Optimum Adsorption Conditions Research Articles

Targeted elimination of molybdenum ions from a leaching solution with the ability of radiated grafting GMA-PAN nanofibers

In this study, electrospun polyacrylonitrile nanofibers were effectively functionalized for enhanced molybdenum ion adsorption through a multi-step approach. Initially, glycidyl methacrylate was grafted onto the nanofibers via irradiation-induced grafting polymerization, followed by chemical modification with various amino groups, with triethylamine identified as the optimal modifier. The impacts of key synthesis parameters and reaction conditions on grafting level and adsorption capacity were thoroughly investigated, with a focus on achieving maximum efficiency. The resulting nanofibers were characterized using FTIR, SEM, and BET techniques, confirming the successful modification and structural features conducive to adsorption. Furthermore, a comprehensive experimental design, incorporating a central composite design, yielded optimal conditions for molybdenum adsorption, with key parameters including monomer concentration, irradiation dose, adsorbent mass, initial concentration, time, pH, temperature, and amine concentration. The adsorption kinetics were effectively described by the pseudo-second-order model, while the Langmuir isotherm model provided valuable insight into the adsorption behavior. Impressively, the adsorbent exhibited exceptional adsorption efficiency, surpassing 98% even after six adsorption–desorption cycles using 0.5 M HCl. Thermodynamic analysis revealed the exothermic nature of the adsorption process, along with decreased entropy and overall spontaneity, underlining the favorable conditions for molybdenum adsorption. Notably, the synthesized adsorbent demonstrated notable selectivity for molybdenum and achieved an impressive adsorption capacity of 109.79 mg/g, highlighting its potential for practical applications in molybdenum removal from aqueous solutions.

Cyanoremediation of heavy metals (As(v), Cd(ii), Cr(vi), Pb(ii)) by live cyanobacteria (Anabaena variabilis, and Synechocystis sp.): an eco-sustainable technology.

The cyanoremediation technique for heavy metal (HM) removal from wastewater using live cyanobacteria is promising to reduce the pollution risk both for the environment and human health. In this study, two widely recognized freshwater cyanobacteria, Anabaena variabilis and Synechocystis sp., were used to explore their efficacy in HM (As(v), Cd(ii), Cr(vi), Pb(ii)) removal. The different optimum adsorption conditions were pH 8 and 7.5 for A. variabilis and Synechocystis sp., respectively, but the temperature (25 °C) and contact time (48 hours) were the same for both strains. Under these specified conditions, A. variabilis exhibited the capability to remove 25% of As(v), 78% of Cd(ii), 54% of Cr(vi), and 17% of Pb(ii), whereas Synechocystis sp. removed 77% of As(v), 57% of Cd(ii), 91% of Cr(vi), and 77% of Pb(ii) at different initial concentrations. Metal diversity interfered negatively with cyanobacterial growth, especially Cd(ii) and As(v), as measured by OD730, dry biomass, chlorophyll a, and carotenoid production for both strains. Fourier transform infrared spectrum (FT-IR) analysis revealed the existence of diverse surface binding sites for HM adsorption, stemming from proteins and polysaccharides. Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) confirmed the presence of HMs on the surface of the cyanobacterial cells. Finally, the zeta potential results indicating alterations in the surface negative charges elucidated the adsorption mechanisms involved in the HM removal by both cyanobacteria. These results provided a comprehensive understanding of the HM adsorption mechanism by cyanobacteria, offering valuable theoretical insights that can be extrapolated to enhance our comprehension of the cyanoremediation mechanisms by various other cyanobacterial strains.

Extracting lignin from sugarcane bagasse for methylene blue and hexavalent chromium adsorption in textile wastewater: a facile, green, and sustainable approach.

This study presents the process of extracting lignin from sugarcane bagasse collected in the Mekong Delta, Vietnam by the alkali method. NaOH has been used as an effective, environmentally friendly chemical to enhance the extraction process. The obtained lignin was applied for methylene blue (MB) and hexavalent chromium (Cr(vi)) removal. Factors influencing lignin extraction and adsorption processes of MB and Cr(vi) were investigated, showcasing the sustainable reusability of lignin extracted from sugarcane bagasse. Lignin characterization was also carried out by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA) techniques. The results showed that the extracted lignin content reached 38.61% under optimal conditions (NaOH concentration of 10%, reaction temperature of 90 °C and reaction time of 90 min). The adsorption efficiency and capacity of lignin reached 90.90% and 9.09 mg g-1 for MB and 80.10% and 28.04 mg g-1 for Cr(vi), respectively, under optimum adsorption conditions (pH, adsorption time, initial methylene blue concentration, and used lignin content). The adsorption process obeyed Langmuir adsorption and was principally physical adsorption. These findings prove sugarcane bagasse based lignin as a cheap and efficient adsorbent for MB and Cr(vi) removal, which contributes to the utilization of the abundant agricultural by-product for wastewater treatment.

Defluoridation using pinecone-based activated carbon: Adsorption isotherm, kinetics, regeneration, and co-ions effect investigation

In this work, cheap and locally available pinecones of Pinus kiseya were used as a precursor to prepare activated carbon using single-step KOH activation for the removal of fluoride from water. The prepared activated car-bon?s BET surface area, and total pore volume, were determined as 972.13 m2 g-1 and 0.469 cm3 g-1, respectively. Batch adsorption studies were evaluated at different contact times, solution pH, adsorbent dose and concentration to obtain the optimum conditions for maximum adsorption. The adsorption data were fitted with the the isotherm models (Langmuir, Freundlich ad Temkin isotherm model) and the adsorption kinetic models. The experimental data were found to best fit using the Langmuir isotherm which confirmed the formation of a monolayer coverage with a maximum adsorption capacity of 2.845 m2 g-1. The adsorption kinetics was well described by the pseudo-second-order model. A study on the effects of co-existing ions showed that fluoride adsorption cap-acity was observed to decrease in the order: CO32- > SO42- > NO3- > Cl-. The regeneration studies were investigated to determine the reusability of the spent adsorbent. In summary, these findings demonstrated substantial evidence that the activated carbon can be prepared from P. kiseya cones as an eco-friendly adsorbent for the removal of ions such as fluoride from water.

Unlocking the valorization potential of Rooibos tea waste-derived activated carbon in the adsorptive removal of remazol brilliant blue R dye

In this work, we report the use of spent rooibos tea leaves to fabricate activated carbon and use it to adsorptively remove the toxic Remazol Brilliant Blue R (RBBR) from the aqueous solution. The resulting activated carbon (SRTLAC) was characterized by Brunauer-Emmett-Teller N2 adsorption/desorption for surface area analysis, scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray diffraction for morphological, functional group and crystallinity analyses. A Taguchi design approach was employed to determine the optimal conditions for the RBBR adsorption onto SRTLAC. Among the process variables studied, the sorbent dosage, initial concentration, and pH predominantly affected the removal capacity. The maximum removal of 246.5 mg/g was attained at the highest initial RBBR concentration of 120 mg/L, solution pH of 2, sorbent dosage of 20 mg, and agitation time of 110 min. The analysis of variance results showed that RBBR initial concentration contributed the most significant percentage (95.33 %) towards the removal uptake, highlighting its considerable impact. The adsorption data collected at various concentrations (20 – 120 mg/L) were modelled using three non-linear regression isotherms and kinetic models. The Langmuir isotherm model provided the optimal fit for adsorption, suggesting a monolayer and homogenous sorption system with a maximum capacity of 491.38 mg/g. Meanwhile, the pseudo-2nd order kinetic models accurately elucidated the sorption mechanism. The RBBR species interacted with the SRTLAC functional groups via hydrogen bonding, dipole-dipole interactions, and ion-dipole forces. Therefore, SRTLAC presents a powerful tool for ridding the environment of RBBR dye pollution.

Adsorbent performance of nipa (<i>nypafruticans</i>) frond in methylene blue dye degradation: Response surface methodology optimization

<abstract> <p>This study primarily focused on optimizing the performance of nipa (Nypafruticans)frond as an adsorbent for methylene blue (MB) dye, using the response surface methodology (RSM). The process of preparing nipafrond includes several key steps, such as washing, drying, and size reduction to 100 mesh. Subsequently, the adsorbent is activated using a 5%v/v HCl activator for 24 hours, and it is characterized by its functional groups using Fourier transform infrared spectroscopy (FT-IR). The composition of both the natural and activated nipa frond is examined through X-ray fluorescence (XRF), while the surface area of the samples is characterized using Brunauer-Emmett-Teller surface srea (BET) analysis. The adsorption characteristics are then tested as a function of two independent factors, including adsorbent mass (2.0, 3.0, and 4.0 g) and contact time (80–100 minutes), with an initial concentration of 50 mg/l MB. The statistical analysis, specifically analysis of variance (ANOVA), shows the substantial influence of these variables on the adsorption process. By applying the RSM model, the optimal conditions for MB adsorption are determined. These optimal conditions include nipa frond powder mass of 3.7071 g and a contact time of 83.1142 minutes, resulting in an optimum adsorption capacity of 2499 mg/g. The corresponding optimum adsorption efficiency is 99.7224%, with a desirability value of 0.974.</p> </abstract>

Nucleobase-Modified Microgels Synthesized via Microfabrication Technology for DNA Adsorption

DNA isolation is a crucial procedure since DNA-based assays have great importance in molecular biology, biochemistry and biomedical applications. The objective of this study is to fabricate micron-sized hydrogels as adsorbents for DNA. Poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) microgels were synthesized by free radical polymerization in the presence of N,N'-methylenebisacrylamide as a crosslinker, in the microholes of a microstencil array chip. Then, adenine was immobilized to microgels through the epoxy groups of glycidyl methacrylate. Scanning electron microscopy and Fourier transform infrared spectroscopy were employed to investigate the chemical and morphological characterizations of the microgels. The findings of the experiments demonstrate that the microgels had a cylindrical shape, were of uniform size, and had a height and diameter of around 500 μm. Observation of aromatic C=C peak confirmed the existence of adenine ligand in the microgel structure. Adsorption studies were carried out to determine the optimal conditions for DNA adsorption of nucleobase-immobilized microgels. After initially increasing, the quantity of DNA adsorbed onto the microgels reached a saturation level at a DNA concentration of around 2.0 mg/mL. The maximum adsorption was 38.54 mg/g microgels for an initial DNA concentration of 2.0 mg/mL in the optimum medium pH and temperature. DNA adsorption capabilities are shown to not significantly decline in recurrent adsorption-desorption cycles. As a result of the findings, adenine-immobilized microgels were demonstrated to be a viable option for DNA adsorption. Additionally, as a reference for future research, this study highlights the benefits of microfabrication technology, such as its simplicity of use in fabricating adsorption materials with the desired size, shape, and uniformity.

Response Surface Modelling and Optimization of Lead Adsorption from Wastewater Using Rice Husk Activated Carbon

Nigeria is renowned for its vast production of paddy rice, resulting in a significant volume of rice husk generation. Consequently, the conversion of these quantities of rice husk into beneficial applications is imperative to mitigate environmental pollution. The rice husk, procured from local millers in Zaria market, Nigeria, was subjected to thermal and chemical methods to produce activated carbon. The carbonization process involved heating at three different temperatures (300, 350 and 400 ℃) and subsequent mixing with 1M H3PO4 at a 1:2 ratio. Batch adsorption experiments were conducted, varying dosages of rice husk activated carbon (1 - 5 g), lead initial concentrations (10 - 60 mg/l), and carbonization temperatures (300 - 400 ℃). The Response Surface Methodology was utilized to model the adsorption capacities and removal efficiencies obtained. At carbonization temperature of 350 ℃, initial lead concentration of 60 mg/l, and adsorbent dosage of 3 g, the optimum removal efficiency and adsorption capacity 100% and 1.690 mg/g, respectively were observed. The veracity of the model equations was confirmed through the verification of the optimum adsorption conditions, with recorded percentage errors of 0.253% and 17.988%, for removal efficiency and adsorption capacity, respectively. The study's findings showed that rice husk activated carbon was highly effective in removing lead from wastewater. Furthermore, the model equations demonstrated reliability in forecasting the responses, and the optimum conditions were deemed valid.

Reusable environmentally friendly electrospun cellulose acetate/cellulose nanocrystals nanofibers for methylene blue removal

Cellulose based nanofibers were developed by electrospinning cellulose acetate (CA) with cellulose nanocrystals (CNC) for efficient removal of methylene blue (MB) dye. The incorporation of 25% (CA-CNC 25%) and 50% CNCs (CA-CNC 50%) improved the physical and chemical properties of CA in the formed nanofibers. Adsorption at an alkaline pH of 10.5 induced deacetylation that enhanced adsorption and reusability of CA-CNC 50%, whose MB adsorption capacity was double that of neat CA. The optimum adsorption conditions using CA-CNC 50% were pH of 10.5 at 40 °C for 5 h, with an initial MB concentration of 25 mg/L. The maximum adsorption capacity of the optimized CA-CNC 50% at 1000 mg/L initial MB concentration was 316.6 mg/g. The CA-CNC 50% maintained MB removal of ≥ 80% for up to 5 cycles. Theoretical modeling and experimental data suggest that the adsorption of MB onto CA-CNC 50% can be described as endothermal chemisorption with pore diffusion being the rate-limiting of the dye mass transfer. The possible interactions that contributed to MB adsorption onto CA-CNC 50% are π-π stacking, electrostatic attraction, and hydrogen bonding, the latter of which came into effect at the onset of deacetylation.

Reshaping environmental sustainability: Poultry by-products digestate valorization for enhanced biochar performance in methylene blue removal

Anaerobic digestion is a highly effective and innovative method for treating organic waste while simultaneously generating energy. However, the treatment of the resulting digestate remains a challenging endeavor. To address this issue, poultry by-products digestate is used in this study to prepare biochars at two different pyrolysis temperatures (500/600 °C). Despite their potential, the utilization of untreated biochar is restricted due to its inadequate adsorption capacity. Therefore, each biochar was chemically activated using either HNO3 or KOH to synthesize four activated biochars (BC5@KOH, BC6@HNO3, BC5@HNO3, and BC6@HNO3). The aim is to investigate how the nature of chemical activation and pyrolysis temperature influence the adsorption of methylene blue dye. Characterization techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), Raman analysis, and pHpzc determination, were exploited to comprehensively elucidate the structure and composition of both unprocessed and chemically activated biochars. Among the activated biochars, the adsorbent BC5@HNO3 exhibits the highest methylene blue (MB) adsorption capacity, reaching 101.72 mg.g−1 at 298 K under (pH = 2, ads dose = 0.6 g.L−1, shaking time of 20 min, as optimal conditions for MB adsorption. Adsorption data for each adsorbent strongly aligns with both the Langmuir isotherm model and the pseudo-second-order kinetic model. Moreover, the thermodynamic study reveals that the adsorption process was endothermic and spontaneous. The adsorption mechanism of MB dye was explored using various analytical techniques, including FTIR, SEM, PZC, and pH impact assessment. The findings suggest correlations with electrostatic interactions, hydrogen bonding, pore filling, as well as n-π and π-π interactions. Apparently, activated biochars play a crucial role in efficiently removing methylene blue dye, showcasing their potential as environmentally friendly and effective adsorbents.

Adsorption of Cu(II) from Aqueous Solution on Sonicated Activated Carbon Prepared from Arenga Pinnata Merr Fruit Shell Waste: Isotherm, Kinetic and Thermodynamic Studies

Adsorption of Cu(II) from aqueous solution on the activated carbon (AC) prepared from Arenga pinnata Merr fruit shell (APMFS) waste with the assistance of ultrasound was evaluated by conducting batch mode experiments. As a result, KOH activation using 40 kHz of ultrasound restructured active binding sites and produced more pores on the APMFS-AC according to FT-IR and SEM analyses, respectively. Increasing the sonication time from 45 min to 135 min increased the adsorption capacity from 6.535 mg/g to 7.042 mg/g, respectively, at the initial Cu(II) concentration of 257.213 mg/L, 27°C and pH 5. With an increment of the adsorption temperature to 45°C, it increased the adsorption capacity up to 11.765 mg/g. The investigation on the independent variables showed the optimum conditions of adsorption which were 257.213 mg/L of the initial Cu(II) concentration, 60 min of contact time, pH 5 and 45°C using 135 min of sonicated APMFS-AC. The Cu(II) adsorption isotherm was fitted with the Langmuir model at the optimum condition. The Langmuir mono-layer adsorption capacity obtained was 11.765 mg/g with the BET saturation capacity, and the total pore volume values were 13.029 mg/g and 3.987 L/mg, respectively. The Cu(II) adsorption followed the pseudo second-order kinetics model with the adsorption rate 0.473 g/mg.min. Thermodynamic parameters of enthalpy change (∆H0, 27.035 kJ/mol), Gibbs free energy (∆G0, 7.292 kJ/mol), entropy change (∆S0, 0.062 kJ/mol.K), and activation energy (E, 22.637 kJ/mol) were determined. These results confirmed that endothermic, spontaneous and chemical adsorption took place.

Removal of two antidepressant active pharmaceutical ingredients from hospital wastewater by polystyrene-coated magnetite nanoparticles-assisted batch adsorption process.

This study employed simple polystyrene-coated magnetite nanoparticles (PS@MNPs)-assisted batch adsorption process for the removal of two antidepressant active ingredients (amitriptyline HCl and sertraline HCl) from hospital wastewater. Dominant parameters of the adsorption process including pH, adsorbent amount, and contact period were optimized through the univariate approach to enhance the adsorption efficiency. Upon reaching optimum adsorption conditions, equilibrium experiments were performed by spiking the adsorbates in hospital wastewater in the concentration range of 100-2000 μg/L. The concentrations of the adsorbates in the effluent were calculated using the matrix-matching calibration strategy to enhance the accuracy of quantification. A validated switchable solvent-based liquid phase microextraction (SS-LPME) method was employed to enrich the two active pharmaceutical ingredients (APIs) prior to sensitive determination with GC-MS (gas chromatography-mass spectrometry). The equilibrium data were mathematically modeled employing the Langmuir and Freundlich adsorption isotherm models. The isotherm constants were calculated, and the results showed that both the isotherm models fitted well with the experimental data. The efficient and simple batch adsorption strategy reported in this study was successfully employed to remove amitriptyline HCl and sertraline HCl from hospital wastewater at low concentrations.

Comprehensive Evaluation of Polyaniline-Doped Lignosulfonate in Adsorbing Dye and Heavy Metal Ions.

Lignosulfonate/polyaniline (LS/PANI) nanocomposite adsorbent materials were prepared by the chemical polymerization of lignosulfonate with an aniline monomer as a dopant and structure-directing agent, and the adsorption behavior of dyes as well as heavy metal ions was investigated. LS/PANI composites were used as dye adsorbents for the removal of different cationic dyes (malachite green, methylene blue, and crystal violet). The adsorption behavior of LS/PANI composites as dye adsorbents for malachite green was investigated by examining the effects of the adsorbent dosage, solution pH, initial concentration of dye, adsorption time, and temperature on the adsorption properties of this dye. The following conclusions were obtained. The optimum adsorption conditions for the removal of malachite green dye when LS/PANI composites were used as malachite green dye adsorbents were as follows: an adsorbent dosage of 20 mg, an initial concentration of the dye of 250 mg/L, an adsorption time of 300 min, and a temperature of 358 K. The LS/PANI composite adsorbed malachite green dye in accordance with the Langmuir adsorption model and pseudo-second-order kinetic model, which belongs to chemisorption-based monomolecular adsorption, and the equilibrium adsorption amount was 245.75 mg/g. In particular, the adsorption of heavy metal ion Pb2+ was investigated, and the removal performance was also favorable for Pb2+.

Magnetic Fe3O4-grafted cellulose/graphene oxide nanocomposite for methylene blue removal from aqueous solutions: Synthesis and characterization

This research focuses on the development of efficient and cost-effective methods for the treatment of industrial wastewater. Magnetic Fe3O4 cellulose/graphene oxide nanocomposite was synthesized through free radical graft copolymerization of acrylic acid (AA) and acrylamide (AM) on the cellulose chains. The grafting copolymerization parameters, including molar ratio, temperature, and reaction time, were optimized. Structural characteristics of the prepared samples were analyzed using FT-IR, XRD, and VSM techniques, while morphological characteristics were examined using FE-SEM and HR-TEM. The prepared samples were evaluated for their adsorption capacity towards methylene blue (MB) dye under various conditions. The factors controlling the adsorption process, such as pH, contact time, adsorbent dose, and initial MB concentration, were studied. The experimental data were successfully described by the pseudo-second-order model, and the equilibrium adsorption results fitted the Freundlich and Dubinin-Radushkevich isotherms. Thermodynamic studies revealed that the adsorption process was endothermic and occurred spontaneously, leading to greater disorder. Optimal conditions for MB adsorption onto the magnetic cellulose/graphene oxide nanocomposite were determined to be pH 7, a contact time of 7 h, and an adsorbent dose of 0.0375 g in a 30 mg/L dye solution. The inclusion of magnetite and graphene oxide into cellulose resulted in enhanced removal efficiency of the dye, with the magnetic cellulose/graphene oxide nanocomposite exhibiting a removal percentage of 97%. These findings demonstrate the potential of the magnetic cellulose/graphene oxide nanocomposite as a powerful adsorbent for the removal of methylene blue dye from aqueous solutions, offering promising prospects for the treatment of industrial wastewater.

Modelling and Optimization of Methylene Blue Adsorption Process on Leonurus cardiaca L. Biomass Powder

The main objective of this study was to optimize the adsorption process of methylene blue on a natural, low-cost adsorbent, Leonurus cardiaca L. biomass powder, in order to maximize dye removal efficiency from aqueous solutions. For this purpose, the Taguchi method was used based on an L27 orthogonal array design considering six controllable factors at three levels. The percentage contribution of each factor was computed using analysis of variance (ANOVA). The optimal adsorption conditions were established. The experimental data from equilibrium and kinetic studies were modelled using specific equilibrium isotherms and kinetic models. Thermodynamic parameters were calculated in order to determine the main adsorption mechanism. The obtained results showed that the ionic strength is the factor that most influences dye adsorption (percentage contribution 72.33%), whereas the adsorbent dose had the least impact. The Sips isotherm and the general kinetic model most accurately characterized the process. The maximum adsorption capacity 103.21 (mg g−1) indicated by the Sips isotherm and the equilibrium time (40 min) were better compared to the values obtained for other bio-adsorbents used for methylene blue adsorption. The main mechanism involved in the adsorption is physisorption, while chemisorption only contributes marginally to the process.

Tannic acid adsorption properties of cellulose nanocrystalline/fish swim bladder gelatin composite sponge

Foods and beverages with excessive tannins acid (TA) content taste astringent and bitter. The overconsumption of TA could result in nutritional and digestive problems. In this study, the cellulose nanocrystals (CNC)/fish swim bladder gelatin (FG) composite sponge was prepared with glutaraldehyde as a crosslinking agent. The TA adsorption performance of the sponge was discussed. The freeze-dried CNC/FG composite sponge had a porous network structure. CNC was combined into the FG matrix as a reinforcing phase. The mechanical strength, thermal stability, and swelling properties of the composite sponge were improved with the addition of an appropriate amount of CNC. Although CNC decreased the porosity of composite sponge, the increase in active adsorption sites resulted in an overall positive effect on its TA adsorption properties. Under the optimal adsorption conditions, the TA removal rate of 1.0 % CNC composites reached 80.4 %. Furthermore, the sponge retained a TA removal rate of 54 % after five cycles of adsorption and desorption using 50 % ethanol. The results demonstrated that CNC/FG composite sponge has application potential in the field of adsorption materials for TA.

Crystal violet removal using ZIF-60: Batch adsorption studies, mechanistic & machine learning modeling

This study, for the first time, reported the utilization of ZIF-60 for the adsorptive removal of organic pollutant from contaminated water. Characterization techniques were used to confirm the synthesis of ZIF-60 adsorbent which was then used to study the uptake of crystal violet (CV) from the aqueous system. A remarkably high experimental uptake (in excess of 7000 mg/g) of CV onto ZIF-60 was noted which was due to the careful selection of process parameters while conducting the batch adsorption studies. Response surface methodology technique was utilized as the tool for response optimization and for studying the effect of varying adsorption process parameters. Temperature had the most significant influence on CV adsorption followed by CV concentration, ZIF-60 dose and pH. Adsorption kinetics and isotherm investigations were conducted based on the optimized adsorption conditions, and the obtained good data fitting with more than one model suggests an intricate adsorption process. On the other hand, the thermodynamic studies revealed a highly endothermic and spontaneous process. The post adsorption analysis revealed π-π stacking interaction as the dominant force driving the uptake of CV onto ZIF-60. Additionally, several machine learning models that were based on distinct algorithms were utilized for the prediction of CV adsorption onto ZIF-60. An ensemble model that was based on the combination of several optimized models was created using the voting technique; this model proved to be the most accurate in predicting the CV uptake by ZIF-60 as suggested by its superior value for several evaluation metrics.

Electric double layer capacitive adsorption and faradaic pseudo-capacitance behavior of ZnFe-PANI/CNT electrode for phosphate removal in capacitive deionization

Capacitive deionization technology possesses puissant competitiveness in the field of water treatment due to its low cost and high efficiency. In this study, polyaniline (PANI) doped and carboxyl intercalated metal hydroxide composite (ZnFe-PANI/CNT) was developed by a simple co-precipitation method, and used as anode electrode for phosphate removal in sewage. The results show that ZnFe-PANI/CNT electrode can efficiently remove phosphate at concentration of 2–10 mg/L at a wide range of pH (3–10) by electric double layer capacitive adsorption and pseudocapacitive adsorption. The concentration of phosphate in the effluent was as low as 0.095 mg/L, and the coexisting anions (Cl−, NO3−, SO42− and HCO3−) hardly inhibited the phosphate adsorption by ZnFe-PANI/CNT composite electrode. In addition, under the optimal phosphate adsorption conditions (pH = 7 and applied voltage of 1.2 V), the energy consumption of CDI system was calculated as low as 0.00274 kWh/g P and 0.017 kWh/m3 water, realizing the expectation of low cost and high efficiency operation.

Adsorption Of Methylene Blue Using Active Charcoal From Empty Fruit Bunch (EFB)

Research on the adsorption of methylene blue by activated charcoal from Empty Fruit Bunch (EFB) has been carried out. This study aimed to synthesize activated charcoal from EFB, characterize it, and use it as an adsorbent for methylene blue. Activated charcoal was synthesized by carbonation in a furnace at 300oC for 1 hour. Chemically, activation was carried out by immersion in HCl solution for 24 hours. Characterization was carried out by proximate test, determination of functional groups using Fourier Transform Infrared (FT-IR), and determining material shape with X-Ray Diffraction (XRD). The study of activated charcoal adsorption as methylene blue adsorbent was carried out by treating variations in contact time, adsorbent weight, and concentration. The results of the proximate test with the parameters of surface area, moisture content, and ash content were 162.12 m2/g, 0.52%, and 5.27%, respectively. The results of the FT-IR characterization test showed an aromatic C–H, C=C and C–O. Based on the results of characterization with XRD giving a pattern at a diffraction angle of 2 20 - 30o, it was seen that there was a wide peak, which indicated that it had an amorphous structure. The optimum conditions for methylene blue adsorption occurred at a contact time of 40 minutes, and the adsorbent weight was 0.1 g for 10 mL of 50 ppm methylene blue. The adsorption of methylene blue followed the Freundlich isotherm adsorption pattern and had a maximum adsorption capacity of 8.92 mg/g.

Functional Ag-EDTA-modified MnO2 nanocoral reef for rapid removal of hazardous copper from wastewater

A novel MnO2@EDTA-Ag nanocoral reef was constructed via a simplified redox reaction followed by EDTA and Ag nanoparticles impregnation to capture hazardous copper (II) from wastewater. A comprehensive characterization of the synthesized materials was conducted. The morphology of MnO2@EDTA-Ag in the form of a nanocoral reef was constructed of two-dimensional nanoplatelets and nanorod-like nanostructures. The optimal adsorption conditions proposed by the Plackett–Burman design (PBD) that would provide a removal % of 99.95 were pH 5.5, a contact time of 32.0 min, a Cu(II) concentration of 11.2 mg L−1, an adsorbent dose of 0.05 g, and a temperature of 40.3 °C. The loading of Ag nanoparticles onto MnO2@EDTA improved the adsorption capability of MnO2@EDTA-Ag. Additionally, the recyclability of MnO2@EDTA-Ag nanocoral reef was maintained at 80% after three adsorption–desorption cycles, and there was no significant change in the XRD analysis before and after the recycling process, implying its stability. It was found that nanocoral reef-assisted EDTA formed a chelation/complexation reaction between COO− groups and C–N bonds of EDTA with Cu(II) ions. In addition, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis proved the synergistic effect of the electrostatic interaction and chelation/complexation was responsible for the removal mechanism of Cu(II). Also, the results demonstrated no significant variation in MnO2@EDTA-Ag removal efficiency for all the tested real water samples, revealing its efficacy in wastewater treatment. Therefore, the current study suggests that MnO2@EDTA-Ag has substantial potential to be used as a feasible adsorbent for probable hazardous metals remediation.