Efficient Adsorption Of Methylene Blue Research Articles

Producing Efficient Adsorbents from Kraft Lignin for the Removal of Contaminants from Water—A Full Factorial Design

This work aimed at optimizing the preparation of activated carbon (AC) from Kraft lignin for the adsorption of methylene blue (MB) and amoxicillin (AMX) from water. A full factorial design of three factors (precursor:activating agent (H3PO4) ratio, pyrolysis temperature, and residence time) at two levels was used to optimize the AC production. Eight AC products were obtained and evaluated considering the following responses: product yield, specific surface area (SBET), energy consumption, and adsorptive removal of the contaminants under study. The produced AC presented satisfactory SBET, ranging between 750 and 1335 m2 g−1, and efficient adsorption of MB and AMX from water, achieving up to 99% removal under the studied experimental conditions (100 mg L−1 of MB and AMX solution and material dose of 1 g L−1). Statistical analysis showed that product yield and energy consumption for AC production were influenced by temperature and residence time. The determination of a desirability function indicated a precursor/H3PO4 ratio of 1:2, pyrolysis at 700 °C, and residence time of 60 min as the optimal production conditions. The optimized AC presented SBET 1335 m2 g−1 and maximum adsorption capacity of 210 and 280 mg g−1 for MB and AMX, respectively.

In situ growth of HKUST-1 on electrospun polyacrylonitrile nanofibers/regenerated cellulose aerogel for efficient methylene blue adsorption

Dyes, as organic pollutants, are causing increasingly severe environmental problems. Metal-organic frameworks (MOFs) are considered promising dye adsorbents; however, their application is limited due to their powder or solid particle forms and limited reusability. Therefore, this study proposes an innovative approach to develop a novel MOF-based composite aerogel, specifically a HKUST-1/polyacrylonitrile nanofibers/regenerated cellulose (HKUST-1/PANNs/RC) composite aerogel adsorbent, for the adsorption of pollutants in water. This adsorbent was successfully prepared using a simple method combining covalent crosslinking, quick freezing, freeze-drying, in-situ growth synthesis, and solvothermal techniques. The HKUST-1/PANNs/RC composite aerogel exhibits a significantly large specific surface area, which is approximately 64 times greater than that of PANNs/RC (10.45 m2·g−1), with a specific surface area of 669.9 m2·g−1. The PANNs serve as a support framework, imparting excellent mechanical properties to the composite aerogel, enhancing its overall stability and recoverability. Additionally, the composite aerogel contains numerous -COOH and -OH groups on its surface, providing strong acid resistance and facilitating interactions with pollutant molecules through electrostatic interactions, π-π conjugation, n-π* interactions, and hydrogen bonding, thereby promoting the adsorption process. Using methylene blue (MB) as a probe molecule, the study results demonstrate that the HKUST-1/PANNs/RC composite aerogel has an adsorption capacity of 522.01 mg·g−1 for MB (25 h), exhibiting excellent adsorption performance. This composite aerogel shows great potential for application in water pollution control.

Preparation of carboxymethyl cellulose/graphene oxide/ZIF-8 aerogels for efficient methylene blue adsorption

Despite the promising potential of zeolitic imidazole framework-8 (ZIF-8) for dye adsorption, addressing challenges such as aggregation and recycling difficulties remains essential. Herein，a novel three dimensional (3D) carboxymethyl cellulose (CMC), graphene oxide (GO) and ZIF-8 hybrid aerogel (CGZ-3) was prepared via blending ZIF-8 into the CMC-GO matrix. The structure and composition of CGZ-3 were characterized by SEM, FT-IR, TG and XPS. Adsorption experiments were conducted to optimize various parameters affecting the behavior of methylene blue (MB) adsorption. The composite aerogel exhibited an obvious lamellar network structure, with a surface rich in oxygen-containing functional groups such as -OH and -COOH. CGZ-3 demonstrated a rapid adsorption rate for MB, achieving a removal efficiency of 96% within 15 minutes. The entire adsorption process was spontaneous and endothermic, consistent with the pseudo-first-order kinetic model and Langmuir adsorption isotherm model. The maximum theoretical adsorption capacity was 427.35 mg/g at 298 K. Selective adsorptions tests demonstrated high selectivity of the composite aerogel for MB, and dynamic adsorption further confirmed the exceptional adsorption capacity of CGZ-3. After five cycles of adsorption-desorption, the MB removal rate remained above 95%, with an adsorption capacity exceeding 240 mg/g, highlighting the stability and reusability of CGZ-3. Collectively, the CGZ-3 would be a potential material for the adsorptive removal of MB in practical water treatment.

Advancements in water purification: green synthesis of pineapple peel-derived iron manganese binary oxide magnetic nanocomposites for efficient methylene blue adsorption

Advancements in water purification: green synthesis of pineapple peel-derived iron manganese binary oxide magnetic nanocomposites for efficient methylene blue adsorption

Ultrasonic-assisted in situ synthesis of MOF-199 on the surface of carboxylated cellulose fibers for efficient adsorption of methylene blue.

A high-efficiency porous adsorbent, MOF-199/carboxylated cellulose fibers (MOF-199/CCF), was synthesized in situ at room temperature through carboxylation modification, simple sonication, and vacuum drying. The sonication method produced small MOF-199 particles (tens of nanometers), which allowed for uniform distribution of MOF-199 on CCF and improved its efficiency. The presence of CCF carriers reduces the agglomeration of MOF-199 and enhances its performance. The BET-specific surface area of MOF-199/CCF is 264.83 m2 g-1, which is much larger than that of CCF (2.31 m2 g-1), proving the successful modification of CCF by MOF-199. MOF-199/CCF exhibits better adsorption capacity than CCF, with an adsorption capacity of 659.6 mg g-1 of methylene blue within 30 minutes, and good recycling performance. This work presents a straightforward method for preparing efficient cellulose-based adsorbent materials and offers a novel approach for synthesizing MOF composites.

Preparation of porous silica materials using a eucalyptus template method and its efficient adsorption of methylene blue

Methylene blue (MB) is a prevalent pollutant in organic wastewater. For this research, eucalyptus wood was used as a template, into which quartz powder dissolved in NaOH was grown, resulting in a low-cost and efficient porous silica adsorbent material (PSAM). This PSAM successfully replaces expensive materials for MB removal from water. Through the application of Scanning Electron Microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis, it became evident that PSAM displays a porous slit pore structure characterized by numerous active sites, leading to an impressive maximum specific surface area of 88.05 m²/g. The central objective of this research was to investigate the impact of experimental temperature, initial dye concentration, and pH on the adsorption process. The adsorption kinetics were analyzed using the pseudo-first-order and pseudo-second-order models, as well as the Langmuir model. Remarkably, PSAM exhibited a substantial maximum adsorption capacity of 90.01 mg/g at 293 K, achieving an adsorption rate of over 85% within a mere 10-minute timeframe. The thermodynamic analysis revealed that the adsorption of MB onto PSAM was characterized by spontaneity and accompanied by heat absorption. Fourier Transform Infrared (FTIR) and SEM comparisons of PSAM before and after adsorption indicated that MB adsorption primarily occurred through electrostatic gravitational binding. In comparison to other adsorbents, PSAM exhibited exceptional efficacy in removing MB from water.

Porous BCNO fibers for efficient methylene blue adsorption from aqueous solution

With the development of dye production and the printing/dyeing industry, the discharge of dyestuff wastewater has sharply increased, posing a threat to the health of organisms. Therefore, it is necessary to develop efficient adsorbent materials to remove dyes. Porous BCNO (pBCNO) was prepared via pyrolysis of melamine borate modified by hydroxyethyl cellulose (HEC). Compared to traditionally pyrolytic melamine borate, the incorporation of HEC can not only alter the product's microstructure, but also significantly adjust its bonding and chemical composition. Specifically, the specific surface area and total pore volume of pBCNO are as high as 1102.4 m2/g and 0.55 cm3/g, respectively. The generation of B–N, C–B, C–O, N–C and B–O bonds enriches the bonding and chemical activity of pBCNO. Encouraged by these unique microstructures and chemical compositions, pBCNO exhibits excellent methylene blue (MB) adsorption and recycling capabilities, showing a maximum adsorption capacity and removal efficiency of 709.5 mg/g and 99.9 %, respectively. The adsorption behavior is dominated by chemical adsorption, following Langmuir adsorption theory and pseudo-second-order model. This study not only provides a new synthesis route to pBCNO, but also establishes an experimental and theoretical foundation for the practical adsorption of pBCNO toward organic pollutants in industrial effluent.

Alginate–based aerogel fibers with a sheath–core structure for highly efficient methylene blue adsorption via directed freezing wet–spinning

Developing adsorbent materials based on biomass that can be easily recycled and reused to remove water pollutants has received widespread attention. A novel method for the preparation of calcium alginate/poly (vinyl alcohol)/boric acid (as–synthesized Ca-APB) aerogel fibers for highly efficient adsorption of methylene blue by directed freezing wet–spinning was presented in this paper. The Ca-APB-0.5 aerogel fibers exhibited a hierarchical structure consisting of a honeycomb micron pore structure with mesopores walls, with a maximum adsorption capacity of 508.99 mg/g in 5 h at 293 K. Meanwhile, the experimental data for Ca-APB-0.5 aerogel fibers showed the best fit to the Freundlich model and pseudo–second–order model. Moreover, the adsorption capacity was investigated for three consecutive cycles, with 469.37, 457.19, and 439.77 mg/g in the first, second, and third cycles, respectively. This paper proves that the hierarchical structure of alginate-based aerogel fiber is an effective dye adsorption material with high efficiency, reusability, and eco-friendliness.

Simple Alkali-Modified Persimmon Peel–Montmorillonite Composite Hydrochar for Rapid and Efficient Removal of Methylene Blue

Modified persimmon peel–montmorillonite composites (PMHC-KOH/NaHCO3) for efficient and rapid removal of methylene blue (MB) were synthesized using hydrothermal carbonization and simple alkali impregnation. The surface properties and material compositions of the hydrochars were determined with SEM, zeta potential, and XRD, and the adsorption mechanism of MB on two modified hydrochars was analyzed with FTIR, XPS, and DFT calculation. The results showed that modified hydrochars with a rough surface structure and rich oxygen-containing groups exhibited a strong affinity for MB, and the adsorption capacity of PMHC-NaHCO3 and PMHC-KOH for MB reached 121.28 mg/g and 278.41 mg/g, respectively, with PMHC-KOH achieving more rapid adsorption of MB, at a rate of 0.043 g/mg/min. After five adsorption/desorption cycles, the two modified hydrochars still maintained a high adsorption rate of MB (92.32%/98.43%). The excellent adsorption performance of the modified hydrochars was attributed to hydrogen bonding, π-π interaction, electrostatic attraction, and ion exchange. DFT calculations revealed that oxygen-containing groups of the modified hydrochars played an important role in the adsorption of MB and confirmed that electrostatic attraction, hydrogen bonding, and π-π interactions were the key forces for rapid and efficient adsorption of MB. The prepared adsorbents gave full play to the regenerative applicability of agricultural waste, the simple alkali impregnation method eliminated the need for the additional cost of pyrolysis and activation, and their application in MB adsorption realized the treatment of waste with waste.

Synthesis of hierarchical porous carbon sphere via crosslinking of tannic acid with Zn2+ for efficient adsorption of methylene blue

Hierarchical porous carbon spheres (HPCS) were synthetized utilizing tannic acid as biomass source and Zn2+ as cross-linking agent. Metal Zn2+ prove to be pivotal in the preparation of materials, which can promote the formation of spherical structure and make materials have both micropores and mesopores. The adsorbent has regular spherical shape, specific surface areas of>1000 m2/g, the maximum adsorption capacity (qmax) of methylene blue is 697 mg/g. It has stable adsorption performance in a broad pH environment (3–11), and the methylene blue removal remains at 91.9% after five cycles. The hierarchical porous structure is beneficial to the immobilization process of methylene blue, and hydrogen bonding, π-π interaction and electrostatic attraction are the main forces for the immobilization of methylene blue. This research offers a promising way for the exploration of biomass-based materials for efficacious dye removal.

Performance of TiO2/Ag/CA for efficient adsorption of methylene blue

The incorporation of additives and inclusion of metal dopants on titanium dioxide (TiO2) could improve its inherent limitations and result in enhanced photocatalytic efficiency. In this work, the performance of TiO2/Ag with the use of cellulose acetate (CA) was investigated for the degradation of a model dye pollutant under different operational settings. The surface morphology, elemental composition, crystallinity, and band gap of TiO2/Ag/CA composite were verified by scanning electron microscopy, energy-dispersive X-ray, X-ray diffraction, and UV–Vis diffuse reflectance spectroscopy, respectively. An increase in CA concentration from 1 to 2 wt% led to the high removal of methylene blue (MB). The highest removal of MB (90.90%) was obtained by TiO2/Ag/CA under the conditions of 4 g/L catalyst loading, 5 ppm MB concentration, and at unadjusted pH (7.8). The recyclability study showed that the removal efficiency of the retrieved photocatalyst remains as much as ~ 78% after 3 cycles, demonstrating its sustainability in water treatment. The remarkable adsorption effect shown by CA as an additive greatly enhanced the removal of MB by the TiO2/Ag photocatalyst under UV irradiation and dark condition. The TiO2/Ag/CA composite, which has dual roles in adsorption and photocatalysis, could be employed as a pollution removal agent in water.

Integration of Phosphotungstic Acid into Zeolitic Imidazole Framework-67 for Efficient Methylene Blue Adsorption.

To enhance the dye adsorption capacity of zeolitic imidazolate framework-67 (ZIF-67), phosphotungstic acid (HPW) was integrated into ZIF-67 to prepare composite adsorbents. Characterization results demonstrated that the electronegative HPW was uniformly and tightly deposited on the electropositive ZIF-67. Methylene blue (MB) was selected as a model contaminant to evaluate the adsorption performance of hybrid adsorbents. Results showed that HPW@ZIF-67 had excellent adsorption capacity toward cationic MB. The optimal ZIF-67-0.2 HPW sample with a HPW dosage of 9.9 wt % presented an adsorption capacity of 446.4 mg g–1. ZIF-67-0.2 HPW displayed good reusability, and the adsorption data can be well described by pseudo-second order and Langmuir isotherm models. The adsorption mechanism was ascribed to the preferred electrostatic attraction and π–π stacking between MB and composite adsorbents. This work provides a route to enhance organic dye removal efficiency of ZIF materials through regulation of surface charge property and sheds light on the development of ZIF-based adsorbents.

Structure engineering of Fe-based MOF aerogel by Halloysite Nanotubes for efficient methylene blue adsorption

Structure engineering of Fe-based MOF aerogel by Halloysite Nanotubes for efficient methylene blue adsorption

Facile synthesis of mesoporous silica derived from iron ore tailings for efficient adsorption of methylene blue

The recycle of iron ore tailings is of great significance for environmental protection and sustainable development. In this paper, a facile approach to synthesize mesoporous silica derived from iron ore tailings is reported. The influence of alkali fusion and acid leaching treatment on microstructures and physicochemical properties of iron ore tailings is investigated in detail. The alkali fusion treatment destructed the network structure, converting the iron ore tailings to highly reactive state. The following acid leaching treatment selectively dissolved the metal ions to form abundant porous structures, and generated silica nanoparticles with inter-particle mesopores. The as-obtained mesoporous silica showed a specific surface area of 544.68 m2 g−1 with well-developed porosity. As an adsorbent, the prepared mesoporous silica material showed good monolayer adsorption with adsorption capacity of 192 mg g−1 for methylene blue dye in aqueous solution. This study provides a new way to convert iron ore tailings into high-value-added mesoporous materials, which has the potential application in environment protection.

Modification of graphene aerogel with titania nanotubes for efficient methylene blue adsorption kinetics

Titania nanotubes (TNTs) with high length–diameter ratio are incorporated into reduced graphene oxide (rGO) aerogel to modify the porous structure of the obtained rGO/TNTs aerogel for efficient methylene blue (MB) adsorption. A hydrothermal method along with freeze drying is applied for the preparation of the rGO/TNTs composite aerogel. The uniformly dispersed TNTs in rGO matrix can effectively support the network structure and hinder the π–π bonding interaction between graphene sheets, thus resulting in a three-dimensional mesoporous network with high specific surface area. The rGO/TNTs aerogel shows favorable adsorption property toward MB and the maximum adsorption capacity can be 380.7 mg g−1 with the adsorption efficiency of 92.2%. Besides, the adsorption kinetic analysis reveals that a dispersion process is found to be the rate-limiting step when the adsorbent dosage is low. With the increase of adsorbent content, chemical sorption such as the π–π interaction or the reaction of the polar functional groups between MB and rGO–TNTs-C aerogel becomes the rate-limiting step.

A Double cross-linked strategy to construct graphene aerogels with highly efficient methylene blue adsorption performance

A novel lysine and EDA double cross-linked graphene aerogel (LEGA) was constructed. The prepared LEGA was utilized as a methylene blue (MB) adsorbent in the wastewater treatment. It exhibits a three-dimensional interconnected porous structure benefiting dye adsorption. Its compression property is highly enhanced with the addition of lysine. Adsorption isotherm and kinetics of MB onto LEGA were discussed. Their results show that MB adsorption onto LEGA was fitted to follow Langmuir adsorption isotherm model and the pseudo-second-order kinetic model. LEGA has an excellent adsorption capacity towards MB as high as 332.23 mg/g and its MB adsorption process is proved to be an exothermic process. The mechanism for MB adsorption onto LEGA was proposed as the ion exchange, electrostatic interaction, π-π stacking interaction and hydrogen bonding. Thus, LEGA is confirmed to be a sustainable and green MB adsorbent with highly removal efficiency in the treatment of wastewater.

Mussel-inspired polydopamine functionalized recyclable coconut shell derived carbon nanocomposites for efficient adsorption of methylene blue

Relatively cheap or at no cost, easily available, renewable agricultural waste has been given a new purpose. Using coconut shells as the raw material, and being obtained from agricultural, industry by-products, or even waste materials were used as carbon resource. Acid etching coconut shells carbon (AC) rendered micro/nanoscale hierarchical structures and made the surface available for further modification. Then, the surface of acidified coconut shell carbon was engineered via mussel inspired chemistry. The polydopamine functionalized AC composites (AC-PDA) were applied for efficient removal of methylene blue (MB) dye. Further, the surface morphology, and chemical structure were evaluated by means of scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR). Through the combination of acid etching and mussel inspired chemistry, organic functional groups can be successfully introduced onto the surface of the coconut shells carbon. The improvement of adsorption capacity of AC-PDA compared with AC is probably due to the increased number of active binding sites resulting from surface modification and formation of new functional groups.

Reusable, few-layered-MoS2 nanosheets/graphene hybrid on cellulose paper for superior adsorption of methylene blue dye

High efficient methylene blue adsorption by MoS2 micro-flowers on graphene-cellulose paper.

Ionic polyacrylamide hydrogel improved by graphene oxide for efficient adsorption of methylene blue

The ionic polyacrylamide/graphene oxide (PAM/GO) hydrogel as an excellent methylene blue (MB) adsorbent was prepared by an improved one-step radical polymerization method using graphene oxide, acrylamide, and polar second monomers. The hydrogel was characterized by Fourier transform infrared spectroscopy, Raman spectra, X-ray diffraction, scanning electron microscopy, and 13C nuclear magnetic resonance spectrum. The effects of pH, contact time, initial concentration of MB, and temperature on the adsorption capacity for MB of the prepared hydrogel were investigated. The Langmuir isotherm was a suitable model for describing the adsorption process. The adsorption system fitted with the pseudo-second-order kinetic model in the adsorption process. Compared with the ionic PAM/GO, the anionic PAM/GO significantly improved the adsorption capacity for MB with an increase from 128.23 to 255.48 mg g−1 at 20 °C.

Extremely fast and efficient methylene blue adsorption using eco-friendly cork and paper waste-based activated carbon adsorbents

Abstract For the first time the feasibility of using an alkaline wastewater coming from the pulp and paper industry as an activator, partially (50 vol%) replacing commercial sodium hydroxide, in the production of cork-based activated carbons was evaluated. The activated carbons showed the highest value of specific surface area ever reported for cork-based activated carbons (1670 m2/g), surpassing several other commercial and waste-based ones. These eco-friendly cork and paper waste-based activated carbons were then evaluated as methylene blue adsorbent materials. The influence of contact time, methylene blue initial concentration and adsorbent amount on the methylene blue removal efficiency by the activated carbons was studied. Extremely fast (>99.9% removal in 5 min) and efficient methylene blue adsorption (uptake of 350 mg/g) by the cork and paper waste-based adsorbents was achieved, which demonstrates the huge potential of these innovative adsorbents. These activated carbons were produced using two unexplored industrial by-products (alkaline wastewater and cork) and, therefore, may be an inexpensive source of activated carbons, which can be used for the effective removal of dyes from wastewaters. Furthermore, despite the very large surface area and high removal efficiency this is not a nano material (being around 30–50 μm in size), its capabilities being due to its unique cork-derived microstructure, and hence it can be handled and removed/filtered much more easily than nanocarbons, and without any associated health or environmental risks.