Application of Amberlite IRA 402 Resin Adsorption and Laccase Treatment for Acid Blue 113 Removal from Aqueous Media

Facile synthesis and ultrastrong adsorption of a novel polyacrylamide-modified diatomite/cerium alginate hybrid aerogel for anionic dyes from aqueous environment

An eco-friendly cationic polyacrylamide (CPAM)-modified diatomite/Ce(III)-crosslinked sodium alginate hybrid aerogel (CPAM-Dia/Ce-SA) was synthesized successfully and characterized by SEM-EDS, XRD, FTIR, UV-Vis and XPS. Adsorption performance, interaction mechanism and reusability of CPAM-Dia/Ce-SA used for the removal of acid blue 113 (AB 113), acid blue 80 (AB 80), acid yellow 117 (AY 117), Congo red (CR) and Direct Green 6 (DG 6) anionic dyes from aqueous media were investigated in detail. The results demonstrate that CPAM-Dia/Ce-SA aerogel is macroscopic polymer hybrid spheres with a particle size of around 1.3 mm, unique undulating mountain-like surface and porous mesostructure, and exhibits outstanding adsorption capacity for anionic dyes and good reusability. The maximum adsorption amounts of AB 113, AB 80, AY 117, CR and DG 6 by CPAM-Dia/Ce-SA were 3008, 1208, 914, 1832 and 1232 mg/g at pH 2.0, 60 min contact time and 25 °C, and corresponding removal efficiency reached individually 97.5, 96.6, 99.7, 99.9 and 98.5 % respectively and were less affected by increasing pH up to 10.0. Dye adsorption behaviour and adsorption processes with spontaneous and exothermic nature were perfectly interpreted by the Langmuir and Pseudo-second-order rate models respectively. Physicochemical and multisite-H-bonding synergies promoted the ultrastrong biosorption of anionic dyes by CPAM-Dia/Ce-SA.

Preparation of Eco-Friendly Chelating Resins and Their Applications for Water Treatment

In the present study, two chelating resins were prepared and used for simultaneous adsorption of toxic metal ions, i.e., Cr³⁺, Mn²⁺, Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, and Pb²⁺ (M^X+). In the first step, chelating resins were prepared starting with styrene-divinylbenzene resin, a strong basic anion exchanger Amberlite IRA 402(Cl^-) with two chelating agents, i.e., tartrazine (TAR) and amido black 10B (AB 10B). Key parameters such as contact time, pH, initial concentration, and stability were evaluated for the obtained chelating resins (IRA 402/TAR and IRA 402/AB 10B). The obtained chelating resins show excellent stability in 2M HCl, 2M NaOH, and also in ethanol (EtOH) medium. The stability of the chelating resins decreased when the combined mixture (2M HCl:EtOH = 2:1) was added. The above-mentioned aspect was more evident for IRA 402/TAR compared to IRA 402/AB 10B. Taking into account the higher stability of the IRA 402/TAR and IRA 402/AB 10B resins, in a second step, adsorption studies were carried out on complex acid effluents polluted with M^X+. The adsorption of M^X+ from an acidic aqueous medium on the chelating resins was evaluated using the ICP-MS method. The following affinity series under competitive analysis for IRA 402/TAR was obtained: Fe³⁺(44 µg/g) > Ni²⁺(39.8 µg/g) > Cd²⁺(34 µg/g) > Cr³⁺(33.2 µg/g) > Pb²⁺(32.7 µg/g) > Cu²⁺ (32.5 µg/g) > Mn²⁺(31 µg/g) > Co²⁺(29 µg/g) > Zn²⁺ (27.5 µg/g). While for IRA 402/AB 10B, the following behavior was observed: Fe³⁺(58 µg/g) > Ni²⁺(43.5 µg/g) > Cd²⁺(43 µg/g) > Cu²⁺(38 µg/g) > Cr³⁺(35 µg/g) > Pb²⁺(34.5 µg/g) > Co²⁺(32.8 µg/g) > Mn²⁺(33 µg/g) > Zn²⁺(32 µg/g), consistent with the decreasing affinity of M^X+ for chelate resin. The chelating resins were characterized using TG, FTIR, and SEM analysis. The obtained results showed that the chelating resins prepared have promising potential for wastewater treatment in the context of the circular economy approach.

Designed Construction of 2D Honeycomb Cationic MOF Materials for Selective Removal of Sulfonic Anionic Dyes

Various carcinogenic dyes in water bodies are difficult to degrade due to their stability to light and oxidants, causing extended pollution. In this study, MOF 1 ({[Co(tib)₂]·(H₂O)₂·SO₄}_n) and MOF 2 ({[Cu(tib)₂]·(H₂O)₂·SO₄}_n) (tib = 1,3,5-tirs(1-imidazolyl)benzene) were synthesized by the solvothermal method. MOFs 1 and 2 were successfully characterized by single-crystal X-ray diffraction (XRD) and powder X-ray diffraction (PXRD). Based on the structural characteristics of MOFs 1 and 2, we designed two cationic MOF material skeletons, namely, MOFs I and II ([Co(tib)₂²⁺]_n and [Cu(tib)₂²⁺]_n), which were obtained by calcination in combination with the thermogravimetric curve to remove the free components in the lattice. As expected, MOFs I and II showed an excellent adsorption effect on sulfonic anionic dyes. Notably, the adsorption capacity of MOF I can reach 2922.8 mg g^-1 for Congo Red (CR) at room temperature (RT). The adsorption process fits the pseudo-second-order kinetic model and Freundlich isotherm model. Moreover, zeta potential tests and quantum chemical calculations indicate that electrostatic interactions and hydrogen bond between the hydroxyl group on the sulfonic acid group and the N atom on the imidazole ring mainly promote the adsorption of CR dyes on MOF I. MOFs I and II are revealed as a promising novel adsorption material to remove hazardous organic aromatic pollutants with high efficiency in future endeavors.

Formation of pH-Responsive Cotton by the Adsorption of Methyl Orange Dye

The interest in pH-sensitive textile sensors is growing in the global market. Due to their low-cost production, mechanical stability, flexibility, air-permeability, washability, and reusability, they are more suitable than electronic sensor systems. The research tailored the pH-sensitive textile by applying the pH indicator methyl orange to the cotton fabric during conventional dyeing. Adsorption of methyl orange dye to cotton fabric is hindered due to electrostatic repulsive forces between dye anions and negatively charged cotton fibre. To overcome this problem, chemical modification of cotton fabric using a commercial product was performed. The pH sensitivity of the dyed fabric was spectrophotometrically evaluated. In addition, the colour fastness of dyed cotton fabric to washing, light, hot pressing and rubbing was investigated according to valid SIST EN ISO standards. The research results show that the pH-responsive cotton fabric was successfully developed. The chemical modification of cotton fabric is crucial for the increased adsorption of methyl orange dye. The halochromic effect was not only perceived spectrophotometrically but also with the naked eye. The developed halochromic cotton fabric showed poor colour fastness to light and good colour fastness to hot pressing and rubbing, while no significant improvement in colour fastness to washing was observed, even though the fabric was after-treated with a cationic fixing agent. Higher adsorption of the methyl orange dye to the cotton fabric during the dyeing process leads to less wastewater pollution after dyeing with unfixed dye and, thus, a reduction in wastewater treatment costs.

New Chelate Resins Prepared with Direct Red 23 for Cd2+, Ni2+, Cu2+ and Pb2+ Removal

In this paper, two chelate resins prepared by a simple procedure were used for the removal of Cd2+, Ni2+, Cu2+, and Pb2+ (M2+) from aqueous solutions. Amberlite IRA 402 strongly basic anion exchange resin in Cl− form (IRA 402 (Cl−) together with Amberlite XAD7HP acrylic ester co-polymer (XAD7HP) were functionalized with chelating agent Direct red 23 (DR 23). The chelate resins (IRA 402-DR 23 and XAD7HP-DR 23) were obtained in batch mode. The influence of interaction time, pH and the initial concentration of DR 23 solution was investigated using UV-Vis spectrometry. The time necessary to reach equilibrium was 90 min for both resins. A negligible effect of adsorption capacity (Qe) was obtained when the DR 23 solution was adjusted at a pH of 2 and 7.9. The Qe of the XAD7HP resin (27 mg DR 23/g) is greater than for IRA 402 (Cl−) (21 mg DR 23/g). The efficiency of chelating resins was checked via M2+ removal determined by the atomic adsorption spectrometry method (AAS). The M2+ removal by the IRA 402-DR 23 and XAD7HP-DR 23 showed that the latter is more efficient for this propose. As a consequence, for divalent ions, the chelated resins followed the selectivity sequence: Cd2+ > Cu2+ > Ni2+ > Pb2+. Additionally, Cd2+, Cu2+ and Ni2+ removal was fitted very well with the Freundlich model in terms of height correlation coefficient (R2), while Pb2+ was best fitted with Langmuir model for IRA 402-DR 23, the Cu2+ removal is described by the Langmuir model, and Cd2+, Ni2+ and Pb2+ removal was found to be in concordance with the Freundlich model for XAD7HP-DR 23. The M2+ elution from the chelate resins was carried out using 2 M HCl. The greater M2+ recovery from chelating resins mass confirmed their sustainability. The chelate resins used before and after M2+ removal by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis were evaluated.

Preparation and Superstrong Adsorption of a Novel La(Ⅲ)-Crosslinked Alginate/Modified Diatomite Macroparticle Composite for Anionic Dyes Removal from Aqueous Solutions

In order to solve the problem of dye pollution of the water environment, a green macroparticle composite (CPAM-Dia/SA-La) as a bioadsorbent was prepared through a sodium alginate (SA) reaction with a polyacrylamide (CPAM)-modified diatomite (Dia) and further La(III) ion crosslinking polymerization, and characterized by various analytical methods. The important preparation and adsorption conditions of the composite were explored by the adsorption of Acid blue 113 (AB 113) and Congo red (CR) dyes. The dye adsorption efficiency was evaluated. The results show that CPAM-Dia/SA-La composite prepared under the optimized conditions displays superstrong adsorption capacities of 2907 and 1578 mg/g for AB 113 and CR and almost 100% removal efficiency within 60 min adsorption time at pH 2.0 and 298 K, and they decrease slightly with the pH increase to 10. The fitting of equilibrium data to the Langmuir model is the best and the adsorption kinetic processes can be expressed by the Pseudo-second-order kinetic model. The adsorption processes are both spontaneous and exothermic. The analysis results of FT-IR and XPS revealed that the superstrong adsorption of CPAM-Dia/SA-La for dyes. The composite adsorbed by the dye can be recycled. CPAM-Dia/SA-La is a promising biosorbent for dye wastewater treatment.

Maize Stalk Obtained after Acid Treatment and Its Use for Simultaneous Removal of Cu2+, Pb2+, Ni2+, Cd2+, Cr3+ and Fe3+

In this research, eco-friendly material represented by maize stalk (MS) obtained after acid treatment was employed for simultaneous removal of Cu²⁺, Pb²⁺, Ni²⁺, Cd²⁺, Cr³⁺ and Fe³⁺ (M^X+) from simulated textile aqueous matrix and tannery wastewater produced by the leather industry. The acid treatment of MS was done with 4 M HCl. The influence of experimental parameters was evaluated in order to optimize the adsorption process for simulated textile matrix. The contact time 10–60 min and initial concentration of 0.5–1 mg/L M^X+ influence were studied by batch method. Additionally, the adsorption data of M^X+ onto MS was fitting by kinetic and isotherm models. The results obtained showed that the 60 min was necessary to reach adsorption equilibrium of the MS. The adsorption capacity of MS was 0.052 mg Cu²⁺/g of MS, 0.024 mg Pb²⁺/g of MS, 0.042 mg Ni²⁺/g of MS, 0.050 mg Cd²⁺/g of MS, 0.056 mg Fe³⁺/g of MS and 0.063 mg Cr³⁺/g of MS at pH = 4.2. The Langmuir model described the adsorption process very well. The MS showed huge selectivity for Cr³⁺ and Fe³⁺ in the presence of Cu²⁺, Pb²⁺, Ni²⁺ and Cd²⁺. The adsorption of M^X+ from liquid phases were analyzed by spectrometric adsorption method (AAS). The solid phases of MS before and after adsorption by TG and SEM analysis were characterized. When MS was used for removal of M^X+ from tannery wastewater, two major issues were investigated: First, the decrease of M^X+ content from highly polluted and difficult to treat tannery wastewaters by improve its quality and in the second part, specific recovery of M^X+ from MS mass increasing the economic efficiency of metals production based on green technology.

Natural and Synthetic Polymers Modified with Acid Blue 113 for Removal of Cr3+, Zn2+ and Mn2+

This research had two stages of development: during the first stage, the purpose of the research was to evaluate the adsorption properties of the natural polymer represented by shredded maize stalk (MS) and by Amberlite XAD7HP (XAD7HP) acrylic resin for removal of toxic diazo Acid Blue 113 (AB 113) dye from aqueous solutions. The AB 113 concentration was evaluated spectrometrically at 565 nm. In the second stage, the stability of MS loaded with AB 113 (MS-AB 113) and of XAD7HP loaded with AB 113 (XAD7HP-AB 113) in acidic medium suggests that impregnated materials can be used for selective removal of metal ions (Cr³⁺, Zn²⁺ and Mn²⁺). The metal ions using atomic absorption spectroscopy method (AAS) were determined. The use of MS-AB 113 ensures a high selectivity of divalent ions while the XAD7HP-AB 113 had excellent affinity for Cr³⁺ in the presence of Zn²⁺ and Mn²⁺. As a consequence, two advanced polymers, i.e., MS-AB 113 and XAD7HP-AB 113 that provide huge capacity for removal of Zn²⁺, Mn²⁺ and Cr³⁺ from acid polluted wastewater were obtained.

Macro-Reticular Ion Exchange Resins for Recovery of Direct Dyes from Spent Dyeing and Soaping Liquors

Dyes are a major class of organic pollutants that are well-known for their harmful impact on aquatic life and humans. Several new strategies for removing colours from industrial and residential effluents have recently emerged, with adsorption being the best option. The current study looked at the recovery of direct dyes from aqueous streams for reuse using macro-reticular ion exchange resins (IERs). The investigation includes dyeing single jersey cotton grey textiles with direct dyes from the Isma dye Company in Kafr El Dawar, Egypt. After centrifuging and separating the supernatant liquid, solutions from thirteen different dyes, produced at an average concentration between the wasted and soaping liquor concentrations, were calculated spectrophotometrically from the first dyeing trials. Kinetic data were well fitted with pseudo-second-order rate kinetics. The amounts of dye retained by the anion exchangers increased with a rise in temperature in the case of Strong Base Resin (SBR) and vice versa for Weak Base Resin (WBR). Batch adsorption experiments with SBR and WBR were conducted for each dye, and both Freundlich and Langmuir isotherms were constructed. It was found that adsorption obeyed both isotherms, that monolayer adsorption took place, and that the dye molecular weight, structure, and solubility, as well as the type of anionic resin used, had varying effects on the extent of absorption. The monolayer sorption capacities Q₀ determined from the Langmuir isotherm model for the strongly and weakly basic anion exchangers were found to be 537.6 and 692 mg/g for Direct Yellow RL, respectively. As a result, Yellow RL exhibited the greatest adsorption on both SBR and WBR. Orange GRLL, Blue 3B, and Congo Red, on the other hand, were the poorest colours absorbed by the IERs, whereas Blue RL demonstrated good adsorption by SBR and accelerated adsorption by WBR. Most of the dyes may be recovered and reused in this manner.