High-capacity adsorption of aniline using surface modification of lignocellulose-biomass jute fibers

Usage of magnetic activated carbon as a potential adsorbent for aniline adsorption from wastewater

Aniline, a hazardous aromatic compound, is a notable contaminant in various industrial wastewater. As a simple and convenient process, adsorption could facilitate aniline adsorption from sewage. Magnetic activated carbon adsorbent (MAC) was produced using the co-precipitation method and applied to the adsorption of aniline from water. The characterization of this adsorbent was surveyed using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), and Vibrating-Sample Magnetometer (VSM). Key operational parameters, including adsorbent dosage, initial aniline concentration, and initial pH, have been systematically investigated using the Central Composite Design (CCD) approach in the Response Surface Method (RSM). According to the results, the optimal adsorption percentage was achieved with a 2.9 g/L dosage, pH 7.4, 52.7 mg/L initial concentration, and 300 min of contact time. A study on Langmuir, Freundlich, and Sips isotherms was conducted, alongside evaluating pseudo-first-order and pseudo-second-order kinetics. The Sips isotherm and pseudo-second-order models showed the best fit, with R2 values > 0.98 and 0.99, respectively. The thermodynamic study indicated a negative ΔG, confirming that aniline adsorption is spontaneous on both commercial and magnetic activated carbon.

Physicochemical, structural, and adsorption characteristics of DMSPS-co-DVB nanopolymers

The aim of this work is the synthesis and characterization of the series of S,S'-thiodi-4,1-phenylene bis(thio-methacrylate)-co-divinylbenzene (DMSPS-co-DVB) nanomaterials. The series of new nanopolymers including three mixed systems with different ratios of DMSPS and DVB components, DMSPS-co-DVB = 1:1, DMSPS-co-DVB = 1:2, and DMSPS-co-DVB = 1:3, was synthesized in the polymerization reaction. The research task is to investigate the influence of the reaction mixture composition on morphological, textural, and structural properties of final nanosystems including size, shape, and agglomeration effect. The advanced biphasic nanomaterials enriched with thiol groups were successfully synthesized as potential sorbents for binding organic substances, heavy metals, or biomolecules. To determine the impact of the DMSPS monomer on the final properties of DMSPS-co-DVB nanocomposites, several techniques were applied to reveal the nano-dimensional structure (SAXS), texture (low-temperature nitrogen sorption), general morphology (SEM), acid-base properties (potentiometric titration), and surface chemistry and phase bonding effectiveness (FTIR/ATR spectroscopy). Finally, kinetic studies of aniline sorption on polymeric materials were performed.

A Sandwich Structure of Fulvic Acid and PMIDA-Modified LDHs for the Simultaneous Removal of Cu2+ and Aniline in Multicomponent Solutions

The coexistence of organic and inorganic pollutants in industrial wastewater has emerged as a concerning environmental issue worldwide due to the critical levels of biological toxicity of these pollutants. In this context, the present study proposes a sandwich structure of fulvic acid and PMIDA-modified LDHs (FA/PMIDA-LDHs) for the simultaneous removal of Cu²⁺ and aniline from wastewater. The specific structure was synthesized using a combination of coprecipitation and impregnation methods. Abundant benzene rings and oxygen-containing functional groups greatly increased the number of sites for the adsorption of both Cu²⁺ and aniline. The maximum adsorption capacity of Cu²⁺ and aniline in solution with initial pH 5.0 at 25 °C could reach 221.24 and 132.28 mg/g, respectively. Cu²⁺ could be chelated by the functional groups in the FA/PMIDA-LDHs structure, and a coupled reduction-complexation mechanism was proposed for this process. The uptake of aniline on FA/PMIDA-LDHs was demonstrated to be a result of the combination of coordination forces, hydrophobic effects, π-π interactions, and hydrogen bonds. In a multicomponent solution, FA/PMIDA-LDHs exhibited excellent salt tolerance of up to 1000 mg/L of Na⁺ or Ca²⁺. The effects of Fe³⁺, Ni²⁺, Cl^-, Cr₂O₇^2-, SO₄^2-, and H₂PO₄^- on the uptakes of Cu²⁺ and aniline were also investigated.

Highly efficient preferential adsorption of Pb(II) and Cd(II) from aqueous solution using sodium lignosulfonate modified illite

In this study, sodium lignosulfonate modified illite (LS-ILT), an environmentally friendly adsorbent, was prepared by hydrothermal modification. An extensive study of Pb(II) and Cd(II) adsorption behavior and the mechanisms were conducted by evaluating the effects of initial pH value, sorbents dosage, and initial concentration of Pb(II) and Cd(II). Results showed that the adsorption characteristics of Pb(II) and Cd(II) by LS-ILT were well described by quasi-second-order kinetics and the Freundlich model, and the maximum adsorption capacity of Pb(II) and Cd(II) was 42.3 mg/g and 17.0 mg/g, respectively. The optimal application conditions for adsorption equilibrium were the dosage of 4 g/L and reaction pH = 5.5-5.8. The adsorption stability of Pb(II) by LS-ILT was better than that of Cd(II), and most of the existence of coexisting cations had no obvious inhibitory effect on the removal of Pb(II) and Cd(II). Furthermore, the dynamic adsorption results showed that LS-ILT can meet the ultra-low emission standard, and the adsorption capacity could maintain over 50% after four cycles, further providing certain guiding significance for the treatment of wastewater with ultra-low concentrations of heavy metals Pb(II) and Cd(II).

A censorious review on the role of natural lignocellulosic fiber waste as a low-cost adsorbent for removal of diverse textile industrial pollutants

BACKGROUND

Textile industries produce fabricated colored products using toxic dyes and other harsh chemicals. It is the responsibility of the textile industries to treat and eliminate these hazardous pollutants. However, due to the growing population demand, the treatment of these hazardous effluents is ineffective and imposes the treatment cost over the end users. The release of partially treated effluents in the environment may cause a severe threat to the ecology and its biota. The critical objective is to treat textile effluents efficiently using agricultural natural fiber waste. Generation of agricultural lignocellulosic fibrous waste increases every year due to growing population demand. Its use in the modern world is limited due to synthetic products. An alternative has enumerated to avoid wastage of fibrous resources and its clean disposal.

OBJECTIVE

The main objective of this review paper discussed the feasibility of lignocellulosic fibers and other lignocellulosic materials as natural low-cost adsorbent.

METHODS

The literature study was performed using Web of Science and Scopus indexed journals. The main factors considered to increase the adsorption ability, including the types of lignocellulosic surface modification techniques were searched with utmost importance for quality results. Intending to summarize the literature survey and provide persuasive content, systematic review process was considered for this novel article.

RESULTS

Out of 230 valuable publications, 159 published articles were considered for the present study until March 2022. The articles surplus with factors affecting adsorption (pH, adsorption dosage, surface area, temperature, initial concentration, contact time, physical and chemical properties of pollutants) and surface modification techniques (physical, chemical, and biological) were considered for this manuscript.

CONCLUSION

Overall, the physical and chemical modification methods are widely used instead of biological methods due to various factors as discussed briefly. Furthermore, the finding of this article supports the fact that the fibrous by-product resources are wasted in various occasions due to the modern lifestyle. Even though there is evidential possibility to implement the low-cost adsorbents, the industries limit their application prospects due to existing technology and financial compromises.

Synthesis of polystyrene-based hyper-cross-linked polymers for Cd(II) ions removal from aqueous solutions: Experimental and RSM modeling

The hyper-cross-linked polymers (HCPs) based on the polystyrene was synthesized during the Friedel-Craft reaction in various situations. The HCPs synthesis were carried out in various operating conditions including reaction time in the range of 3-23 h, the ratio of cross-linker to monomer in range of 1-5 at temperature of 80 ℃. In addition, the cadmium adsorption process was carried out at a temperature in the range of 25-85 ℃ and initial cadmium concentration in the range of 10-100 mg/L. The response surface methodology (RSM) has been applied for optimizing the process using synthesis and adsorption parameters. The optimized synthesis conditions were obtained 3.32, 11.26 h, 80 ℃, in ratio, synthesis time, and temperature, respectively. Also, the optimized adsorption conditions were obtained 80 mg/L and 35 ℃, initial cadmium ion concentration, and temperature, respectively. The surface area and thermal stability were obtained at 853.89 m²/g and 450 ℃, respectively. The maximum adsorption capacity and removal efficiency had been obtained 950 mg/g and 92% at a temperature of 20 ℃, after 80 min, respectively. The maximum adsorption capacity and removal efficiency were observed in the initial concentration of 120 mg/L and 10 mg/L, respectively. The adsorption process behavior was surveyed using isotherm, kinetic and thermodynamic models. The isotherm results showed that the adsorption of cadmium by HCPs is multi-layer and heterogeneous. The thermodynamic parameters showed that the process is exothermic and spontaneous. Finally, the kinetic results showed that the process occurred physically and slowly as the temperature raised.

Hydroxyl modified hypercrosslinked polymers: targeting high efficient adsorption separation towards aniline

The removal of aniline from aqueous solution has a major environmental impact and attracted increasing attention in last few years.

Preparation of PP-g-(AA-MAH) Fibers Using Suspension Grafting and Melt-Blown Spinning and its Adsorption for Aniline

This paper uses polypropylene (PP) as the matrix and acrylic acid (AA) and maleic anhydride (MAH) as functional monomers to prepare PP-g-(AA-MAH) fibers by suspension grafting and melt-blown spinning technology that are easy to industrially scale-up. The fibers can be used to adsorb aniline. Results showed that the grafting ratio reached the maximum of 12.47%. The corresponding optimal conditions were grafting time of 3 h, AA: MAH = 0.75, total monomer content of 55%, benzoyl peroxide 1.4%, xylene concentration of 6 mL/g PP, and deionized water content of 8 mL/g PP. Owing to its good fluidity and thermal stability, the product of suspension grafting can be used for melt-blown spinning. Infrared spectroscopic and nuclear magnetic resonance spectroscopic analyses indicated that AA and MAH were successfully grafted onto PP fibers. After grafting, the hydrophilicity of PP-g-(AA-MAH) fiber increased. Therefore, it had higher absorptivity for aniline and the adsorption capacity could reach 42.2 mg/g at 45 min and pH = 7. Moreover, the PP-g-(AA-MAH) fibers showed good regeneration performance.

Green Carbon Material for Organic Contaminants Adsorption

Eco-friendly and economical adsorbents are desirable for removing organic pollutants from the environment. Herein, a kind of green carbon material, electrolytic carbon (EC) prepared by the electrochemical conversion of greenhouse gas (CO₂) in molten carbonate, is verified as an effective adsorbent for aniline and other small aromatic organic molecules. The EC consists of nanoparticles and nanoflakes, featuring the specific surface area of ∼641 m²/g with an enriched micropore structure. It exhibits a large adsorption capacity (Q_max > 114.1 mg/g) for aniline, especially in water with a lower contamination level. The adsorption conforms to the pseudo-second-order equation kinetically and the Freundlich model thermodynamically in the temperature range of 303-323 K. Moreover, it is found that the adsorption performance of the material can be further improved through reducing surface oxygen functional groups by a simple thermotreatment. Its adsorption capacity for aniline is enhanced by 1.7 times, demonstrating that the π-π dispersive interaction plays a primary role for the efficient adsorption. This adsorption mechanism is further confirmed by the excellent adsorption performance of the carbon materials for other analogue aromatic compounds (phenol, nitrobenzene). The super performance of the CO₂-derived carbon adsorbents will be helpful for capturing CO₂ as well as for removing organic pollutants.

High-efficiency adsorption and regeneration of methylene blue and aniline onto activated carbon from waste edible fungus residue and its possible mechanism

Edible fungus residue as an efficient and low-cost precursor was used to produce Edible Fungus residue Activated Carbon (EFAC) using the zinc chloride activation method at a 1 : 2 impregnation ratio and 600 °C activation for 3 hours. The activation process does not need gases like nitrogen and is suitable for mass production. Fungal biodegradation facilitates efficient chemical activation, which might have generated abundant pores on the activated carbon sample. Using BET, X-ray diffraction (XRD), scanning electron microscopy (SEM), and FTIR characterization, reveals that EFAC exhibits a large specific surface area (1070 m² g⁻¹), and large pore volume (0.68 cm³ g⁻¹), with its surface displaying a honeycomb-like structure. The EFAC adsorbs methylene blue (MB) and aniline in water, with maximum adsorptions of 662.25 and 27.10 mg g⁻¹, respectively. Various adsorption conditions, such as the EFAC dosage, pH, contact time and initial concentration were investigated. The adsorption is characterized by the pseudo-second-order kinetic and Langmuir isotherm models, with thermodynamics studies indicating that the adsorption is endothermic and spontaneous. Furthermore, the EFAC exhibited good regeneration performance by a 90% ethanol solution. The EFAC is a low-cost and environmentally friendly adsorbent for removing organic contaminants in wastewater.

Edible fungus residue as an efficient and low-cost precursor was used to produce Edible Fungus residue Activated Carbon (EFAC) using the zinc chloride activation method at a 1 : 2 impregnation ratio and 600 °C activation for 3 hours.

Selective and enhanced adsorption of the monosubstituted benzenes on the Fe-modified MCM-41: Contribution of the substituent groups

The Fe-modified spherical meso-silica MCM-41 was synthesized via the base precipitation with Fe³⁺/urea, and the structure was characterized. Especially, the selective and enhanced adsorption characters and mechanism of the monosubstituted benzenes were investigated. The results showed that Fe modification increased the specific surface area of MCM-41 and retained the mesopore structure. Importantly, adsorption of the monosubstituted benzenes indicated that the adsorption behavior of the monosubstituted benzenes on the Fe-modified MCM-41 (Fe-MCM-41) was a monolayer adsorption on the heterogeneous surfaces, and it showed great selective adsorption towards aniline, and the maximum adsorption capacity of the Fe-MCM-41 towards aniline was 17.5 and 7.9 times of nitrobenzene and phenol. Additionally, the adsorption process and the isotherm of aniline conformed to the pseudo-second order kinetic mode and the Langmuir mode. The maximum adsorption capacity of the Fe-MCM-41 and the pure MCM-41 towards aniline were 17.9 and 1.9 mg g^-1, which indicated that the Fe modification significantly enhanced the adsorption capacity of MCM-41 towards aniline. Mechanism analysis reveals that the selective adsorption of the monosubstituted benzenes was attributed to the electron donating/withdrawing capacity of the substituent groups on benzene ring. Due to the electron withdrawing capacity of O atom, the exposed Fe atom of the ferric oxide loaded in the Fe-MCM-41 gave a strong electrophilic surface, which electrostatically interacted with the electron donating group (amino) in aniline.

Efficient removal of aniline by micro-scale zinc-copper (mZn/Cu) bimetallic particles in acidic solution: An oxidation degradation mechanism via radicals

Micro-scale zinc-copper (mZn/Cu) bimetallic particles were prepared via precipitating Cu on the surface of Zn and were for the first time applied in the aniline degradation. The results showed that the degradation efficiency of aniline was greatly related to the theoretical Cu mass loading and the initial pH. The optimal Cu loading and initial pH for the destruction of aniline were determined as 60.45 wt% and 3, respectively. To further assess the high reactivity of mZn/Cu, the removal of aniline and total organic carbon (TOC) was investigated in different systems. The degradation of aniline by mZn, mCu, and mZn + mCu was <5% within 75 min. However, 97% of aniline (10 mg L^-1) was decomposed and 47% of TOC was removed by mZn/Cu, both of which were more than three times as much as those by mFe/Cu. The mechanism investigations revealed that ^•OH radicals engendered from the reaction process are responsible for the rapid oxidative degradation of aniline. Furthermore, based on the analyses of the intermediates via LC-MS, the possible degradation pathways of aniline were proposed. Our findings suggested that mZn/Cu is a potential approach for aniline removal, which is different from the other bimetallic systems reported in the previous studies mainly as the reductive degradation.

Study of the Kinetics and Equilibrium of the Adsorption of Oils onto Hydrophobic Jute Fiber Modified via the Sol-Gel Method

A new kind of hydrophobic and oil sorbent based on jute fiber was successfully prepared by the integration of silica onto a fiber surface via the sol-gel method and subsequent hydrophobic modification with octadecyltrichlorosilane (OTS). Compared with the hydrophilic raw fiber, the modified fiber had a water contact angle (CA) of 136.2°, suggesting that the material has good hydrophobicity. Furthermore, the ability of oil in the oil/water system (taking diesel for example) to absorb was revealed by the kinetics, the isotherm equation, and the thermodynamic parameters. Adsorption behavior was kinetically investigated using pseudo first-order and pseudo second-order models. The data mostly correlated with the pseudo first-order model. The equilibrium adsorption at 298 K was assessed by using the Langmuir and Freundlich isotherm models. The Freundlich model had greater consistency with the experimental data. The obtained thermodynamic parameters demonstrate that the adsorption of diesel is spontaneous, favorable, and exothermic.

Adsorptive removal of organics from aqueous phase by acid-activated coal fly ash: preparation, adsorption, and Fenton regenerative valorization of "spent" adsorbent

Raw coal fly ash was activated to an adsorbent by sulfuric acid impregnation. The activation condition, the adsorption capacity, and the regenerative valorization of the adsorbent were studied. The results show that the optimal preparation conditions of the adsorbent are [H₂SO₄] = 1 mol L^-1, activation time = 30 min, the ratio of coal fly ash to acid = 1:20 (g:mL), calcination temperature = 100 °C. The adsorption of p-nitrophenol on the adsorbent accords with the pseudo-second-order kinetic equation and the adsorption rate constant is 0.089 g mg^-1 min^-1. The adsorption on this adsorbent can be considered enough after 35 min, when the corresponding adsorption capacity is 1.07 mg g^-1 (85.6% of p-nitrophenol removal). Compared with raw coal fly ash, the adsorbent has a stable adsorption performance at low pH range (pH = 1-6) and the adsorption of p-nitrophenol is an exothermic process. Ninety minutes is required for the regenerative valorization of saturated adsorbent by Fenton process. The regenerative valorization for this saturated adsorbent can reach 89% under the optimal proposed conditions (30 °C, pH = 3, [H₂O₂] = 5.0 mmol L^-1, [Fe²⁺] = 5.5 mmol L^-1). Within 15 experimental runs, the adsorbent has a better and better stability with the increase of experimental runs. Finally, the mechanism of activating coal fly ash is proposed, being verified by the results of the SEM and BET test.

Amine-functionalized magnetic bamboo-based activated carbon adsorptive removal of ciprofloxacin and norfloxacin: A batch and fixed-bed column study

Amine-functionalized magnetic bamboo-based activated carbon (AFM-BAC) derived from bamboo products wastes were employed for effective adsorption of fluoroquinolone antibiotics ciprofloxacin (CIP) and norfloxacin (NOR) through batch processing. The effects of factors on the adsorption of both antibiotics were studied. The studies of various factors influencing the adsorption behavior indicated that the maximum adsorption capacities for two antibiotics adsorption were observed in weakly acidic condition and the adsorption amounts of two antibiotics increased with the increase of zwitterionic form, implying the importance of zwitterionic form, and the adsorption process is spontaneous and endothermic. The result of date indicated that adsorption of both two antibiotics onto the AFM-BAC better fits Langmuir isotherm model. The saturated magnetization of AFM-BAC reached 8.55 emu g^-1. A fixed-bed column adsorption with a bench-scale was carried out. Desorption and regeneration experiments showed that the AFM-BAC for both antibiotics could remain above 80% after five consecutive recycling cycles.

Adsorption of pharmaceuticals in water through lignocellulosic fibers synergism

The contamination of water from disposal of drugs is an emerging problem due to their consequences on trophic webs. This study evaluated the ability of sugarcane and coconut fiber to reduce water toxicity contaminated by pharmaceuticals. The toxicity of solutions containing pharmaceuticals was studied by bioassay using Allium cepa, before and after filtration of contaminated water. The coconut and sugarcane fiber have not been satisfactory in reducing toxicity when tested separately. Despite no induction of chromosomal aberrations, our study found a reduction of the mitotic index. The mixture of fibers showed better results providing total reduction of toxicity, in addition to maintenance in the mitotic index and induction of chromosome aberrations. The interaction between fibers and drugs was confirmed by Thermogravimetry and Differential Thermal Analyses (TG/DTA) which presented differences in profile between the fibers before and after adsorption. The mixture of coconut and sugarcane proved viable for reduction of toxicity in contaminated water by a mixture of pharmaceuticals.

Layered double hydroxide intercalated with aromatic acid anions for the efficient capture of aniline from aqueous solution

Aniline is toxic and hard to be degraded, and thereby causes the environmental pollution seriously. Herein, a practical and green hydrothermal method was applied to fabricate terephthalic acid and pyromellitic acid intercalated layered double hydroxides (LDH) (named as TAL and PAL) for aniline efficient removal. The sorption of aniline on LDH-based materials were investigated at different experimental conditions, and the results indicated that aniline sorption on LDH, TAL and PAL were strongly dependent on pH and independent of ionic strength. The maximum sorption capacities of aniline on TAL and PAL at pH 5.0 and 293K were 90.4 and 130.0mg/g, respectively, which were significantly higher than that of aniline on LDH (52.6mg/g). Based on the BET, FTIR and XPS analysis, the higher sorption capacities of TAL and PAL were mainly due to high surface area and basal spacing as well as the abundant functional groups (e.g. -COO^-). The interactions of aniline with TAL and PAL were mainly dominated by hydrogen bonds and electrostatic interactions. Such a facile synthesis method, efficient removal performance and superior reusability indicated that the aromatic acid modified LDH materials had potential application for efficient treatment of organic pollutants in environmental pollution cleanup.

Hydrophobic functionalization of jute fabrics by enzymatic-assisted grafting of vinyl copolymers

Mechanism of grafting of vinyl monomers onto the lignin molecules of jute fabrics.

Removal of hexavalent chromium ions using CuO nanoparticles for water purification applications

Copper(II) oxide nanoparticles were synthesized at low temperature using cold finger assisted magnetron sputtering technique and were applied as adsorbent for the rapid removal of noxious Cr(VI) ions from the solvent phase. The average size of CuO nanoparticles from TEM analysis was found to be 8nm in addition to this the BET surface area (84.327m(2)/g) was found to be significantly high in comparison to the previously CuO nanoparticles synthesized via green route. The synthesized CuO nanoparticles is crystalline in nature and exhibits monoclinic phase, which was confirmed using various analytical techniques such as SAED, XRD and Raman analysis. The impact of influential parameters including pH, adsorbent dose, contact time, stirring speed, initial Cr(VI) ions concentration, and temperature were optimized using batch adsorption method in order to obtain maximum removal of Cr(VI) ions. From the thermodynamic parameters, the positive value of enthalpy (ΔH) and negative value of Gibbs free energy (ΔG) indicate the endothermic and spontaneous nature of Cr(VI) ions adsorption, respectively. The adsorption kinetics data was well fitted and found to be in good agreement with the pseudo second order kinetic behaviour.

Fast microwave-assisted preparation of a low-cost and recyclable carboxyl modified lignocellulose-biomass jute fiber for enhanced heavy metal removal from water

A low-cost and recyclable biosorbent derived from jute fiber was developed for high efficient adsorption of Pb(II), Cd(II) and Cu(II) from water. The jute fiber was rapidly pretreated and grafted with metal binding groups (COOH) under microwave heating (MH). The adsorption behavior of carboxyl-modified jute fiber under MH treatment (CMJFMH) toward heavy metal ions followed Langmuir isotherm model (R(2)>0.99) with remarkably high adsorption capacity (157.21, 88.98 and 43.98mg/g for Pb(II), Cd(II) and Cu(II), respectively). Also, CMJFMH showed fast removal ability for heavy metals in a highly significant correlation with pseudo second-order kinetics model. Besides, CMJFMH can be easily regenerated with EDTA-2Na solution and reused up to at least four times with equivalent high adsorption capacity. Overall, cheap and abundant production, rapid and facile preparation, fast and efficient adsorption of heavy metals and high regeneration ability can make the CMJFMH a preferred biosorbent for heavy metal removal from water.