A simple method for removal of toxic dyes such as brilliant green and acid red from the aquatic environment using halloysite nanoclay

Industrial dye absorption and elimination from aqueous solutions through bio-composite construction of an organic framework encased in food-grade algae and alginate: Adsorption isotherm, kinetics, thermodynamics, and optimization by Box-Behnken design

A potential bio-adsorbent material for removing Rhodamine B (RB) from aqueous solution is Ru-MOF@FGA/CA beads. The adsorption capability of the material is probably enhanced by the use of a natural substance made of food-grade algae (FGA) and calcium alginate (CA), which has been cross-linked and loaded with ruthenium metal-organic frameworks (Ru-MOF). The Ru-MOF@FGA/CA beads were analyzed by XPS, PXRD, FT-IR, and SEM. The nitrogen adsorption-desorption isotherm analysis of the Ru-MOF@FGA/CA beads before and after the adsorption of RB revealed that had a surface area of 682 m2/g, a pore size of 2.92 nm, and a pore volume of 1.62 cc/g, that decreased after adsorption as the surface area reduced to 468.62 m2/g, while the pore volume reduced to 0.76 cc/g. indicating that the RB molecules occupied the available space within the pores of the material. The decrease in both surface area and pore volume specifies that the Ru-MOF@FGA/CA beads' pores were able to effectively adsorb the RB molecules. The adsorption of RB against the Ru-MOF@FGA/CA beads is affected by pH, adsorbent dose, starting RB concentration, and salinity. Controlling these factors can enhance the adsorption capability and effectiveness of the beads for RB removal. With an adsorption energy of 22.6 kJ/mol, the adsorption of RB onto the Ru-MOF@FGA/CA beads was determined to be a chemisorption process, demonstrating a strong bond among the adsorbent and the adsorbate. The pseudo-second-order kinetics and Langmuir isotherms were used to suit the adsorption process. Because the adsorption procedure was endothermic, it increased as the temperature increased. By using this information, the adsorption conditions may be improved, and the beads' ability to absorb RB can be increased. Up to six reuses of the Ru-MOF@FGA/CA beads are possible without affecting their chemical makeup and maintaining analogous PXRD and FT-IR data after each reuse. The adsorption process can be optimized through the application of the Box-Behnken design (BBD) approach and may entail H-bonding, electrostatic forces, n-π stacking, and pore filling. The exceptional stability of the beads makes them useful for creating long-lasting and efficient adsorbents that remove contaminants from water.

Lanthanum-based magnetic biopolymers for brilliant green removal from aqueous solutions

In this study, lanthanum (La)-based magnetic biopolymers were synthesized, and the first adsorption study was conducted on the removal of brilliant green dye from aqueous water with these biopolymers. For the adsorption study, adsorption parameters were investigated and the ideal adsorption conditions determined for the removal of brilliant green dye from aqueous solutions are pH 11, t 60 min, m 10 mg, C0 25 mg/L, T 298 K. It was determined that the adsorption process was compatible with the single-layer Langmuir isotherm, and maximum adsorption capacity obtained according to the Langmuir isotherm was calculated as 256.41 mg/g. The adsorption process was found to be in accordance with the pseudo-second-order, and the adsorption process was explained by intra-particle diffusion. According to studies of adsorption thermodynamics, it has been established that the nature of the adsorption reaction is spontaneous, and this process is endothermic and has increasing randomness. Moreover, the reusability of magnetic lanthanum/alginate (La/Alg) biopolymers was investigated, and it was determined that the biopolymers could be used successfully. In summary, brilliant green dye has been successfully removed with simple, low-cost, environmentally friendly, and easily obtained magnetic La/Alg biopolymers. It can be stated that even low amounts of these biopolymers can be effective in the treatment of highly concentrated dye wastewaters.

Enhancing brilliant green dye removal via bio composite chitosan and food-grade algae capsulated ruthenium metal-organic framework: Optimization of adsorption parameters by box-behnken design

A natural material made of chitosan (CS) and algae (food-grade algae, FGA) was cross-linked and loaded onto a ruthenium metal organic framework to create a bio-adsorbent (Ru-MOF@CS/FGA composite sponge) with the aim of adsorbing and eliminating Brilliant green (BG) from aqueous solutions. A range of methods were employed to analyze the Ru-MOF@CS/FGA composite sponge, such as X-ray photoelectron spectroscopy (XPS) for elemental analysis, Fourier transform infrared spectroscopy (FTIR) to ascertain the function groups, and scanning electron microscopy (SEM) to establish the surface morphology, and powder X-ray diffraction (PXRD) to study of single and multi-phase polycrystalline materials. Brunauer-Emmett-Teller surface area (BET) confirmed the adsorbent's high surface area and pore volume (826.85 m2/g and 1.28 cm3/g, respectively) and decreased to 475.62 m2/g and 0.74 cm3/g after adsorption. Determine the several factors that affect the adsorption process, such as pH, the adsorbent's dose, the initial BG concentration, and the effect of salinity. The adsorption process was fitted to pseudo-second-order kinetics and Langmuir isotherms. Dubinin-Radushkevich analysis revealed that the adsorption energy was 23.8 kJ/mol, indicating chemisorption as the mode of adsorption. It was discovered through examining the impact of temperature and computing positive-charged enthalpy and entropy that the adsorption process was endothermic, meaning that it increased in response to temperature. It is possible to reuse the Ru-MOF@CS/FGA composite sponge six times with acceptable efficiency, no change in its chemical composition, and comparable FT-IR, XPS, and XRD data before and after each reuse. Examine the mechanisms of adsorbent-adsorbate interaction, which may involve H-bonding, n-π stacking, electrostatic forces, and pore filling. The adsorption results were optimized with the Box Behnken-design (BBD).

Computational and experimental assessment of efficient dye adsorption method from aqueous effluents by halloysite and palygorskite clay minerals

The removal of dyes from effluents of textile industries represents a technological challenge, due to their significant environmental impact. The application of halloysite (Hal) and palygorskite (Pal) clay minerals as adsorbents for the removal of Congo red (CR) and methylene blue (MB) was evaluated in this work. The materials were applied both in natural and acid-treated forms, and characterized by XRD, XPS, SEM-EDS, FTIR, and N2 adsorption-desorption isotherm techniques to identify their properties and main active sites. The adsorbents showed potential to remove CR (> 98%) and MB (> 85%) within 180 min, using 0.3 g adsorbent and initial dye concentration of 250 mg L-1. Semi-empirical quantum mechanical calculations (SQM) confirmed the interaction mechanism between dyes and the adsorbents via chemisorption (- 69.0 kcal mol-1 < Eads <  - 28.8 kcal mol-1), which was further observed experimentally due to the high fit of adsorption data to pseudo-second order kinetic model (R2 > 0.99) and Langmuir isotherm (R2 > 0.98). The use of Pal and Hal to remove dyes was proven to be economically and environmentally viable for industrial application.

Fabrication of biogenic carbon-based materials from coconut husk for the eradication of dye

The highly biocompatible nature of carbon dots (CQDs) and potential usage in waste water treatment makes them as one of the effective alternative for treating water pollution. Herein, biogenic carbon dots (CQDs) with size range of 2 nm were prepared from waste coconut husk as a precursor source. The hydrophilic nature and higher surface area of as prepared CQDs has further supported the superior adsorption efficiency of more than 90% for Victoria blue B (VB) dye from waste water samples. Different dye adsorption parameters including adsorbate and adsorbent dosage, pH of reaction media and equilibrium time have been optimized and found that 8 mg of adsorbent was sufficient to remove 70 mg VB dye in 4 mL aqueous solution in 60 min at pH = 7. The adsorption kinetic (2nd order) and isotherms (Freundlich-type) were well followed on prepared CQDs. The reusability studies up to 5 times with minimal decrement of 4% confirm the constancy of CQDs for the adsorptive removal of VB. The methodology presents a greener way for overcoming ecological issues with sustainable materials in an economical manner.