Adsorption Of MB Research Articles

Preparation of coal tar pitch based adsorption materials: Understanding the adsorption mechanism by combining field energy theory and statistical physics models

A coal tar pitch based adsorbent(CTPA) was prepared. The structure of the CTPA adsorbate was analyzed using FTIR, Zeta potential, SEM and BET. We investigate the adsorption mechanism of cation dye contaminants by adsorbates. It has been shown that CTPA has superior adsorption properties for MB. Thermodynamic analysis and Zeta potential analysis have shown that electrostatic forces play a particularly prominent role in adsorption. Statistical physics model studies have shown that increasing the temperature increases the trapping power and the number of adsorption sites. According to the SED theory, MB adsorption is particularly strong at elevated energy sites.

Magnetic Ionotropic Hydrogels Based on Carboxymethyl Cellulose for Aqueous Pollution Mitigation

In this work, stabilized ionotropic hydrogels were designed using sodium carboxymethyl cellulose (CMC) and assessed as inexpensive sorbents for hazardous chemicals (e.g., Methylene Blue, MB) from contaminated wastewaters. In order to increase the adsorption capacity of the hydrogelated matrix and facilitate its magnetic separation from aqueous solutions, sodium dodecyl sulfate (SDS) and manganese ferrite (MnFe2O4) were introduced into the polymer framework. The morphological, structural, elemental, and magnetic properties of the adsorbents (in the form of beads) were assessed using scanning electron microscopy (SEM), energy-dispersive X-ray analysis, Fourier-transform infrared spectroscopy (FTIR), and a vibrating-sample magnetometer (VSM). The magnetic beads with the best adsorption performance were subjected to kinetic and isotherm studies. The PFO model best describes the adsorption kinetics. A homogeneous monolayer adsorption system was predicted by the Langmuir isotherm model, registering a maximum adsorption capacity of 234 mg/g at 300 K. The calculated thermodynamic parameter values indicated that the investigated adsorption processes were both spontaneous (ΔG < 0) and exothermic (ΔH < 0). The used sorbent can be recovered after immersion in acetone (93% desorption efficiency) and re-used for MB adsorption. In addition, the molecular docking simulations disclosed aspects of the mechanism of intermolecular interaction between CMC and MB by detailing the contributions of the van der Waals (physical) and Coulomb (electrostatic) forces.

Development and optimization of geopolymer adsorbent for water treatment: Application of mixture design approach

The current paper refers to the study of a new approach to optimizing the adsorptive properties of geopolymers by varying the aluminosilicate precursors from kaolin (K), metakaolin (MK), and coal fly ash (CFA) as internal synthesis factors. The simplex-augmented-centroid mixture design was applied to identify the optimal formulation from the three aluminosilicate precursors to develop a geopolymer (GP) with a distinctive structure that positively affects its dye adsorption efficiency. The variously formulated GP samples were tested for the removal of both methylene blue (MB-dye) and crystal violet dye (CV-dye) from an aqueous solution. The mathematical-statistical analysis of the experimental readings suggested that the generated special cubic models were significant, and thus the chosen approach was adequate for determining the optimum blending proportion. The optimization tools indicated that the optimal mixture from the three aluminosilicate precursors for developing a GP with high adsorption efficiency was 58% MK, 42% K, and 0% CFA. The optimized geopolymer (GPO) was synthesized and then analyzed using a variety of physicochemical techniques, which revealed the presence of an amorphous N-A-S-H gel-rich porous structure as an influencing property on the geopolymer's organic dye adsorption efficiency. The dependence of the adsorption mechanism of both MB-dye and CV-dye by GPO on the adsorbent dosage, contact time, initial dye concentration, temperature, and solution pH was evaluated. The isothermic and kinetic experimental readings for MB and CV-dyes adsorption by GPO were well fitted to the pseudo-second-order and Freundlich models, with an exothermic, favorable, and spontaneous adsorption reaction thermodynamically. The experimental studies in the lab scale on GPO produce comparable results. From these results, it has been concluded that the accuracy and feasibility of the mixture design simulation succeeded in optimizing and developing a geopolymeric sorbent material with great potential as an excellent economical agent for removing cationic dyes from aqueous media. This point represents an added value compared to traditional non-optimized geopolymer absorbents. Besides, this geopolymer material represents a significant application possibility for water treatment and remediation of hazardous dye pollutants.

Isotherm, kinetics, thermodynamics, recyclability and mechanism of ultrasonic assisted adsorption of methylene blue and lead (II) ions using green synthesized nickel oxide nanoparticles

One of the urgent global problems demanding effective mitigation strategies is the pollution caused by organic dyes and metal ions like methylene blue and lead (II) ions. In recent times, the increasing applications of nickel oxide nanoparticles in biomedicine, catalysis, sensors in optoelectronic materials, and the prevention of environmental pollution have attracted researchers' interest across the globe. Herein, Psidium guajava leaves extract was utilized to synthesize green nickel oxide nanoparticles (PG-NiONPs). Surface and analytical techniques were employed to characterize PG-NiONPs and were thereafter applied to remove methylene blue and lead (II) ions from wastewater. The results revealed the quantified presence of phytochemicals such as alkaloids, phenols, tannins, flavonoids and saponins in the Psidium guajava leaves extract. The prepared PG-NiONPs revealed a crystalline phase, functional groups, mesoporous and microstructural arrangements typical of nickel oxide nanoparticles. The surface area of PG-NiONPs was obtained as 85.40 m2/g. The best ultrasonic-assisted adsorption of MB and Pb(II) ions was achieved at pH values of 6 and 5 for MB and Pb(II), a contact time of 60 min, an adsorbent mass of 40 mg/L, and a temperature of 50 °C, respectively. The maximum MB and Pb(II) adsorption capacities of 495.58 and 508.56 mg/g were evaluated. The experimental data corroborated with the pseudo-second-order and Toth isotherm models. The adsorption of MB and Pb(II) over green PG-NiONPs was a thermodynamically spontaneous process. The PG-NiONPs indicated good recyclability with high stability even after 8 adsorption cycles. Overall, the PG-NiONPs is a potential adsorbent for improved toxic dyes, metal ions and other scavengers removal from wastewater.

Collaborative impact of Cu/TiO2 nano composites for elimination of cationic dye from aqueous solution: Kinetics and isothermal modeling

Nano TiO2 is economic nano particles have many applications. This study focus on evaluation of Cu/TiO2 nano composites mechanically prepared for elimination of methylene blue dye (MB) in its aqueous solutions. Two molar ratios of TiO2 to Cu were used for the fabricated nano composites; (1:1)(TC1) and (2:1)(TC2). The fabricated doped particles were characterized by N2 adsorption–desorption isotherm, (FTIR) and (SEM/ EDAX) techniques. The results clarify that Cu atoms were randomly covered or precipitated on TiO2 nano particles resulting to increase in the porosity and surface roughness. The uptake study was conducted via batch mode under various processing parameters like pH, contact time, initial dye concentration and adsorbent mass. The results revealed that, maximum uptake 77–90 mg/g was achieved at solution pH = 5 for TiO2 and pH = 7 for doped TiO2 with an equilibrium time 6 h for studied samples. Removal % was in order TC1 > TC2 > T which correlated to the amount of deposited Cu in nano composites. Besides, the adsorption capacity increased by increasing the adsorbent mass and much reduced by boosting the dye concentration. This is explained due to the electrostatic interaction between benzene ring in MB and the electron cloud of Cu molecules. Pseudo 2nd order kinetic model was more appropriate to describe the adsorption of MB onto doped TiO2 nano particles and the experimental data were more fitting to Freundlich model suggesting a heterogeneous adsorption.

Temperature-regulated formation of hierarchical pores and defective sites in MIL-121 for enhanced adsorption of cationic and anionic dyes

The micropore range of typical MOFs limits the accessibility of substances e.g., dyes have larger sizes. In this work, MIL-121 was transformed into hierarchically porous MOF variants through temperature-regulated linker thermolysis, of which hierarchical porosity (increased average pore size of up to 61.8 Å) and increased specific surface area of up to 346.2 m2/g were achieved. Surface functionality of –COOH and anhydride groups were also improved together with the formation of defective sites and graphite carbon with π-conjugated layers. Improved adsorption of CR and MB were observed with the thermally treated variants, in particular for MIL-121-500 (597.9 and 246.0 mg/g, respectively), when compared with pristine MIL-121 (69.7 and 27.8 mg/g, respectively). Pseudo-second order and Langmuir models were used to explain the adsorption mechanisms. Thermodynamic studies revealed the adsorption of CR and MB on MIL-121-500 were spontaneous, and were endothermic and exothermic, respectively. Characterization of the adsorbents and the DFT calculations demonstrated the synergetic effect of the improved textural and functional properties (especially the oxygen defective sites) of MIL-121-500 was responsible for the enhanced adsorption of dyes. This work sheds light on improving the adsorption performance of MOFs to organic dyes through linker thermolysis and offering a systematic approach to designing custom-built MOFs for targeted applications.

Adsorption of anionic and cationic dyes in aqueous solution by a sustainable and low-cost activated carbon based on argan solid waste treated with H3PO4

The objective of this work is to study the adsorption capacity of a natural and low-cost material prepared from argan waste treated with H3PO4 towards two dyes of different molecular charges and presenting an acute toxicity, the methyl orange (MO, anionic dye) and the methylene blue (MB, cationic dye). The prepared adsorbent was characterized by SEM, EDX, FTIR, and BET specific surface. These analyses showed the presence of C (42%), O (55%), and P (3%) and a remarkable difference between the morphology of the precursor and that of the obtained material with a specific surface of 475 m2/g and a very porous structure as well as the main functional groups, O-H, C=O, and C-H. The influence of the pH showed a maximum adsorption at pH =2 for MO and at pH = 10 for MB. Investigation of the effect of time on the adsorption of anionic and cationic dyes revealed that the contact time at equilibrium was 240 and 180 min, respectively. The isotherms that best fit the adsorption of MO and MB are the Langmuir model and the Freundlich model respectively. The kinetic study showed that the experimental data are in agreement with the pseudo-second-order model. Regeneration of the saturated material was also studied for the probability of reusing the adsorbent in many experiments. The valorization of argan waste into activated carbon using H3PO4 has allowed to obtain an effective adsorbent for the removal of anionic and cationic dyes and create an added value for environmental sustainability.

Characterization and applicability of the natural Iraqi bentonite clay for toxic cationic dye removal: Adsorption kinetic and isotherm study

This research targets to adsorb the organic dye (methylene blue, MB) from aqueous media using natural Iraqi bentonite clay (NIBC). Several analytical methods (e.g., XRD, FTIR, SEM-EDX, XRF, pHpzc, and BET) analysis were conducted to inspect the physicochemical characteristics of the NIBC. Adsorption key variables, including dosage of adsorbent (0.02–0.1 g), pH (2–10), and initial concentrations (10–150 mg/L) were inspected for determining their impacts on MB dye removal. The Redlich-Peterson isotherm demonstrated the best account for the equilibrium adsorption of MB. The NIBC's highest adsorption capacity (qmax) for MB was 256 mg/g. The kinetics of the adsorption of MB by NIBC matched the pseudo-second-order model. This study demonstrates that the NIBC could be utilized to successfully remove MB from aqueous environments.

Novel 3D sphere-like β-In2S3/Biochar nanoflowers for remediation of dyes in single and binary systems and interpretation using statistical physical modeling

A novel 3D sphere-like β-In2S3/Biochar nanoflowers have been fabricated through the solvothermal process for effectively removing cationic malachite green and methylene blue dye in both single and binary systems. XRD, SEM, EDX, Elemental Mapping, TEM, BET, XPS, and FT-IR were used to characterize the physical and chemical properties of β-In2S3/Biochar. It was found that MG and MB had an adsorption capacity of 636.94 mg/g and 625.02 mg/g for β-In2S3/Biochar in single systems, while in binary systems, they had an adsorption capacity of 564.97 and 438.58 mg/g, respectively. The adsorption capacities in the multicomponent system were calculated using the extended Langmuir modeling, and the kinetic behavior of the adsorption in both systems followed pseudo-second-order kinetics. From the statistical physical modeling, the nD parameter values for MG adsorption obtained were 0.468, 0.498, and 0.612 at 298, 308, and 318 K, and the nD parameter values for MB adsorption were 0.63, 0.833, and 0.896, respectively in the single systems. These results showed that the dyes were adsorbed in a parallel orientation, and the adsorption followed a multi-interaction mechanism. The effect of water matrices and competing species, such as organic and inorganic compounds, are also investigated to find potential applications in real wastewater. In addition, the decrease in adsorption capacity for both dyes in the binary system was credited to the antagonistic effect, and the high efficiency and reusability of the fabricated β-In2S3/Biochar might provide new ideas for developing competent adsorbents to remove dyes from wastewater.

Study on Amino-functionalized Porous Carbon Materials for MB and Cr(VI) Adsorption

From the perspective of environmental protection, high removal rate, reusable and degradable, amino-functionalized porous hydrogel material P-(EA-β-CD/KHA/AC) was synthesized by introducing ethylamino cyclodextrin, humic acid, and activated carbon, using polyacrylic acid as the carrier. MB and Cr (VI) are common wastewater pollutants, thus, Such contaminants must be removed from the water. The gel materials before and after adsorption were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The removal of MB and Cr(VI) showed high adsorption capacity. At 298 K and pH 8, the adsorption capacities of P-(EA-β-CD/KHA/AC) hydrogel for MB and Cr(VI) were as high as 262.31 and 170.12 mg/g, respectively, and the removal rates were 98.96% and 70.27%, respectively. The adsorption behavior follows the pseudo-second-order kinetic equation, conforming to the Langmuir model; and through intermolecular forces, π–π conjugation, chelation, and other interactions, entropy-increasing, endothermic, and spontaneous process is formed. The regeneration and degradability experiments of P-(EA-β-CD/KHA/AC) hydrogel were conducted and its recycling performance was verified.

Tropical fruit wastes including durian seeds and rambutan peels as a precursor for producing activated carbon using H3PO4-assisted microwave method: RSM-BBD optimization and mechanism for methylene blue dye adsorption

Herein, tropical fruit biomass wastes including durian seeds (DS) and rambutan peels (RP) were used as sustainable precursors for preparing activated carbon (DSRPAC) using microwave-induced H3PO4 activation. The textural and physicochemical characteristics of DSRPAC were investigated by N2 adsorption-desorption isotherms, X-ray diffraction, Fourier transform infrared, point of zero charge, and scanning electron microscope analyses. These findings reveal that the DSRPAC has a mean pore diameter of 3.79 nm and a specific surface area of 104.2 m2/g. DSRPAC was applied as a green adsorbent to extensively investigate the removal of an organic dye (methylene blue, MB) from aqueous solutions. The response surface methodology Box–Behnken design (RSM-BBD) was used to evaluate the vital adsorption characteristics, which included (A) DSRPAC dosage (0.02–0.12 g/L), (B) pH (4–10), and (C) time (10–70 min). The BBD model specified that the DSRPAC dosage (0.12 g/L), pH (10), and time (40 min) parameters caused the largest removal of MB (82.1%). The adsorption isotherm findings reveal that MB adsorption pursues the Freundlich model, whereas the kinetic data can be well described by the pseudo-first-order and pseudo-second-order models. DSRPAC exhibited good MB adsorption capability (118.5 mg/g). Several mechanisms control MB adsorption by the DSRPAC, including electrostatic forces, π–π stacking, and H-bonding. This work shows that DSRPAC derived from DS and RP could serve as a viable adsorbent for the treatment of industrial effluents containing organic dye.

Carboxymethyl cellulose/sodium alginate beads incorporated with calcium carbonate nanoparticles and bentonite for phosphate recovery

Although anionic polyelectrolyte hydrogel beads offer attractive adsorption of cationic dyes, phosphate adsorption is limited by electrostatic interactions. In this work, carboxymethyl cellulose (CMC)/sodium alginate (SA) hydrogel beads were modified with calcium carbonate (CaCO3) and/or bentonite (Be). The compatibility between CaCO3 and Be was proven by the homogeneous surface, as shown in the scanning electron microscopic images. Fourier-transform infrared and X-ray diffraction spectra further confirmed the existence of inorganic filler in the hydrogel beads. Although CMC/SA/Be/CaCO3 hydrogel beads attained the highest methylene blue and phosphate adsorption capacities (142.15 MB mg/g, 90.31 P mg/g), phosphate adsorption was significantly improved once CaCO3 nanoparticles were incorporated into CMC/SA/CaCO3 hydrogel beads. The kinetics of MB adsorption by CMC/SA hydrogel beads with or without inorganic fillers could be described by the pseudo-second-order model under chemical interactions. The phosphate adsorption by CMC/SA/Be/CaCO3 hydrogel beads could be explained by the Elovich model due to heterogeneous properties. The incorporation of Be and CaCO3 also improved the phosphate adsorption through chemical interaction since Langmuir isotherm fitted the phosphate adsorption by CMC/SA/Be/CaCO3 hydrogel beads. Unlike MB adsorption, the reusability of these hydrogel beads in phosphate adsorption reduced slightly after 5 cycles.

Preparation and characterization of silica nanoparticles as an efficient carrier for two bio‐detergents based enzymes

AbstractBio‐detergents are new bio‐friendly formulas that contain biobased ingredients, including enzymes. In the present study, alkaline protease and α‐amylase were immobilized via physisorption onto silica nanoparticles (SNPs). The derivatized SNPs served as major components of a prepared bio‐detergent. Alkaline protease was produced by the recombinant Bacillus subtilis cells that carry the protease genes on a multiple‐copy plasmid, while α‐amylase was commercially purchased. SNPs were prepared by the sol–gel method and well‐characterized through the Brunauer–Emmett–Teller (BET) method, scanning electron microscopy (SEM), transmission electron microscopy (TEM), zeta potential, X‐ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The adsorption capacity of the SNPs was determined via colorimetry through the adsorption of methylene blue dye (MB), with approximately 97% adsorption achieved under the conditions employed. The Langmuir isotherm well‐described the adsorption of MB on SNPs. High immobilization yield for the enzymes was obtained, and the storage stability of SNP‐alkaline protease and SNP‐α‐amylase was good, reaching 65% and 85% of their initial activities after 6 weeks of storage at 4°C, respectively. The immobilized enzymes could be reused for 7 cycles. Additionally, the immobilized enzymes retained residual activity to a greater extent than free enzymes in simulated basic detergent solutions. SNPs containing adsorbed alkaline protease and α‐amylase were mixed with a basic detergent solution, and the washing efficiency of some proteinous and starchy stains was examined through Hunter Lab spectrophotometry. The latter experiments demonstrated that the immobilized enzymes performed well during the washing process.

Removal of methylene blue dye from aqueous solution using an efficient chitosan-pectin bio-adsorbent: kinetics and isotherm studies.

Wastewater contains organic compounds, including dyes, which have potential risks to the environment. Hence, these compound needs to be eliminated from the aqueous solution. In the present study, chitosan-pectin composite (Cs-Pc) was used as an adsorbent to remove methylene blue dye (MB) from synthetic wastewater. To evaluate the parameters affecting adsorption, including the initial MB concentration, solution pH, contact time, and Cs-Pc dose, batch experiments were carried out. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR), and pH point of zero charges (pH pzc) were applied for characterizations of Cs-Pc. The optimum conditions were obtained with an initial MB concentration of 50mg L-1: solution pH ~ 11, Cs-Pc dose: 1.5g L-1 and 180min contact time, which caused 97.77% of MB removal. In addition, the removal efficiency of MB was more influenced by pH than by sorbate dose. Also, Cs-Pc had a higher ability to remove MB than chitosan and pectin, probably due to its highly porous structure and rough surfaces that provides active sites and facilitate MB adsorption. The maximum removal efficiency and the adsorption capacity of MB onto Cs-Pc at 500mg L-1 concentration under optimum conditions were 98.67% and 328.02mgg-1, respectively. The adsorption kinetics and isotherms were best described by pseudo-second-order and Freundlich equation, respectively. After four times of recycling, the removal efficiency of MB was above 96%. Electrostatic and pi-pi interactions are the main mechanisms for the removal of MB onto the adsorbent. So the application of Cs-Pc is promising for MB removal from polluted solutions not only due to its strong adsorbing capability but also due to its excellent ability to reuse.

Removal of anionic and cationic dyes using porous chitosan/carboxymethyl cellulose-PEG hydrogels: Optimization, adsorption kinetics, isotherm and thermodynamics studies

Chitosan (CS)/carboxymethyl cellulose (CMC) porous hydrogels chemically crosslinked by epichlorohydrin were synthesized using polyethylene glycol (PEG) as a pore-forming agent for anionic (Congo red, CR) and cationic (methylene blue, MB) dyes removal from aqueous solutions. The swelling ratio of hydrogels prepared with 2 % CS and 2 % CMC (CS2/CMC2) exhibited optimal performance at different pHs. The addition of PEG into hydrogels (denoted as CS2/CMC2-PEG1.25) exhibited a significantly higher adsorption for CR and MB, increasing from 117.83 to 159.12 mg/g and 110.2 to 136 mg/g, respectively. The comprehensive analyses of Fourier transform infrared spectroscopy, thermalgravimetric study and scanning electron microscopy showed that CS2/CMC2-PEG1.25 hydrogels became more porous with no significant changes in intermolecular and intramolecular interactions, compared with CS2/CMC2 hydrogels. The adsorption process for CR and MB conformed to the pseudo-second-order and pseudo-first-order kinetics models, respectively. The results of adsorption isotherm for CR followed both Freundlich and Langmuir models with the maximum adsorption capacities of 1053.88 mg/g, whereas the isotherm for MB fitted the Langmuir model better with the maximum adsorption capacities of 331.72 mg/g. The thermodynamic study results proved that the CR and MB adsorption by hydrogels was spontaneous, but the CR adsorption was endothermic and the MB adsorption was exothermic.

Fabrication of a hybrid phase TiO2/g-C3N4 heterojunction composite with enhanced adsorption and photocatalytic degradation of MB under visible light

Excellent MB adsorption and degradation capacity of hybrid phase TiO2/g-C3N4 photocatalysts based on surface polarization and S-scheme charge transfer.

Preparation and characterization of novel cellulose based adsorbent with ultra-high methylene blue adsorption performance

Although zeolitic imidazole framework-8 (ZIF-8) has been widely used as the organic dye adsorbent, a suitable carrier is needed to solve the issues of low stability and poor dispersibility in water. Poly(acrylic acid) was grafted onto cellulose to prepare MAA aerogel with more active sites for MB adsorption which was applied as the carrier for ZIF-8. Here, ZIF-8/MAA composite aerogel was prepared by in situ growing the ZIF-8 nanoparticles onto the walls of the pores of MAA aerogel. The prepared adsorbent was characterized by SEM, FTIR, and TG analysis. A series of adsorption experiments were carried out to optimize the various parameters affecting MB adsorption behaviors (the adsorbent dosage, solution pH, initial MB concentration, adsorption time, and adsorption temperature). The experimental data for the adsorption process followed a pseudo-secondary kinetic model, more in line with the Langmuir isotherm (R2 = 0.992), with a maximum adsorption capacity of 1492.99 mg/g. The prepared adsorbent exhibited great reusability even after five repeated cycles of adsorption-regeneration. The adsorption mechanism was discussed in depth. Thus, the prepared ZIF-8/MAA aerogel can be used as an environmentally friendly, efficient, stable and reusable adsorbent for MB in wastewater treatment.

Influence of extraction techniques on the adsorption capacity of methylene blue on sawdust: Optimization by full factorial design

Wood wastes have been widely studied for their adsorption properties in recent years. Researchers have mainly been interested in Atlas cedar sawdust. The present work studies four adsorbents after different extraction (hydrodistillation, soxhlet, maceration, and ultrasound) for methylene blue adsorption. The points discussed concern the operating conditions used during adsorption, thermodynamic, kinetic and other models describing the adsorbent-adsorbate system, and the effect of the main operating parameters (adsorbate concentration, treatment pH, and adsorbent concentration) was investigated using the full factorial design. The best adsorbent is the residue of sawdust generated after extraction via maceration: the yield of methylene blue adsorption is 98.42 % and the adsorbed quantity (Qads = 7.84 mg/g) is close to that of powdered activated carbon used for comparison (Qads = 9 mg/g). According to the kinetic result, the second order describes well the adsorption of MB onto the four types of Cedar Sawdust. The thermodynamic study confirms the physisorption process in which the enthalpy was found low to 40 kJ·mol−1.

Kinetic and thermodynamic studies of adsorption of lead (ii) ions on magnetite, baobab (Adansonia digitate) and magnetite - baobab composite

The detrimental consequences of excessive levels of heavy metal contamination on living things served as the motivation for this study. Adsorption of Pb(II) ions was investigated on synthetic magnetite (MG), baobab fruit shell (BB) and magnetite-baobab composite (MB). The batch equilibrium technique was used to investigate the adsorption of Pb(II) ions. The effects of initial metal concentrations (15-500 mg/L), adsorbent dose (0.05-0.3 g), contact time (5-150 min), pH (2-8) and temperature (303-343 K) on the adsorption capacity of the adsorbent were studied. Langmuir, Freundlich and Temkin isotherms were used to describe the adsorption of Pb(II) ions. The maximum adsorption capacity, qmax, of MB, MG and BB was 249.86, 227.45 and 34.67 mg/g respectively at a concentration of 500 mg/L of Pb(II) ions. Freundlich model was shown to have the best fit for the adsorption data in the following order: BB &gt; MG &gt; MB, with R2 values of 0.9954, 0.980 and 0.9797 respectively. Freundlich adsorption intensity for MG, BB and MB are 1.590, 1.339 and 1.761 respectively. The kinetic and thermodynamic investigations revealed that the adsorption followed pseudo-second-order kinetics and endothermic process. The amount of Pb(II) ions adsorbed after each stage of the desorption process varied between the different acid concentrations, according to sorption-desorption studies using spent adsorbents. The highest stepwise adsorptions of Pb(II) ions were observed when 0.5 M HCl was utilized as a stripping agent for BB while 0.1 M HCl favoured MG and MB.

Activated carbon from H3PO4 -activated Moringa Stenopetale Seed Husk for removal of methylene blue: Optimization using the response surface method (RSM)

In this study, an alternative precursor for production of activated carbon was introduced using Moringa Stenopetale Seed Husk (MSSH). Moreover, H 3 PO 4 was used as a chemical activator in the thermal carbonization process to convert MSSH into activated carbon. The prepared adsorbent was characterized using proximate analysis and Instrumental like FT-IR, SEM/EDX, and XRD. The optimization process was developed using the Box-Behnken methodology (BBM) and the response surface method (RSM). Analysis of variance (ANOVA) revealed a good agreement between experimental and predicted value. Investigation of the processing parameters was done using the batch adsorption method. The optimal conditions for removing methylene blue were found to be the initial dye concentration (316 mg/L), contact duration (19.3 min), adsorbent dosage (0.055 g), and shaking speed (176 rpm). Maximum efficacy was found to be 99.4%, and the highest adsorption capacity was 436.68 mg/g. The experimental results have been best fitted well by the Langmuir isotherm model with the higher correlation coefficients of R 2 = 0.954 rather than Freundlich and Temkin adsorption isotherm. This indicates that the process followed homogenous adsorption of adsorbate on the surface of adsorbent. The adsorption kinetics was best fitted with pseudo-second order kinetics. The result of thermodynamic parameters showed that a negative value of ΔG o and positive ΔH o confirms the spontaneous and endothermic nature of the adsorption of MB onto the adsorbents. The positive values of ΔS o indicate the increase in randomness of at the solid-liquid interface during the adsorption process. Generally, the results indicate that activated carbon prepared from MSSH can be used as a low cost, easily applicable and eco-friendly alternative adsorbent for treatment of effluents containing MB dye. • Activated Carbon was prepared form Moringa stenopetale seed husk. • The Activated carbon prepared was characterized by proximate value and analytical instruments. • The Response surface methodology (RSM) and Box-Behnken approach were used to create the optimization procedure. • Different Adsorption parameters and Adsorption models was Conducted. • The highest adsorption capacity was 436.68 mg/g, and maximum efficacy was found to be 99.4%