Removal of anionic and cationic dyes from wastewater by adsorption using multiwall carbon nanotubes

Kinetics and process optimization studies for the effective removal of cresyl fast violet dye using reusable nanosized mullite

The swift rise of hazardous dye effluent from diverse sectors continues to be a severe public health problem and a top priority for environmental preservation, presenting a significant obstacle to the current conventional water treatment systems. This study aims to develop an efficient and reusable approach for removing cresyl fast violet dye using mullite nanoparticles. Some factors such as pH, nano-mullite dosage, agitation speed, time, and others that affect the removal process were studied. The mullite nanoparticles' shape, particle size, pore diameters, and crystal phase structure are characterized using many techniques such as Brunauer-Emmett-Teller (BET) surface area, X-ray diffraction (XRD), transmission electron microscopy (TEM), Contact angle, Zeta potential, scanning electron microscope (SEM) as well as energy dispersive X-ray analysis (EDX). The optimal conditions were pH 7 and 600 rpm for 30 min at room temperature. Using statistical programs such as ANOVA and Design Expert, the dye removal parameters were modeled and optimized, where the removal percentage was about 99%. In addition, the experimental elimination process exceeded 90% after just 10 min. Langmuir, Freundlich, Dubinin-Kaganer-Raduskevich (DKR), and Temkin isotherm equations were examined to find the adsorption isotherm. The experimental data fits the pseudo-second-order model and the Freundlich isotherm. Thermodynamic investigations confirmed that the adsorption process was endothermic and spontaneous. The nano-mullite was employed for the removal process, and its recycling ability supports its economic benefits. It was found that the high percentage of elimination remained consistent for more than 3 cycles.

Kinetics and adsorption isotherms studies for the effective removal of Evans blue dye from an aqueous solution utilizing forsterite nanoparticles

In the present day, water treatment has emerged as a significant global concern, particularly due to the proliferation of pollution sources. The utilization of dyes, such as Evans blue, in several industries is among the most significant contributors to these pollutants. Forsterite nanoparticles were synthesized by the sol-gel technique and calcined at different temperatures to determine the optimum temperature at which pure nanoforsterite was obtained. Then, it was analyzed using X-ray diffraction (XRD), atomic force microscope (AFM), transmission electron microscope (TEM), Brunauer-Emmett-Teller (BET) , contact angle, and zero-point charge. The adsorption capability of forsterite nanoparticles (Nps) was evaluated by a batch adsorption experimental method to remove Evans blue dye (EBD). Parameters such as agitation speed, dosage of forsterite Nps, pH, and contact time were considered at ambient temperature. At pH = 3, dose of Nps = 1 g/L, and 600 rpm within 10 min, the results indicated a removal rate of around 100%. Furthermore, it was shown that the material may be employed for 3 cycles with a removal rate of 90%. Multiple kinetic and isotherm models, including Langmuir, Temkin, and Freundlich models, were used to analyze the results and clarify the mechanism of the adsorption phenomena. The findings from the isotherm and kinetic studies indicated that the system conforms to Langmuir and pseudo-second-order, respectively.

Batch and column studies for the removal of basic red-46 dye and textile by using magnesium oxide (MgO), strontium titanium trioxide (SrTiO3), cobalt- and iron-doped lanthanum chromium trioxide (Co.Fe.LaCrO3), and cadmium sulfide (CdS)-doped graphene oxide nanocomposites

Despite efforts to reduce the risk of toxic chemicals, colors, and dyes being released into the environment from urban and industrial areas, there is still cause for concern. Colored water must be filtered and sterilized before it can be used for irrigation. The utilization of metal oxide and nanocomposite materials in wastewater treatment procedures appears to be a viable option for the future. Therefore, different compounds were doped with graphene oxide to identify the best material for dye removal by the adsorption process. According to recent studies, the ideal conditions for graphene oxide-doped magnesium oxide (GO/MgO) are as follows: pH 10 showed the highest adsorption capacity (qe) at 49.4 mg/g; an adsorbent dosage of 0.01 g/50 mL showed 48.3 mg/g qe; a shaking time of 30 min resulted in 44.2 mg/g qe; an initial dye concentration of 100 mg/L yielded 53.6 mg/g qe; and a temperature of 35 °C gave 49.5 mg/g qe. For graphene oxide-doped strontium titanate (GO/SrTiO3), the optimum conditions were as follows: pH 10 with 45.8 mg/g qe; an adsorbent dose of 0.01 g/50 mL with 40.5 mg/g qe; a shaking time of 30 min with 75 mg/g qe; and a temperature of 35 °C with 44.7 mg/g qe. Graphene oxide-doped cobalt and iron-doped lanthanum chromium titanate (GO/Co.Fe.LaCrO3) showed optimum conditions of pH 9 with 34.2 mg/g qe; an adsorbent dose of 0.01 g/50 mL with 27.5 mg/g qe; a shaking time of 45 min with 33.2 mg/g qe; an initial dye concentration of 100 mg/L with 37.6 mg/g qe; and a temperature of 35 °C with 42.5 mg/g qe. Graphene oxide-doped cadmium sulfide (GO/CdS) showed the following optimum conditions: pH 8 with 23.1 mg/g qe; an adsorbent dose of 0.01 g/50 mL with 25.5 mg/g qe; an initial dye concentration of 75 mg/L with 28.3 mg/g qe; and a temperature of 35 °C with 33.5 mg/g qe. The pseudo-first-order model was the best fit only for graphene oxide-doped magnesium oxide (GO/MgO) with an R2 value of 0.966, while the pseudo-second-order adsorption isotherm was the best fit for all four products, with R2 values ranging from 0.991 to 0.998. Additionally, the Langmuir adsorption isotherms provided good results for all four products, with R2 values ranging from 0.957 to 0.985. The Freundlich adsorption kinetics showed satisfactory fit only for graphene oxide-doped magnesium oxide (GO/MgO) and graphene oxide-doped cadmium sulfide (GO/CdS), with R2 values of 0.951 and 0.982, respectively. To examine the characteristics and practicality of the adsorption process, certain thermodynamic variables were calculated. The adsorption capability of the most efficient nanocomposites for the degradation of basic red-46 was significantly affected by various concentrations of heavy metal ions and electrolytes. In dye solutions containing surfactants/detergents, the adsorption efficiency of several effective photocatalysts for basic dyes was significantly reduced. A 0.5 M HCl solution was found to be the most effective for desorption. In column investigations, the optimal bed height, flow velocity, and dye intake levels were determined to be 3 cm, 1.8 mL/min, and 70 mg/L, respectively, for maximal adsorption of basic red-46. The adsorption investigation of genuine textile waste products has also been carried out to facilitate the practical deployment of this approach. The methods used in this study were cost-effective, easy to handle, and eco-friendly and involved no hazardous materials in the synthesis, making the resulting materials non-hazardous. All these methods were part of green chemistry.

Eco-friendly engineering of micro composite-based hydroxyapatite bio crystal and polyaniline for high removal of OG dye from wastewater: Adsorption mechanism and RSM@BBD optimization

The presence of harmful substances such as dyes in water systems poses a direct threat to the quality of people's lives and other organisms living in the ecosystem. Orange G (OG) is considered a hazardous dye. The existing paper attempts to evaluate a low-cost adsorbent for the effective removal of OG dye. The developed adsorbent Polyaniline@Hydroxyapatite extracted from Cilus Gilberti fish Scale (PANI@FHAP) was elaborated through the application of the in situ chemical polymerization method to incorporate PANI on the surface of naturally extracted hydroxyapatite FHAP. The good synthesis of PANI@FHAP was evaluated through multiple techniques including X-ray diffraction (XRD), Scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM/EDS), Fourier Transforms Infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) coupled with thermal differential analysis (DTA) analysis. The results reveal a highly ordered disposition of PANI chains on FHAP, resulting in a well-coated FHAP in the PANI matrix. Furthermore, the presence of functional groups on the surface of PANI such as amine (-NH2) and imine (=NH) groups would facilitate the removal of OG dye from contaminated water. The adsorption of OG onto PANI@FHAP was conducted in batch mode and optimized through response surface methodology coupled with box-Behnken design (RSM/BBD) to investigate the effect of time, adsorbent dose, and initial concentration. The outcomes proved that OG adsorption follows a quadratic model (R2 = 0.989). The kinetic study revealed that the adsorption of OG fits the pseudo-second-order model. On the other hand, the isotherm study declared that the Freundlich model is best suited to the description of OG adsorption. For thermodynamic study, the adsorption of OG is spontaneous in nature and exothermic. Furthermore, the regeneration-reusability study indicates that PANI@FHAP could be regenerated and reused up to five successive cycles. Based on the FTIR spectrum of PANI@FHAP after OG adsorption, the mechanism governing OG adsorption is predominantly driven by π-π interaction, electrostatic interaction, and hydrogen bonding interactions. The obtained results suppose that PANI@FHAP adsorbent can be a competitive material in large-scale applications.

Efficient extraction of textile dyes using reusable acrylic-based smart polymers

Water pollution from industrial or household waste, containing dyes from the textile industry, poses a significant environmental challenge requiring immediate attention. In this study, we have developed a crosslinked-smart-polymer film based on 2-(dimethylamino)ethyl methacrylate copolymerized with other hydrophilic and hydrophobic commercial monomers, and its efficacy in removing 21 different textile dyes was assessed. The smart polymer effectively interacts with and adsorbs dyes, inducing a noticeable colour change. UV-Vis spectroscopy analysis confirmed a removal efficiency exceeding 90 % for anionic dyes, with external diffusion identified as the primary influencing factor on process kinetics, consistent with both pseudo-first-order kinetics and the Crank-Dual model. Isothermal studies revealed distinct adsorption behaviors, with indigo carmine adhering to a Freundlich isotherm while others conformed to the Langmuir model. Permeation and fluorescence analyses corroborated isotherm observations, verifying surface adsorption. Significantly, our proof-of-concept demonstrated the resilience of the smart-film to common fabric softeners and detergents without compromising adsorption capacity. Additionally, the material exhibited reusability (for at least 5 cycles), durability, and good thermal and mechanical properties, with T5 and T10 values of 265 °C and 342 °C, respectively, a Tg of 168 °C, and a water swelling percentage of 54.3 %, thus confirming its stability and suitability for industrial application. ENVIRONMENTAL IMPLICATION: Dyes released during laundry processes should be classified as "hazardous materials" owing to their significant toxicity towards aquatic organisms, with the potential to disrupt ecosystems and harm aquatic biodiversity. This paper discusses the development of a novel acrylic material in film form, engineered to extract toxic anionic dyes. This study directly contributes to mitigating the environmental impact associated with the fashion industry and the domestic use of textiles. It can be implemented on both an industrial and personal scale, thereby encouraging more sustainable practices and promoting collaborative citizen science efforts towards.

Preparation and potential of chitosan-based/Al2O3 green hydrogel composites for the removal of methyl red dye from simulated solution

Different dyes are discharged into water streams, causing significant pollution to the entire ecosystem. The present work deals with the removal of acid red 2 dye (methyl red-as an anionic dye) by green sorbents based on chitosan derivatization. In this regard, two classes of chitosan derivatives-a total of six-were prepared by gamma irradiation at 30 kGy. The first group (group A) constitutes a crosslinked chitosan/polyacrylamide/aluminum oxide with different feed ratios, while the second group, identified as group B, is composed of crosslinked carboxymethyl chitosan/polyacrylamide/aluminum oxide with different ratios. Glycerol was added to soften the resultant hydrogels. The products were characterized by different tools, including FTIR for confirming the chemical modification, TGA for investigating their thermal properties, and XRD for verifying their crystalline structure. The morphology of the prepared derivatives was studied through SEM, while their topography before and after dye adsorption was monitored via the AFM. The removal efficiencies of the prepared sorbents were verified at different operation conditions, such as pH, temperature, adsorbent dose, initial concentration of dye solutions, and contact time. The data revealed that the optimum conditions for maximum dye uptake were as follows: pH 4, contact time 120 min, 0.1-g sorbent dose, and 50-ppm dye concentration. Additionally, the prepared sorbents demonstrated potent adsorption capacity and removal efficiency. It was found that the elements of the second group displayed higher performance than their counterparts. The data showed also that the adsorption process best fits with the Freundlich model and obeyed pseudo-first-order kinetic isotherm. In addition, the synthesized composites showed observable antibacterial potency toward E. coli as a Gram-negative bacterium and S. aureus as a Gram-positive bacterium.

Microorganism-mediated bioremediation of dyes from contaminated soil: Mechanisms, recent advances, and future perspectives

Many methods have been proposed for the remediation of dye-contaminated soils, a widespread form of environment pollution. Bioremediation, it is hoped, can combine ecological benefits with efficiency of dye decontamination. We review the types and sources of dye contaminants; their possible effects on plant, animal, and human health; and emerging strategies for microbial bioremediation. Challenges, limitations, recommendations for future research, and prospects for large-scale commercialization of microbial bioremediation are discussed.

Expermental investigation on adsorption of methylene blue dye from waste water using corncob cellulose-based hydrogel

Hydrogel from corncob cellulose was synthesized in this investigation. The synthesized Hydrogel was characterized by SEM, XRD, and FTIR instruments. As the results indicate the synthesized hydrogel has required and important features, these suggest the suitability of hydrogel for the adsorption of methylene blue dye (MBD). Three important process variables (dosage, contact time, and initial concentration) with three levels were studied during the adsorption process at 30 °C and neutral pH. The efficiency of hydrogel for adsorption of MBD was determined in each experiment. The experimental results were statistically analyzed and interpreted. The maximum removal efficiency was achieved at 2.22 g/L of dosage, 80.36 min of contact time, and 74.54 mg/L of initial concentration. At this condition, 98.25% of MBD was achieved through experimental tests. Kinetics, isotherm, and thermodynamics studies were performed. Langmuir isotherm is more suitable to describe the adsorption process and the Pseudo second-order kinetic model fits this process. From the thermodynamics studies, all negative values of change in Gibbs free energy (ΔG°), and positive value of change in enthalpy (ΔH°), and change in entropy (ΔS°) indicate that the carried out experimental process is a spontaneous and endothermic. Moreover, the regeneration experiment for adsorbent was performed. The treatment of real textile industry waste water was conducted and the removal efficiency of hydrogel was 64.76%. This removal percentage reduction from sythetic aqueous solution is due to involvement of other pollutants in the real waste water. The synthesized hydrogel adsorbent is suitable up to the third cycle without significant loss in removal efficiency.

Adsorption of contaminants by nanomaterials synthesized by green and conventional routes: a critical review

Nanomaterials, due to their large surface area and selectivity, have stood out as an alternative for the adsorption of contaminants from water and effluents. Synthesized from green or traditional protocols, the main advantages and disadvantages of green nanomaterials are the elimination of the use of toxic chemicals and difficulty of reproducing the preparation of nanomaterials, respectively, while traditional nanomaterials have the main advantage of being able to prepare nanomaterials with well-defined morphological properties and the disadvantage of using potentially toxic chemicals. Thus, based on the particularities of green and conventional nanomaterials, this review aims to fill a gap in the literature on the comparison of the synthesis, morphology, and application of these nanomaterials in the adsorption of contaminants in water. Focusing on the adsorption of heavy metals, pesticides, pharmaceuticals, dyes, polyaromatic hydrocarbons, and phenol derivatives in water, for the first time, a review article explored and compared how chemical and morphological changes in nanoadsorbents synthesized by green and conventional protocols affect performance in the adsorption of contaminants in water. Despite advances in the area, there is still a lack of review articles on the topic.

Annona glabra L. Seeds: An Agricultural Waste Biosorbent for the Eco-Friendly Removal of Methylene Blue

The seeds of Annona glabra L., an invasive plant in Vietnam, were first employed as a new biosorbent for the adsorption of methylene blue (MB) from aqueous media. The characterizations of the material using FT-IR, SEM, nitrogen adsorption-desorption analysis, and point of zero charge reveals that it possesses a rough and irregular surface, various polar functional groups, and pHpzc of 5.5. Certain adsorption conditions including adsorbent dose, solution pH, contact time, and initial concentration of MB were found to affect adsorption efficiency. The kinetic data are well fitted with pseudo-second-order model with the adsorption rate of 0.002 g mg-1 min-1 and initial rate of 4.46 mg g-1 min-1. For the adsorption isotherm, three nonlinear models were used to analyze the experiment data, including Langmuir, Freundlich, and Temkin. The results indicate that the Langmuir model best describes the adsorption of Annona glabra L. seeds powder (AGSP) with a maximum adsorption capacity of 98.0 mg g-1. The investigation underpins the adsorption mechanism, whereby the electrostatic attraction between positively charged MB and negatively charged surface of AGSP is expected to be the predominant mechanism, together with hydrogen bonding and pi-pi interaction. These results make AGSP an interesting biosorbent concerning its environmental friendliness, cost-effectiveness, and relatively high dye adsorption capacity.

Unveiling antibacterial and antioxidant activities of zinc phosphate-based nanosheets synthesized by Aspergillus fumigatus and its application in sustainable decolorization of textile wastewater

BACKGROUND

The development of an environment-friendly nanomaterial with promising antimicrobial and antioxidant properties is highly desirable. The decolorization potentiality of toxic dyes using nanoparticles is a progressively serious worldwide issue.

METHODS

The successful biosynthesis of zinc nanoparticles based on phosphates (ZnP-nps) was performed using the extracellular secretions of Aspergillus fumigatus. The antibacterial activity of the biosynthetic ZnP-nps was investigated against Gram-negative bacteria and Gram-positive bacteria using the agar diffusion assay method. The antioxidant property for the biosynthetic nanomaterial was evaluated by DPPH and H2O2 radical scavenging assay.

RESULTS

Remarkable antibacterial and antiradical scavenging activities of ZnP-nps were observed in a dose-dependent manner. The minimum inhibitory concentration (MIC) for Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli was 25 µg/ml, however, the MIC for Bacillus subtilis was 12.5 µg/ml. The maximum adsorptive performance of nanomaterial was respectively achieved at initial dye concentration of 200 mg/L and 150 mg/L using methylene blue (MB) and methyl orange (MO), where sorbent dosages were 0.5 g for MB and 0.75 g for MB; pH was 8.0 for MB and 4.0 for MO; temperature was 30 °C; contact time was 120 min. The experimental data was better obeyed with Langmuir's isotherm and pseudo-second-order kinetic model (R2 > 0.999). The maximum adsorption capacity (qmax) of MB and MO dyes on nanomaterial were 178.25 mg/g and 50.10 mg/g, respectively. The regenerated nanomaterial, respectively, persist > 90% and 60% for MB and MO after 6 successive cycles. The adsorption capacity of the prepared zinc phosphate nanosheets crystal toward MB and MO, in the present study, was comparable/superior with other previously engineered adsorbents.

CONCLUSIONS

Based on the above results, the biosynthesized ZnP-nanosheets are promising nanomaterial for their application in sustainable dye decolorization processes and they can be employed in controlling different pathogenic bacteria with a potential application as antiradical scavenging agent. Up to our knowledge, this is probably the first study conducted on the green synthesis of ZnP-nanosheets by filamentous fungus and its significant in sustainable dye decolorization.

Sol-Gel Functionalized Polyurethane Foam-Packed Mini-Column as an Efficient Solid Extractor for the Rapid and Ultra-Trace Detection of Textile Dyes in Water

Textile dyes widely used in industrial products are known as a major threat to human health and water ecological security. On the other hand, sol gel represents a principal driver of the adoption of dispersive solid-phase microextractors (d-µ SPME) for pollutants residues in water. Thus, the current study reports a new and highly rapid and highly efficient hybrid sol-gel-based sponge polyurethane foam as a dispersive solid-phase microextractor (d-µ-SPME) platform packed mini-column for complete preconcentration and subsequent spectrophotometric detection of eosin Y textile dye in wastewater. The unique porous structure of the prepared sol-gel immobilized polyurethane foams (sol-gel/PUF) has suggested its use for the complete removal of eosin Y dye (EY) from water. In the mini-column, the number (N) of plates, the height equivalent to the theoretical plates (HETP), the critical capacity (CC), and the breakthrough capacities (BC) of the hybrid sol-gel-treated polyurethane foams towards EY dye were determined via the breakthrough capacity curve at various flow rates. Under the optimum condition using the matrix match strategy, the linear range of 0.01-5 µg L-1, LODs and LOQs in the range of 0.006 µg L-1, and 0.01 µg L-1 for wastewater were achieved. The intra-day and inter-day precisions were evaluated at two different concentration levels (0.05 and 5 μg L-1 of dye) on the same day and five distinct days, respectively. The analytical utility of the absorbents packed in pulses and mini-columns to extract and recover EY dye was attained by 98.94%. The column could efficiently remove different dyes from real industrial effluents, and hence the sol-gel/PUF is a good competitor for commercial applications. The findings of this research work have strong potential in the future to be used in selecting the most suitable lightweight growing medium for a green roof based on stakeholder requirements. Therefore, this study has provided a convenient pathway for the preparation of compressible and reusable sponge materials from renewable biomass for efficient removal of EY from the water environment.

Adsorption of direct blue 106 dye using zinc oxide nanoparticles prepared via green synthesis technique

Zinc oxide nanoparticles (ZnO-NPs) have in recent times shown effective adsorption capability for the confiscation of colour contaminants from aqueous environments (aquatic ecosystems or water bodies) due to the fact that ZnO contains more functional groups. Direct blue 106 (DB106) dye was selected for this present study as a model composite due to its wide range of uses in textiles (cotton and wools), woods, and paper industries, as well as their therapeutic applications, along with its potential for impairments. This study therefore focuses on the use of DB106 dye as a model composite due to its wide range of uses in textiles (cotton and wools), woods, and paper industries, as well as their therapeutic applications and their potential for impairments. Furthermore, the surface functionalization, shape, and composite pore size were revealed by TEM, FTIR, UV, and BET techniques. The current study uses green synthesis method to prepare ZnO-NPs as an adsorbent for the DB106 dye molecules adsorption under various conditions using the batch adsorption process. The adsorption of DB106 dye to the ZnO-NPs biosorbent was detected to be pH-dependent, with optimal adsorption of DB106 (anionic) dye particles observed at pH 7. DB106 dye adsorption to the synthesized ZnO-NPs adsorbent was distinct by means of the linearized Langmuir (LNR) and pseudo-second-order (SO) models, with an estimated maximum adsorption capacity (Q_m) of 370.37 mg/g.

Utilization of metal industry solid waste as an adsorbent for adsorption of anionic and cationic dyes from aqueous solution through the batch and continuous study

Industrial waste, for instance, textile effluents when released into the ecological system without first being treated or with inappropriate levels of treatment, can lead to serious issues deteriorating the environment and human health. Moreover, solid waste from various industries has also become a major issue due to massive urbanization. For instance, the waste from the metal industry has been rapidly increasing such as Jarosite which has various metals, metal oxides, and silica in its composition. Therefore, Jarosite was utilized as an adsorbent for the adsorption of anionic Congo red (CR) and cationic Methylene blue (MB) dyes from aqueous solutions. The processed adsorbent sample was characterized by BET, XRD, SEM, EDS, FTIR, and XPS techniques. The effects of initial dye concentration, pH, adsorbent dose, temperature, and contact time were examined. The metal industry waste is used as a low-cost abundant adsorbent with great potential for adsorption ability to remove the CR (97.5%) and MB (68.5%) at pH 7, contact time 90 min, adsorbent dose 0.1 g, and initial dye concentration 50 mg/L. The adsorption data followed the adsorption isotherm and Kinetics for both dyes. The removal of both dyes was a physical adsorption process, endothermic and spontaneous reaction. Column adsorption investigation was described by AB (Adams-Bohart) and YN (Yoon-Nelson) models. According to the economic view, the utilization of jarosite for dye removal is a cost-effective approach, because it is collected free of cost from industries. Henceforth, for the first time, toxic metal industry waste was successfully utilized as an adsorbent for wastewater treatment.

Study on the Adsorption Properties of Oxalic Acid-Modified Cordierite Honeycomb Ceramics for Neutral Red Dyes

Removal of organic dyes from water by monolithic adsorbents is considered as an efficient and no-secondary pollution method. Herein, for the first time cordierite honeycomb ceramics (COR) treated with oxalic acid (CORA) were synthesized. This CORA exhibits outstanding removal efficiency toward the azo neutral red dyes (NR) from water. After optimizing the reaction conditions, the highest adsorption capacity of 7.35 mg·g^-1 and a removal rate of 98.89% could be achieved within 300 min. Furthermore, investigation of the adsorption kinetics indicated this adsorption process could be described as a pseudo-second-order kinetic model with k ₂ and q _e of 0.0114 g·mg^-1·min^-1 and 6.94 mg·g^-1, respectively. According to the fitting calculation, the adsorption isotherm could also be described as the Freundlich isotherm model. The removal efficiency could be maintained above 50% after 4 cycles, negating the need for toxic organic solvent extraction, offering a method for bringing the technology one step closer to industrial application and giving CORA promising potential in practical water treatment.

Preparation and Characterization of a Renewable Starch-g-(MA-DETA) Copolymer and Its Adjustment for Dye Removal Applications

Maleic anhydride-diethylenetriamine grafted on starch (st-g-(MA-DETA)) was synthesized through graft copolymerization, and the different parameters (copolymerization temperature, reaction time, concentration of initiator and monomer concentration) affecting starch graft percentage were studied to achieve the maximum grafting percentage. The maximum grafting percentage was found to be 29.17%. The starch and grafted starch copolymer were characterized using XRD, FTIR, SEM, EDS, NMR, and TGA analytical techniques to describe copolymerization. The crystallinity of starch and grafted starch was studied by XRD, confirming that grafted starch has a semicrystalline nature and indicating that the grafting reaction took place typically in the amorphous region of starch. NMR and IR spectroscopic techniques confirmed the successful synthesis of the st-g-(MA-DETA) copolymer. A TGA study revealed that grafting affects the thermal stability of starch. An SEM analysis showed the microparticles are distributed unevenly. Modified starch with the highest grafting ratio was then applied to celestine dye removal from water using different parameters. The experimental results indicated that St-g-(MA-DETA) has excellent dye removal properties in comparison to native starch.

Nanomaterials photocatalytic activities for waste water treatment: a review

Water is necessary for the survival of life on Earth. A wide range of pollutants has contaminated water resources in the last few decades. The presence of contaminants incredibly different dyes in waste, potable, and surface water is hazardous to environmental and human health. Different types of dyes are the principal contaminants in water that need sudden attention because of their widespread domestic and industrial use. The toxic effects of these dyes and their ability to resist traditional water treatment procedures have inspired the researcher to develop an eco-friendly method that could effectively and efficiently degrade these toxic contaminants. Here, in this review, we explored the effective and economical methods of metal-based nanomaterials photocatalytic degradation for successfully removing dyes from wastewater. This study provides a tool for protecting the environment and human health. In addition, the insights into the transformation of solar energy for photocatalytic reduction of toxic metal ions and photocatalytic degradation of dyes contaminated wastewater will open a gate for water treatment research. The mechanism of photocatalytic degradation and the parameters that affect the photocatalytic activities of various photocatalysts have also been reported.

Spherical mesoporous silica designed for the removal of methylene blue from water under strong acidic conditions

This work proposes a novel technology for environmental remediation based on mesoporous silica spheres, which were successfully synthesized by the solvothermal method using the cetyltrimethylammonium bromide as a structuring agent. The adsorbent was designed to remove cationic dyes at strong acidic conditions. The surface was modified by a careful thermal treatment aiming at the condensation of silanol to siloxane groups. The adsorbent was characterized by XRD, SEM, FTIR, N₂ adsorption/desorption and the equilibrium technique to determine the pH_pzc. The kinetic of the adsorption followed a pseudo-second-order model and the process was ruled by physical forces. The isotherms were fitted to Freundlich and Temkin models, indicating that the physisorption occurred with multilayer formation, with the interaction adsorbate-adsorbate being relevant to the whole process. The adsorption capacity was approximately 60 mg g^-1 and the adsorbents performance in the fast-contact system showed removal of 65%wt. of a 93 mg L^-1 methylene blue (MB) solution in a single application.

Biodegradable cellulose nanocrystals hydrogels for removal of acid red 8 dye from aqueous solutions

Biodegradable cellulose nanocrystals hydrogels (CNCsH) were synthesized from cellulose nanocrystals (CNCs) which were prepared from office wastepaper (OWP) by a chemical crosslinking method using epicholorohydrin (ECH) as a cross-linker. CNCsH were tested for their swelling behavior and biodegradability and the point of zero charge had been determined. The ability of CNCsH for removing the Acid Red 8 (AR8) anionic dye from its aqueous solution was evaluated. The different parameters affecting removal of the dye, such as pH, initial concentration of dye, content of CNCs, temperature and adsorbent dosage were investigated. The optimum conditions for 68% removal efficiency were pH = 1, initial concentration of dye = 10 ppm, contact time = 105 min, CNCs content = 5% and CNCsH dosage = 0.5 g at 30 °C. The adsorption isotherms, kinetics, and thermodynamic parameters have been studied. The results showed an appropriate fit for Langmuir adsorption isotherm and pseudo-second order kinetics model with an adsorption capacity of 17.12 mg/g. According to the obtained values of thermodynamic parameters, the removal of Acid red 8 by CNCs hydrogels was exothermic spontaneous process.

Taguchi L25 (54) Approach for Methylene Blue Removal by Polyethylene Terephthalate Nanofiber-Multi-Walled Carbon Nanotube Composite

A membrane composed of polyethylene terephthalate nanofiber and multi-walled carbon nanotubes (PET NF-MWCNTs) composite is used to adsorb methylene blue (MB) dye from an aqueous solution. Scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction techniques are employed to study the surface properties of the adsorbent. Several parameters affecting dye adsorption (pH, MB dye initial concentration, PET NF-MWCNTs dose, and contact time) are optimized for optimal removal efficiency (R, %) by using the Taguchi L25 (54) Orthogonal Array approach. According to the ANOVA results, pH has the highest contributing percentage at 71.01%, suggesting it has the most significant impact on removal efficiency. The adsorbent dose is the second most affected (12.08%), followed by the MB dye initial concentration of 5.91%, and the least affected is the contact time (1.81%). In addition, experimental findings confirm that the Langmuir isotherm is well-fitted, suggesting a monolayer capping of MB dye on the PET-NF-MWCNT surface with a maximum adsorption capacity of 7.047 mg g−1. Also, the kinetic results are well-suited to the pseudo-second-order model. There is a good agreement between the calculated (qe) and experimental values for the pseudo-second-order kinetic model.

Super-Adsorptive Biodegradable Hydrogel from Simply Treated Sugarcane Bagasse

There is a great demand for biodegradable hydrogel, and cellulose enriched wastes materials are widely used to serve this purpose for various advance applications (e.g., biomedical and environmental). Sugarcane bagasse is cellulose-enriched agro-waste, abundantly grown in Bangladesh. This study aimed to treat sugarcane bagasse-based agro-waste using a sustainable and ecofriendly approach to produce hydrogel with super-swelling capacity for adsorption of copper, chromium, iron ions, methylene blue and drimaren red dyes. To increase the swelling property of hydrogels, copolymerization of hydrophilic monomers is an effective technique. Therefore, this study aimed to prepare hydrogel via free radical graft-copolymerization reaction among acrylamide, methyl methacrylate and treated bagasse in the presence of N,N-methylene-bis-acrylamide as a crosslinker and potassium persulphate as an initiator. To obtain maximum yield, reaction conditions were optimized. It was found that hydrogel obtained from chemically treated sugarcane bagasse showed maximum water absorption capacity of 228.0 g/g, whereas untreated bagassebased hydrogel could absorb ~50 g/g of water. Maximum adsorption capacity of 247.0 mg/g was found for copper ion. In addition, organic pollutant removal from industrial effluent also showed good performance, removing >90% of methylene blue and 62% of drimaren red dye, with shorter kinetics. The biodegradability study showed that after 90 days of exposure, the hydrogels degraded to about 43% of their own mass. Therefore, the produced hydrogel could be an alternative adsorbent to remove pollutants and also for other potential applications.

Optimization of Decoloration Conditions of Methylene Blue Wastewater by Penicillium P1

The objective of this work was to optimize the decolorization of methylene blue dye wastewater by Penicillium P1. The influencing factors included initial methylene blue concentration, initial pH value, salinity and inoculation percentage of penicillium spores. The decolorization rate was optimized by response surface center composite design methods. The optimal optimization condition was methylene blue concentration 50 mg/L, pH value 3.61, salinity 3.7%, and inoculation percentage 3.21% (When the MSM was 100 ml), the predicted decolorization rate of methylene blue 85%. The UV and the FTIR spectrum analysis showed that the structure of methylene blue changed during the process of decolorization of methylene blue by Penicillium P1.

Label free detection of auramine O by G-quadruplex-based fluorescent turn-on strategy

Auramine o (AO) is a synthetic dye used in paper and textile industries. Although it has been an unauthorized food additive in many countries due to its toxic and carcinogenic possibility, its illegal uses have been detected in certain food products such as pasta, semolina and spices and also in pharmaceuticals. The presence of AO in food products should be monitored, therefore, to minimize the negative health effects on consumers. In this study, a simple, highly sensitive and selective label free detection method was investigated for AO by G-quadruplex-based fluorescent turn-on strategy. The optimum fluorescent detection assay was achieved with a specific G-quadruplex DNA sequence, c-myc, at 400 nM in Tris-HCl buffer at pH 7.4. The linearity of fluorescence intensity depending on AO concentration ranged from 0 to 0.07 µM and LOD and LOQ were 3 nM and 10 nM, respectively. The G-quadruplex-based detection assay was highly specific for AO as compared to other two synthetic food colorings and successfully applied to determine AO in pasta, bulgur and curry powder with recoveries in the range from 70.33% to 106.49%. This G-quadruplex-based label free detection assay has a significant potential to be used in the detection of AO in food products.

Graphene oxide loaded fibrous matrixes of polyether block amide (PEBA) elastomer as an adsorbent for removal of cationic dye from wastewater

Novel highly porous nanoparticle materials are increasingly being applied in adsorption processes, but they need to be supported by robust matrixes to maintain their functionality. We present a study of hosting graphene oxide (GO) particles on polyether block amide (PEBA) melt electrospun fibers and applying such composite matrix to the adsorption of the cationic dye (crystal violet) from water. Various amounts of GO (from 0.5 to 2.0%) were mixed into pure PEBA and electrospun by melt electrospinning obtaining micro fibrous matrixes. These were characterized for morphology (SEM), chemical composition (FTIR), crystallinity (XRD), and wetting behavior (WCA). The increasing amount of GO adversely affected fiber diameter (reduced from 13.18 to 4.38 μm), while the hydrophilic properties (Water contact angle decrease from 109 to 76°) and overall dye adsorption was increased. Efficient adsorption has been demonstrated, reaching approximately 100 % removal efficiency using a 2% GO composite matrix at a dose of 40 mg/l and pH of 10. Further increase of GO concentration in polymer is not feasible due to instability in the electrospinning process.

Modern Carbon-Based Materials for Adsorptive Removal of Organic and Inorganic Pollutants from Water and Wastewater

Currently, a serious threat for living organisms and human life in particular, is water contamination with persistent organic and inorganic pollutants. To date, several techniques have been adopted to remove/treat organics and toxic contaminants. Adsorption is one of the most effective and economical methods for this purpose. Generally, porous materials are considered as appropriate adsorbents for water purification. Conventional adsorbents such as activated carbons have a limited possibility of surface modification (texture and functionality), and their adsorption capacity is difficult to control. Therefore, despite the significant progress achieved in the development of the systems for water remediation, there is still a need for novel adsorptive materials with tunable functional characteristics. This review addresses the new trends in the development of new adsorbent materials. Herein, modern carbon-based materials, such as graphene, oxidized carbon, carbon nanotubes, biomass-derived carbonaceous matrices-biochars as well as their composites with metal-organic frameworks (MOFs) and MOF-derived highly-ordered carbons are considered as advanced adsorbents for removal of hazardous organics from drinking water, process water, and leachate. The review is focused on the preparation and modification of these next-generation carbon-based adsorbents and analysis of their adsorption performance including possible adsorption mechanisms. Simultaneously, some weak points of modern carbon-based adsorbents are analyzed as well as the routes to conquer them. For instance, for removal of large quantities of pollutants, the combination of adsorption and other methods, like sedimentation may be recommended. A number of efficient strategies for further enhancing the adsorption performance of the carbon-based adsorbents, in particular, integrating approaches and further rational functionalization, including composing these adsorbents (of two or even three types) can be recommended. The cost reduction and efficient regeneration must also be in the focus of future research endeavors. The targeted optimization of the discussed carbon-based adsorbents associated with detailed studies of the adsorption process, especially, for multicomponent adsorbate solution, will pave a bright avenue for efficient water remediation.

A systematic literature review on the current detection tools for authentication analysis of cosmetic ingredients

BACKGROUND

The use of cosmetic products is considered a necessity for beautification in our daily lives. Cosmetic products composed of natural oils or fats as a main ingredient for various beneficial properties. Fats and oils are composed of various type of fatty acids with different compositions. Hence, fatty acids profile can be an effective chemical fingerprint for authentication analysis of cosmetic products.

OBJECTIVE

This systematic review aims to enlighten the current detection tools developing for fatty acids profile authentication analyses of cosmetic ingredients based on the effectiveness, halal status, safety, advantages and disadvantages of the methods.

METHODOLOGY

The data were extracted from the scientific literatures published between October 2015 and 2020 in the Web of Science, Scopus and Google Scholar databases, and analyzed with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

FINDINGS

Based on the systemic literature reviews, essential oil, argan oil, mineral oil, vegetable oil, and jojoba oil were among the mostly studied ingredients in cosmetics. Furthermore, a combination of more than one analytical instrument was utilized to profile fatty acids while the determination of the origin of the fatty acids is under scrutiny. The portable mass spectrometer combined with a direct inlet membrane (DIM) probe seems to be the best tool in terms of time consumption, cost, requires no sample preparation with high efficiency. The current review showed that the best cosmetic base is when the oil is composed of high concentration of fatty acids such as linoleic, oleic, stearic acid, and palmitic acids with concentration range from 19.7 - 46.30%, which offers various beneficial properties to cosmetic products.

Emerging novel polymeric adsorbents for removing dyes from wastewater: A comprehensive review and comparison with other adsorbents

Dye molecules are one of the most hazardous compounds for human and animal health and the excess intake of these materials can create toxic impacts. Several studies show the practicality of the adsorption process for dye uptake from wastewaters. In recent years, various adsorbents were used to be efficient in this process. Among all, polymeric adsorbents demonstrate great applicability in different environmental conditions and attract many researchers to work on them, although there is not enough reliable and precise information regarding these adsorbents. This study aims to investigate some influential parameters such as their type, physical properties, experimental conditions, their capacity, and further modeling along with a comparison with non-polymeric adsorbents. The influence of the main factors of adsorption capacity was studied and the dominant mechanism is explained extensively.

Application of Taguchi method and response surface methodology into the removal of malachite green and auramine-O by NaX nanozeolites

In the present study, the simultaneous removal of malachite green (MG) and auramine-O (AO) dyes from the aqueous solution by NaX nanozeolites in a batch system is investigated. Taguchi method and response surface methodology (RSM) were used to optimize and model dye removal conditions. In order to do so, the effect of various factors (dyes concentration, sonication time, ionic strength, adsorbent dosage, temperature, and pH of the solution) on the amount of dye removal was evaluated by the Taguchi method. Then, the most important factors were chosen and modeled by the RSM method so as to reach the highest percentage of dye removal. The proposed quadratic models to remove both dyes were in good accordance with the actual experimental data. The maximum removal efficiencies of MG and AO dyes in optimal operating conditions were 99.07% and 99.61%, respectively. Also, the coefficients of determination (R2) for test data were 0.9983 and 0.9988 for MG and AO dyes, respectively. The reusability of NaX nanozeolites was evaluated during the adsorption process of MG and AO. The results showed that the adsorption efficiency decreases very little up to five cycles. Moreover, NaX nanozeolites were also applied as adsorbents to remove MG and AO from environmental water samples, and more than 98.1% of both dyes were removed from the solution in optimal conditions.

Crystal violet dye sorption over acrylamide/graphene oxide bonded sodium alginate nanocomposite hydrogel

The synthesis of acrylamide bonded sodium alginate (AM-SA) hydrogel and acrylamide/graphene oxide bonded sodium alginate (AM-GO-SA) nanocomposite hydrogel was successfully performed using the free radical method. The AM-SA and AM-GO-SA hydrogels were applied as composited adsorbents in crystal violet (CV) dye removal. The adsorption process experiments were performed discontinuously and the acquired data showed that the efficiency is more dependent on pH than other factors. The C-O, CO, and CC groups were detected in the produced hydrogels. The amount of surface area was computed to be 44.689 m²/g, 0.0392 m²/g, and 6.983 m²/g for GO, AM-SA, and AM-GO-SA nanocomposite hydrogel, respectively. The results showed that the experimental data follow the Redlich-Peterson isotherm model. Also, the maximum adsorption capacity of monolayer for CV dye adsorption was determined using AM-SA hydrogel and AM-GO-SA nanocomposite hydrogel 62.07 mg/g and 100.30 mg/g, respectively. In addition, the parameters R_L, n, and E showed that the processes of adsorption of CV dye using both types of adsorbents are physical and desirable. Thermodynamically, the CV elimination was exothermic and spontaneous. Besides, thermodynamic results showed that the adsorption process is better proceeding at low temperatures. The experimental data followed a pseudo- second- order (PSO) kinetic model. Also, the Elovich model showed that AM-GO-SA nanocomposite hydrogel has more ability to absorb CV dye. Therefore, according to the obtained results, it can be stated that the produced hydrogels are efficient and viable composited adsorbent in removing CV dye from aqueous solution.

Haematological, biochemical, enzymological and histological responses of Labeo rohita exposed to methyl orange dye solution treated with Oedogonium subplagiostomum AP1

The present investigation is an attempt to assess the impact of untreated methyl orange and Oedogonium subplagiostomum AP1 treated methyl orange dye solutions on Labeo rohita. The behavioural response, mortality, haematological (red blood corpuscles (RBC), packed cell volume (PCV), haemoglobin (Hb), white blood corpuscles (WBC), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC)), biochemical (plasma glucose and protein), enzymological (aspartate amino transaminases (AST) and alanine amino transaminases (ALT)) and histological examination (gills, liver and kidney) of Labeo rohita are exposed to untreated and treated methyl orange dye solutions were assessed on 7th day. The fish exposed to tap water and treated dye solution showed normal behavioural response whereas abnormal behaviour was noted in fish exposed to untreated dye solution. Similar trend was recorded in the mortality rate of the fishes. Fish exposed to untreated dye solution showed reduction in RBC, PCV, Hb, MCHC, plasma glucose and plasma protein, increased level of WBC, MCV and MCH and also alteration in AST and ALT thereby indicating the toxicity of the dye. No such reduction and alteration were observed in haematological, biochemical and enzymological levels of fishes exposed to tap water and treated dye solution indicating the non-toxic nature of the degraded metabolites of dye. Histological examination of fishes exposed to methyl orange dye revealed necrosis and haemorrhage in the gills and hepatocytes, congested and shrunken glomeruli in kidney thereby indicating the toxicity of the dye. The histoarchitecture of control and algae-treated fishes showed no structural changes indicating the non-toxic nature of the degraded metabolites of the dye. The results concluded that methyl orange dye solution treated with O. subplagiostomum AP1 can be explored for aquacultural purposes owing to its non-toxic nature.

Extremely efficient and rapidly adsorb methylene blue using porous adsorbent prepared from waste paper: Kinetics and equilibrium studies

For the first time, zinc chloride activation method was used to prepare waste paper-based activated carbon in this study. The structure, morphology, surface functional groups and particle size distribution of the activated carbon was study using automatic specific surface area analyzer, FTIR, Boehm titration, X-ray diffraction, SEM and EDS. The specific surface area of the activated carbon is up to 1987 m²/g. Cumulative pore volume is up to 2.586 cm³/g, with micropore volume accounting for 92 %. Methylene blue adsorption performance results shown that the adsorbent has achieved high removal efficiency (99.65 % in 10 min, uptake = 996.5 mg/g), its maximum adsorption capacity has reached 1657 mg/g. The pH_pzc of the adsorbent was determined to explore the adsorption mechanism, its results shown that electrostatic adsorption occurs between adsorbents and adsorbents at pH higher than pH_pzc (pH_pzc = 3.2). Moreover, adsorption mechanism was studied by various isothermal models, thermodynamic models, kinetic models. Redlich-Peterson isotherm model best describes the adsorption experiment, which indicated that the adsorption follows a non-ideal and mixed adsorption mechanism. Methylene blue molecules gone into micropore was the adsorption rate-limiting step, and MB adsorption by the waste paper-based adsorbent was a spontaneous, endothermic and randomly increasing adsorption. Simulated wastewater and regeneration experiments were also used to evaluate the adsorbent's treatment capacity and economic efficiency, and these results indicated that the adsorbent has good decolorization and regeneration ability.

Dye removal from water and wastewater by nanosized metal oxides - modified activated carbon: a review on recent researches

The conventional water and wastewater treatment methods are unable to provide up-to-data organized standards for drinking water and discharging effluents into natural ecosystems. Therefore, developing advanced and cost-effective methods to achieve published standards for water and wastewater and population needs are nowadays necessity. The important parts of this article are providing literature information about dyes and their effects on the environment and human health, adsorption properties and mechanism, adsorbent characteristics, and recent information on various aspects of modified activated carbons with nanosized metal oxides (AC- NMOs) in the removal of dyes. This review also summarized the effect of main environmental and operational parameters such as adsorbent dosage, pH, initial dye concentration, contact time, and temperature on the dye adsorption using AC-NMOs. Furthermore, the applied isotherm and kinetic models have been discussed.

Biogenic and chemically synthesized Solanum tuberosum peel-silver nanoparticle hybrid for the ultrasonic aided adsorption of bromophenol blue dye

This work was aimed at the synthesis of a hybrid (STpe-AgNP), obtained by impregnation of silver nanoparticles (AgNP) onto Solanum tuberosum peel (STpe), for the ultrasonic assisted adsorption of bromophenol blue (BB) dye. SEM, FTIR, XRD, EDX, TGA and BET techniques were used to characterize the adsorbents. The XRD, SEM and EDX confirmed successful impregnation of AgNPs onto STpe to form the hybrid. The AgNPs impregnated onto the hybrid were found to be water stable at various pH values of 2.0-9.0. Chi-square (χ2 < 0.024) and linear regression (R2 > 0.996) showed that the Freundlich model was best fitted among the isotherm models, corroborated by the oriented site model. Kinetic analysis conformed to the intraparticle diffusion and pseudo-first-order rate equations, while thermodynamics displayed a physical, spontaneous and endothermic adsorption process. The presence of competing Pb(II), Ni(II), Cd(II) and Zn(II) metal ions in solution interfered with the adsorption of BB onto the biosorbents. In terms of reusability, STpe and STpe-AgNP showed BB desorption of 91.3% and 88.5% respectively, using NaOH as eluent. Ultra-sonication significantly enhanced the adsorption of BB by both adsorbents, but the impregnation of AgNPs only slightly improved adsorption of the dye from the simulated wastewater. This study also illustrated that pristine STpe biomass waste is a cheap viable option for the decontamination of BB from water.

Biosorption and regeneration potentials of magnetite nanoparticle loaded Solanum tuberosum peel for celestine blue dye

This research evaluated the adsorption of celestine blue (CB) onto a novel Solanum tuberosum waste-magnetite nanocomposite (Mt@STB), prepared by an ecofriendly impregnation of magnetite (Mt) nanoparticles onto Solanum tuberosum waste (STB). The adsorbents characterization revealed that Mt@STB had a surface area (18.92 m²/g), pHpzc (7.55), porous morphology as well as suitable functional groups for efficient sequestration of CB onto the composite. The SEM, XRD, and EDX showed successful incorporation of 31.21 nm average size Mt nanoparticles on Mt@STB. Faster kinetics of CB sequestration from the wastewater was obtained for Mt@STB (100 min) compared to STB (140 min). Among four isotherm models, the Langmuir exhibited the best fit with R² > 0.9971 and sum square errors (SSE) < 0.0151. The pristine STB and Mt@STB composite showed maximum monolayer CEB uptake of 7.61 and 9.02 mg/g, as well as optimum removal of 73.8 and 84.7%, respectively. The pseudo-second-order model was more suitable in the kinetic description, while thermodynamics revealed a physical, spontaneous, and endothermic CB uptake. Besides, the efficacy of the composite for CB was confirmed from efficient regeneration over three adsorption/desorption cycles, which specified the viability of Mt@STB as a sustainable material for the decontamination of CB polluted water. NOVELTY STATEMENT The adsorption of dyes from wastewaters has been widely studied due to the harmful effects on the ecosystem. However, research on the removal of celestine blue (CB) dye is rare despite its wide use in the nuclear and textile industries. Until date, there is no report on the adsorption of CB on biomaterial via biosorption. Therefore, the biosorption behavior of CB is presently unknown. Hence, this study reports the biosorption of CB onto a biosorbent (Solanum tuberosum peel [STB]) in an attempt to understand its biosorption behavior. Besides, the impregnation of magnetite (Mt) nanoparticles has been reported to enhance the uptake of most adsorbents for dye. To the best of our knowledge, such magnetic nanoparticle impregnation of STB has not been reported. We, therefore, synthesized a novel biowaste-magnetite composite (Mt@STB) and evaluated its potentials for the uptake as well as its reuse for CB biosorption.

Synthesis, characterization, and regeneration of an inorganic-organic nanocomposite (ZnO@biomass) and its application in the capture of cationic dye

Despite the efficiency of ZnO nanoparticle (NPs) composite adsorbents in the adsorption of various pollutants, there is presently no report on the combo of ZnONPs with biomass for adsorption. Besides, there is a dearth of information on the biosorption of celestine blue (CEB), a dye used in the nuclear and textile industry. In this study, biogenic-chemically mediated synthesis of a composite (ZnO@ACP) was prepared by the impregnation of ZnONPs onto Ananas comosus waste (ACP) for the adsorption of CEB. The SEM, EDX, FTIR, XRD, BET, and TGA characterizations showed the successful presence of ZnONPs on the biomass to form a nanocomposite. The uptake of CEB was enhanced by the incorporation of ZnONPs on ACP. A faster CEB adsorption onto ZnO@ACP (120 min) compared to ACP (160 min) was observed. The Langmuir (R² > 0.9898) and pseudo-second-order (R² > 0.9518) models were most appropriate in the description of the adsorption process. The impregnation of ZnONPs onto the biomass enhanced the spontaneity of the process and displayed endothermic characteristics. High CEB desorption of 81.3% from the dye loaded ZnO@ACP as well as efficient reusability showed the efficacy of the prepared nanocomposite for CEB adsorption.