-bonding supramolecular liquid crystals (LCs) containing benzoic acid and pyridine groups (6OBA·NC6·C6H). The smectic lamellar...

Selective removal of anionic dyes in single and binary system using Zirconium and iminodiacetic acid modified magnetic peanut husk

A novel adsorbent (PN-Fe₃O₄-IDA-Zr) was developed from the chemical modification of peanut husk (a low cost material) with Fe₃O₄, iminodiacetic acid (IDA) and zirconium (Zr) and its efficacy for the sequestration of wastewater assessed using Alizarin red (AR) and Acid chrome blue K (AK) as model pollutants. To elucidate the characteristics of the formed adsorbent, analytical techniques such as the Bruauner-Emmet-Teller (BET) method, X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffractive spectroscopy (XRD) and vibrating sample magnetometer (VSM) were applied. Results from these studies confirmed the formation of a crystalline mesoporous adsorbent with surface properties which enhanced its usefulness. From the adsorption studies, it was observed that factors such as pH, salts, temperature and contact time influenced the uptake of the anionic dyes. The maximum monolayer capacity of PN-Fe₃O₄-IDA-Zr for AR was 49.4 mg g^-1 (at 313 K) and was well fitted by the Langmuir model with the chemisorption process being the dominant reaction mechanism. In binary systems, PN-Fe₃O₄-IDA-Zr exhibited higher affinity for AR as compared with AK. The significant removal efficiency exhibited by this novel adsorbent as well as other unique features such as easy retrieval and high regeneration promotes its prospects as an adsorbent for practical wastewater remediation processes.