Batch Technique Research Articles

Deep Cleaning of Crystal Violet and Methylene Blue Dyes from Aqueous Solution by Dextran-Based Cryogel Adsorbents.

Polysaccharides have recently attracted growing attention as adsorbents for various pollutants, since they can be extracted from a variety of renewable sources at low cost. An interesting hydrophilic and biodegradable polysaccharide is dextran (Dx), which is well-known for its applications in the food industry and in medicine. To extend the application range of this biopolymer, in this study, we investigated the removal of crystal violet (CV) and methylene blue (MB) dyes from an aqueous solution by Dx-based cryogels using the batch technique. The cryogel adsorbents, consisting of cross-linked Dx embedding a polyphenolic (PF) extract of spruce bark, were prepared by the freeze-thawing approach. It was shown that the incorporation of PF into the Dx-based matrix induced a decrease in porosity, pore sizes and swelling ratio values. Moreover, the average pore sizes of the DxPF cryogels loaded with dyes further decreased from 42.30 ± 7.96 μm to 23.68 ± 2.69 μm, indicating a strong interaction between the functional groups of the cryogel matrix and those of the dye molecules. The sorption performances of the DxPF adsorbents were evaluated in comparison to those of the Dx cryogels and of the PF extract. The experimental sorption capacities of the DxPF cryogel adsorbents were higher in comparison to those of the Dx cryogels and the PF extract. The DxPF cryogels, particularly those with the highest PF contents (sample DxPF2), demonstrated sorption capacities of 1.2779 ± 0.0703 mmol·g-1, for CV, and 0.3238 ± 0.0121 mmol·g-1, for MB. The sorption mechanisms were analyzed using mathematical models, including Langmuir, Freundlich, Sips and Dubinin-Radushkevich isotherms, and kinetic models, like pseudo-first-order (PFO), pseudo-second-order (PSO), Elovich and intra-particle diffusion (IPD). The sorption process was best described by the Sips isotherm and PSO kinetic models, indicating chemisorption as the dominant mechanism. This study outlines the importance of developing advanced renewable materials for environmental applications.

Optimized Electrocatalytic Adsorption Degradation of Oilfield Produced Water Using New Dimension Stable Anode

AbstractIn this study, we synthesized a novel electrode for electrocatalytic adsorption by fabricating ACF‐TiO2 via the sol‐gel method and binding it with IrO2‐TaO2. The electrode's effectiveness in treating oilfield produced water (OPW) was evaluated using batch techniques. Comprehensive characterization, including scanning electron microscopy (SEM), energy‐dispersive spectrometry (EDS), Brunauer‐Emmett‐Teller (BET) analysis, and Fourier‐transform infrared (FTIR) spectroscopy, confirmed uniform TiO2 loading onto the ACF surface, preserving structural integrity. BET analysis indicated increased mesopore volume and enhanced organic adsorption capacity without compromising microporous structure. Additionally, FTIR analysis revealed the emergence of functional groups conducive to adsorption and catalytic reactions. Freundlich isotherms and pseudo‐first‐order kinetics best fit the adsorption data. Remarkably, even after five cycles, the electrode maintained high removal efficiencies for chemical oxygen demand (COD) and oil content at 91.35 % and 91.12 %, respectively. We further investigated the complex phenomena of material adsorption, electrochemical oxidation, and desorption during electrocatalytic adsorption, highlighting the importance of solid‐phase adsorption and liquid‐phase electrocatalytic oxidative decomposition in OPW treatment. Comparison with similar electrodes and DSA electrodes demonstrated the superior performance and practicality of the IrO2‐TaO2‐ACF(TiO2) electrode. Its cost‐effectiveness and regeneration method further enhance its applicability in real‐world scenarios, emphasizing its potential in water treatment.

In Situ Eutectic Formation in a Polymeric Matrix via Hot-Melt Reactive Extrusion and the Use of Partial Least Squares Regression Modeling for Reaction Yield Determination.

There has been a significant volume of work investigating the design and synthesis of new crystalline multicomponent systems via examining complementary functional groups that can reliably interact through the formation of noncovalent bonds, such as hydrogen bonds (H-bonds). Crystalline multicomponent molecular adducts formed using this approach, such as cocrystals, salts, and eutectics, have emerged as drug product intermediates that can lead to effective drug property modifications. Recent advancement in the production for these multicomponent molecular adducts has moved from batch techniques that rely upon intensive solvent use to those that are solvent-free, continuous, and industry-ready, such as reactive extrusion. In this study, a novel eutectic system was found when processing albendazole and maleic acid at a 1:2 molar ratio and successfully prepared using mechanochemical methods including liquid-assisted grinding and hot-melt reactive extrusion. The produced eutectic was characterized to exhibit a 100 °C reduction in melting temperature and enhanced dissolution performance (>12-fold increase at 2 h point), when compared to the native drug compound. To remove handling of the eutectic as a formulation intermediate, an end-to-end continuous-manufacturing-ready process enables feeding of the raw parent reagents in their respective natural forms along with a chosen polymeric excipient, Eudragit EPO. The formation of the eutectic was confirmed to have taken place in situ in the presence of the polymer, with the reaction yield determined using a multivariate calibration model constructed by combining spectroscopic analysis with partial least-squares regression modeling. The ternary extrudates exhibited a dissolution profile similar to that of the 1:2 prepared eutectic, suggesting a physical distribution (or suspension) of the in situ synthesized eutectic contents within the polymeric matrix.

Innovative pyrazole–phosphoramidate derivative for effective mercury adsorption and their application for Egyptian industrial waste samples

ABSTRACT Mercury, known for its severe health and environmental impacts even in trace amounts, necessitates effective removal from water systems. This research focuses on preparation of a novel adsorbent of 3,9−bis((4−amino−5−hydroxy−1 H−pyrazol−3−yl)amino)−2,4,8,10−tetraoxa−3,9−diphosphaspiro[5.5] undecane 3, 9−dioxide (PADP) for Hg(II) ions adsorption. To validate functionalization steps and elucidate PADP’s physical and chemical properties, a comprehensive array of assays, including FTIR, surface area, BET, TGA, 13CNMR, Mass spectra, 31PNMR and1HNMR were employed. The study systematically examined several factors controlling mercury sorption, including temperature, adsorbent dosage, pH, interaction time, and mercury concentration using the batch technique. Optimal sorption effectiveness was achieved at pH 5, with an interaction time of 50 min, an 80 mg adsorbent dose, at ambient temperature. The newly devised adsorbent exhibited an impressive adsorption capacity (qe) of 357 mg of Hg(II) per Litre, with empirical data fitting the Langmuir and Dubinin−Radushkevich adsorption isotherm models. The kinetics of mercury sorption followed second-order and Elovich kinetics models. Thermodynamic aspects, including ΔGº, ΔSº, and ΔHº, were also investigated, providing appreciated perceptions into the energetic dynamics of the sorption process. Thermodynamics has shown that the sorption of mercury ions is both endothermic and spontaneous. Additionally, mercury adsorption in the occurrence of other ions was explored, highlighting the selectivity of the modified Pyrazole – Phosphoramidate adsorbent for mercury removal. PADP demonstrates superior performance in removing Hg(II) from wastewater effluents, outshining a range of both natural and synthetic adsorbents previously used for this purpose. This superiority is evident when comparing its adsorption capacity (qo) against those of other adsorbents, showcasing its exceptional efficacy in purifying water from mercury contamination.

Chemical Oxidation for Oil Separation from Oilfield-Produced Water / Homogeneous Process by Batch Technique

Chemical Oxidation for Oil Separation from Oilfield-Produced Water / Homogeneous Process by Batch Technique

Comparing the potential of benchtop and handheld mid-infrared spectrometers for predicting soil phosphorus (P) sorption capacity and evaluating the influence of sample preparation

Traditional soil phosphorus (P) sorption capacity is examined from a Langmuir isotherm batch technique, which is time-consuming, labour intensive and generates chemical waste. In this work, we provide an efficient and convenient technique with MIR spectroscopy to predict the Langmuir parameter of soil P sorption maximum capacity (Smax, mg·kg−1).Four spectral libraries from benchtop (Bruker) and handheld (Agilent) MIR spectrometers were built with samples in two particle size ranges, <0.100 mm (ball-milled) and <2 mm. respectively. Using an archive of samples with a database of sorption parameters, soils were classified into ‘low’ and ‘high’ sorption capacities. Chemometric regression models of partial least squares (PLS), Cubist, support vector machine (SVM) regression and random forest (RF) were evaluated for Smax prediction. Bruker spectral libraries with both soil particle sizes yielded ‘excellent models’, with SVM predicting Smax values with high accuracy (RPIQV = 4.50 and 4.25 for the spectral libraries of the ball-milled and <2 mm samples, respectively). In comparison, the Agilent handheld spectral libraries contained more noise and less resolution. For Agilent MIR spectroscopy, more homogeneous samples after ball milling resulted in a higher accurate Smax prediction. For Agilent libraries of ball-milled samples, an ‘approximate quantitative model’ (RPIQV = 2.74) was obtained from the raw spectra using the Cubist algorithm. However, for Agilent spectroscopy of <2 mm samples, the best performing Cubist algorithm can only achieve a ‘fair model’ (RPIQV=2.23) with the potential to discriminate between ‘low’ and ‘high’ Smax values.The results suggest that the benchtop spectrometer can predict the Langmuir Smax value with high accuracy without the need to ball mill samples. However, the handheld spectrometer can only make approximate quantitative predictions of Smax for ball-milled samples. For <2 mm samples, Agilent can only be used to classify ‘low’ and ‘high’ sorption capacity soils.

Fabrication of an innovative phosphonate Schiff base adsorbent for molybdenum adsorption and its applications for molybdenum adsorption from spent hydrodesulfurization catalyst

AbstractBACKGROUNDTo investigate the recovery of molybdate from water and hydrodesulfurization catalysts, a novel synthesized phosphonate Schiff base, 4,4′‐(((2,2‐dimethylpropane‐1,3‐diyl) bis(azaneylylidene)) bis(methaneylylidene)) bis(2‐methoxyphenol) (HMI) and 4‐(((3‐((4‐(((S)‐hydroxyhydrophosphoryl)oxy)‐3‐methoxybenzylidene) amino)‐2,2‐dimethylpropyl)imino)methyl)‐2‐methoxyphenyl hydrogen phosphonate (HIMP), was utilized. This study aimed to assess the structural and property aspects of this synthesized compound using diverse characterizations, including FTIR, Thermogravimetric Analysis (TGA), mass spectrometry (GC–MS), fluorescence transfer spectra, scanning electron microscopy (SEM), and 1H‐NMR, 13C‐NMR, and 31P‐NMR.RESULTSThe study systematically examined several factors controlling molybdate recovery, including temperature, adsorbent dosage, pH, interaction time, and molybdate concentration using the batch technique. Optimal sorption effectiveness was achieved at pH 2, with an interaction time of 40 min, a 0.06 g adsorbent dose, at ambient temperature. The newly devised adsorbent exhibited an impressive adsorption capacity (Qe) of 372.54 mg of Mo per gram, with empirical data fitting the Langmuir and D‐R adsorption models. The kinetics of molybdate uptake followed second‐order kinetics. Thermodynamic aspects, including ΔG°, ΔS°, and ΔH°, were also investigated, providing appreciated perceptions into the energetic dynamics of the sorption process. Additionally, molybdate adsorption in the occurrence of other ions was explored, highlighting the selectivity of the modified phosphonate Schiff base for molybdate removal.CONCLUSIONThe study underscores the potential of the modified phosphonate Schiff base as a crucial adsorbent for molybdate elimination from both solutions and spent hydrodesulfurization catalysts. The findings offer important insights into the adsorption kinetics, thermodynamics, and selectivity of the adsorbent, enhancing our understanding of molybdate recovery processes and their broader applications. © 2024 Society of Chemical Industry (SCI).

Cellulose-citric acid-chitosan@metal sulfide nanocomposites: Methyl orange dye removal and antibacterial activity

In this study, to develop efficient adsorbents in removing water pollution, new cellulose-citric acid-chitosan@metal sulfide nanocomposites (CL-CA-CS@NiS and CL-CA-CS@CuS) were synthesized by one-pot reaction at mild conditions and characterized using X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM), Energy Dispersive X-ray (EDX) and Brunauer-Emmett-Teller (BET) isotherm. The results of characterization techniques confirm that the desired compounds have been successfully synthesized. The as-prepared composites were applied for the removal of methyl orange (MO) dye from aqueous solutions using a batch technique, and the effect of key factors such as initial pH, shaking time, MO concentration, temperature and adsorbent dose were investigated and discussed. Adsorption results exhibited positive impact of temperature, shaking time and adsorbent dose on the MO removal percent. The MO removal percent has been increased over a wide range of pH from 2 (27.6 %) to 6 (98.8 %). Also, almost being constant over a wide range of MO concentration (10–70 mg/L). The results demonstrated that the maximum removal percentage of MO dye (98.9 % and 93.4 % using CL-CA-CS@NiS and CL-CA-CS@CuS, respectively) was achieved under the conditions of pH 6, shaking time of 120 min, adsorbent dose of 0.02 g, MO concentration of 70 mg/L and temperature of 35 °C. The pseudo-second-order (PSO) and Langmuir models demonstrated the best fit to the kinetic and equilibrium data. Also, the thermodynamic results showed that the MO removal process is endothermic and spontaneous in nature. The MO adsorption can be happened by different electrostatic attraction, n-π and π-π stacking and also hydrogen bonding interaction. In addition, antibacterial activity of CL-CA-CS@NiS and CL-CA-CS@CuS nanocomposites exhibited a superior efficiency against S. aureus.

U(VI) sorption on illite in the Co-existence of carbonates and humic substances

The presence of carbonates or humic substances (HS) will significantly affect the species and chemical behavior of U(VI) in solution, but lacking systematic exploration of the coupling effect of carbonates and HS under near real environmental conditions at present. Herein, the sorption behavior of U(VI) on illite was systematically studied in the co-existence of carbonates and HS including both humic acid (HA) and fulvic acid (FA) by batch technique. The distribution coefficients (Kd) increased as function of time and temperature but decreased with increasing concentrations of initial U(VI), Ca2+, and Mg2+, as well as ion strength. At pH 2.0–10.5, the Kd values first increased rapidly and then decreased visibly, with its maximum value appearing at pH 5.0, owning to the changes in the interaction between illite and the dominant species of U(VI) from electrostatic attraction to electrostatic repulsion. The sorption was a heterogeneous, spontaneous, and endothermic chemical process, which could be well described by pseudo-second-order kinetic and Flory-Huggins isotherm models. When carbonates and HA/FA coexisted, the Kd values always increased first and then decreased as a function of pH, with the only difference for HA and FA being the key pH (pHkey) at which the promoting and inhibiting effects on the sorption of U(VI) onto illite undergo a transition. The carbonates and HS have a synergistic inhibitory effect on the U(VI) sorption onto illite at pH 7.8. FTIR and XPS spectra demonstrated that the hydroxyl groups on the illite surface and in the HS were involved in U(VI) sorption on illite in the presence of carbonates. These results provide valuable data for a deeper understanding of U(VI) migration in geological media.

Montmorillonite Clay as an Adsorbent for the Remediation of Cd (II) Ions in Aqueous Solutions: A Comparison With Pb (II) Ions

ABSTRACTHeavy metal ions are hazardous to both human health and the environment. Montmorillonite (MMT) clay has recently piqued interest for its adsorption capacity of heavy metals and its use in controlling contaminants, in particular in surface and waste waters. This research sheds light on the possibility of the application of natural Albanian MMT clay from the Prrenjas Region of Albania as an adsorbent of Cd (II) ions in aqueous solutions, making a comparison with the capacity of such clay for the adsorption of Pb (II) ions. The set of variables studied included concentrations of metal ions, amount of clay pH, time, and temperature of interaction and adsorption process (all of them following batch technique), and optimal conditions have been determined. The adsorption capacity of natural clay for Cd (II) ions was 6.735 mg/g, as compared to 17.9 mg/g for Pb (II) ions. Langmuir and Freundlich isotherms were applied to evaluate the mode of adsorption with results showing that all isotherms are linear and the Langmuir model fitted better with the experimental data. It is determined that the adsorption of Cd (II), similar to that of Pb (II), is well‐fitted by the second‐order reaction kinetic following the Lagergen model. The results demonstrate good potentiality for Prrenjas MMT as a low‐cost adsorbent to remove Cd (II) from aqueous systems, in particular, for wastewater treatment.

Effect of soil properties on phosphate desorption from some cultivated soils in arid region

&lt;p&gt;&lt;span lang="EN-US"&gt;Kinetics of soil chemical processes is one of the most important areas in environmental chemistry for metals availability in soils and mechanisms of desorption. Phosphorus (P) is one of the most important macronutrients that control plant growth and crop production. The present study aims to evaluate the influences of soil properties of Alluvial (&lt;em&gt;Typic torrerets&lt;/em&gt;) and calcareous (&lt;em&gt;Typic calcids&lt;/em&gt;) on the Kinetics of P desorption using batch and anion exchange resin techniques used for P adsorption, which is highly correlated with P uptake by growing plants. Results indicated that P desorption was best described by empirical modified Freundlich (power function) and Elovich equations and, to a lesser degree, by theoretical diffusion and first-order equations. The rate of P desorption from the alluvial soils was positively and highly correlated and largely controlled by clay content (r=0.96&lt;sup&gt;**&lt;/sup&gt;) and surface area (r=0.87&lt;sup&gt;**&lt;/sup&gt;), as indicated by the simple correlation coefficient and R&lt;sup&gt;2 &lt;/sup&gt;in the multiple stepwise regression analysis. These soil properties largely controlled the variations in the kinetic parameters that describe the rate of P desorption and P intensity in the four tested kinetic models. On the other hand, calcium phosphate and active CaCO&lt;sub&gt;3&lt;/sub&gt; contents in the calcareous soils were negatively correlated. They largely controlled the variations in the rate and intensity parameters of the kinetic models. These results suggest that surface precipitation on the CaCO&lt;sub&gt;3&lt;/sub&gt; surface controls P desorption in calcareous soils, while reversibly, phosphate adsorption on the clay surface controls P desorption in the alluvial soils, which decreases in both cases, crop production.&lt;/span&gt;&lt;/p&gt;

Utilization of macroporous beads impregnated with Cyanex 572 for effective separation of Sr(II), Y(III), and Zr(IV) from chloride medium: batch and fixed-bed column study

This work focuses on using a new, inexpensive adsorbent, Amberlite XAD–4 resin impregnated with Cyanex 572 to extract and separate Zr(IV) from its parents Y(III) and Sr(II). The extraction performance was investigated using both batch and continuous flow techniques. The highest separation factor of Zr from Y and Sr was obtained at 0.05 mol L−1 HCl. Zr(IV), Y(III), and Sr(II) were found to have maximal monolayer capacities of 29.1, 9.3, and 6.1 mg g−1, respectively. Chromatography was utilized to effectively separate the relevant metals from their mixed solution in a single step, yielding high recovery values of approximately 99.0%.

Impact of the In Vitro Human Digestive Environment on the Interaction Between Vitamin C and Microplastics

Microplastics are present in the environment and living systems and bind with contaminants, proteins, and lipids. However, the interaction of vitamins with microplastics under in vitro conditions is unknown. Therefore, the aim of this study was to evaluate the interaction of vitamin C with microplastics obtained from food packages for simulated intestinal and gastric fluids. Sorption responses (kinetic and isotherm models) were examined using a batch technique with high-performance liquid chromatography-mass spectrometry (HPLC-MS). The results show that the sorption was achieved in 180 and 45 min for gastric and intestinal conditions. Vitamin C was adsorbed between 3 and 20% onto microplastics under in vitro digestive conditions. The sorption of vitamin C on microplastics conformed to the pseudo-second order (PSO) kinetic model. The isotherm models showed that sorption fitted the Temkin and Freundlich models.

Improvement of the photo-Fenton performance at near neutral pH by the addition of tannic acid from tea leaves waste as a complexing agent in the Pb(II) photo-oxidation

&lt;p&gt;IIntroducing tannic acid from tea leaves waste as a complexing agent of Fe(III) into photo-Fenton process to prevent Fe(OH)3 precipitation at pH 7, and further to increase photo-Fenton activity in the near neutral pH for Pb(II) photo-oxidation is systematically addressed. The photo-Fenton process for Pb(II) photo-oxidation involving Fe2+ and H2O2 solutions as well as UV light was conducted by batch technique, both in the absence and present of tannic acid. Furthermore, the optimization of tannic acid concentration, solution pH, and reaction time were also conducted. The research results assign that the addition of tannic acid in the photo-Fenton process for photo-oxidation of Pb(II) is able to considerably enhance the effectiveness at pH 6-8 (near neutral pH). The activity of the tannic acid from tea leaves waste is comparable to the that of the commercial tannic acid. The best condition of Pb(II) photo-oxidation having 10 mg.L-1 in 50 mL of the solution can be reached by using Fe2+ as high 10 mmol.L-1, H2O2 100 mmol.L-1, with the addition of tannic acid as much as 30 mg.L-1 at pH 7 and 60 min of the time that gave about 85% of the photo-oxidation effectiveness. It is also indicated that the Pb(II) photo-oxidation has resulted in the harmless PbO2 solid . Hence, it is obviously assigned that the priceless tea waste could significantly contribute in the improvement of the photo-Fenton performance to prevent environmental pollution.&lt;/p&gt;

Conversion of iron rusty waste into Fe dopant of TiO2 to increase its photocatalytic activity under visible light for photodegradation of rhodamine-B

This present research deals with a systematic study on doping TiO2 with Fe from iron rusty waste to improve the activity under visible light irradiation through gap narrowing in the TiO2 semiconductor structure. The doping was conducted by the sol-gel method by interacting titania tetra isopropoxide (TTIP) with Fe3+ ions dissolved from the iron rusty waste in aqua regia. The concentration of the Fe3+ was varied giving mole ratio to TiO2 as (1:0.04), (1:0.08), (1:0.12), (1:0.16), and (1:0.20). The activity of TiO2–Fe was examined for Rhodamine-B dye photodegradation through batch technique. The influences of the Fe fraction, irradiation time, photocatalyst weight, and solution pH were also evaluated to find the best condition for the dye degradation. The research results attribute that doping TiO2 with Fe3+ from the rusty waste has successfully shifted the band gap energy into the visible regime, which remarkably increases the TiO2 activity under visible light irradiation. The increase is controlled by the Fe fraction in the photocatalyst, and the best performance is shown by TiO2–Fe with a 1:0.12 mol ratio. From the dye photodegradation, it is found that the highest degradation effectiveness (99.20 %) of 5 mg/L Rhodamine B in 50 mL of the solution, can be obtained by using 50 mg of TiO2–Fe (1:0.12), pH 5, in 90 min. The photocatalyst can be reused twice in the photodegradation process without a significant decrease in photoactivity. It is implied that the rusty waste has potential as a Fe dopant source creating a better visible responsive photocatalyst.

Treatment of Produced Water from Niger Delta Oil Fields Using Selected Bio-Adsorbents

Produced water (PW) is the vast amount of water produced from subsurface during the extraction of oil and gas. PW contains heavy metals which are detrimental to the environment. The majority of PW treatment technologies, which have been in use for many years, have reportedly failed to bring some impurity and metal concentrations down to permissible disposal levels. This study was done to determine how well three locally available materials which are eggshells, groundnut shells, and sugarcane bagasse used in the treatment of PW obtained from Niger Delta oil fields. The adsorbents were ground, and sieved into sizes of 425 and 1180 microns. They were treated individually with diluted nitric acid (400mL of 0.4mol/ LHNO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;) for 24 hours to remove pigments. They were filtered, dried, and rinsed with distilled water until the pH became neutral. PW samples were analysed for heavy metals using an Atomic Absorption Spectrophotometer (AAS). The PW samples were treated with the bio-adsorbents in a batch technique. The metals analysed were As, Cu, Pb and Fe. The bioadsorbents were able to reduce the concentration of the metals to 87%, 91%, 100% and 88% respectively. Langmuir and Freundlich isotherm models were used to analyse the adsorption system. It was observed that the finer the adsorbents the better the adsorption result. 425 microns was able to produce a better result compared with 1180 microns.

Physicochemical interaction of microstructured drumsticks with synthetic Dye: The tailoring of surface phenomenon

The current study shows that drumstick powder is a potential adsorbent to remove Congo Red from synthetic wastewater by a batch technique. CR as a textile waste harms the ecology and the water ecosystem, and it should be removed from WW. At various experimental conditions, various operating parameters such as initial concentration of dye (25–300 ppm), contact time (10–240 mins), pH (1–12) and adsorbent dosage (0.1–1.0 g/L) were investigated. The reaction kinetics and adsorption isotherms were examined. Maximum removal of dye has been found at pH 2. Dye concentration is an important factor and it is inversely related to the percentage removal. 100 ppm was chosen as the IC for the optimization experiment. Increasing the amount of adsorbent dosage and contact time, there is an rise in the percentage removal of dye particles. The optimum adsorbent dosage was found 0.5 g/L and the contact time 90 mins. The maximum adsorption capacity has been found to be 114.94 mg/g. The adsorption mechanism closely matched the Freundlich isotherm and pseudo-second-order kinetic models.

Experimental and theoretical study for the sorption of Ni2+ and Cd2+ onto phosphoryl functionalized aluminum silicate composite

Phosphoryl functionalized Aluminum silicate (ASP) composite sorbent was synthesized using sol–gel technique and characterized with different techniques. The synthesized sorbent was tested for the sorption of Ni2+ and Cd2+ in aqueous solution at both single- and binary-solute systems under simulated conditions using batch technique. Batch experiments were executed as a function of pH, initial metal ion concentration and temperature. Structural and surface morphology of the synthesized sorbent were determined using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). The studied kinetic models suggested that the sorption of Ni2+ and Cd2+ onto ASP was found to follow the pseudo-second order and the Langmuir-Freundlich model was the best model to depict the sorption isotherms. The sorption equilibria of both ions were analyzed using two diverse statistical physics models (homogeneous and heterogeneous monolayer models). A Theoretical scrutiny of statistical physics calculations indicated that Ni2+ and Cd2+ sorption was multi-ionic where two sorption sites were involved but with a diverse contribution degree. The removal nature of Ni2+ and Cd2+ was endothermic and the calculated sorption amounts at saturation implied that Ni2+> Cd2+. Calculated interaction energies indicated the participation of physical forces in the sorption of both ions onto the synthesized sorbent surface and the variation of these sorption energies confirmed that both sorption sites participated in the removal of Ni2+ and Cd2+ but through different interactions type. Ions sorption capacity was increased with the temperature owing to increase in thermal agitation. This study reveals that phosphoryl functionalized aluminum silicate is an efficient sorbent that can be used for the sorption of Ni2+ and Cd2+ from aqueous solutions in both single- and binary -solute systems.

Synthesis and characterization of alginate-polyacrylic acid/multiwalled carbon nanotubes composite with efficient removal for nigrosine dye

ABSTRACT The current study detailed the efficacy of a simply prepared alginate-polyacrylic acid/functionalized multiwalled carbon nanotubes (Alg-PAA/f-MWCNTs) composite for adsorption of nigrosine dye (acid black II) from aqueous environments. Firstly, preparation of the Alg-PAA/f-MWCNTs composite was achieved via gamma radiation-induced template polymerization of AA onto the Alg/f-MWCNTs surface. The maximum grafting efficiency (GE%) of AA onto the surface of Alg/f-MWCNTs was ~ 82% under the optimized conditions: (2.5 wt% Alg, 30 wt% AA, 0.5 wt% f-MWCNTs, 0.6 wt% N,N’-methylenebisacrylamide (NMBA), and irradiation dose ~ 20 kGy). The structural characteristics, thermal features as well as the morphological appearance of the Alg-PAA/f-MWCNTs composite were validated using different analyses including FTIR, TGA, DTA, XRD and SEM. Additionally, the composite exhibited uniform particle size distribution (~150.7 nm), point of zero charge at pH = 6.28, and negative Zeta potentials of a minimum at pH = 2. The adsorption batch experiments showed good adsorption capacity for the nigrosine dye from their aqueous media with adsorption efficiency up to 83% using the batch technique at pH = 2.0 for 420 min. The adsorption of nigrosine dye onto Alg-PAA/f-MWCNTs is favorable thermodynamically, obeying the Freundlich isotherm model and controlled by a chemisorption mechanism. Additionally, the composite showed a good regeneration ability up to five times with almost the same removal of ~80%. The results demonstrated that the Alg-PAA/f-MWCNTs composite could be a promising candidate for the removal of nigrosine dye from industrial aqueous environments.

Mechanism insight of sorption of Er(III) and Nd(III) ions onto Aluminium barium tungstate synthesized via streamlined sol–gel technique: Time-transient study

Aluminium barium tungstate powder (ABT) was chemically synthesized via streamlined sol–gel technique and exploited as a sorbent material for sorption of erbium and neodymium ions from aqueous solutions under simulated conditions using batch technique. The pH influence, time and temperature factors have been studied. The sorption of neodymium ions was found to be marginally higher than that of erbium ions and the apparent sorption capacity has a progressive influence with temperature. Thermodynamic parameters such as Gibbs free energy change (ΔG◦), enthalpy change (ΔH◦) and entropy change (ΔS◦) were calculated. The negative ΔG◦ values declines with an increase in temperature value, demonstrating that the sorption reaction for both studied ions was spontaneous and more promising at greater temperature. The positive ΔH◦ values affirm that the nature of the sorption processes is endothermic. The comparison of different time transient models applied to the sorption data was assessed for the pseudo first-order (PFO), the pseudo second-order, (PSO) and homogeneous particle diffusion (HPD) models. The results revealed that both PSO and HPD models were found to best correlate the experimental sorption rate data and a monolayer model was adopted as the best suitable model to explore the sorption mechanism for both studied ions. The attained particle diffusion coefficients and rate constant values were acquired from the graphical illustration of the anticipated models. Activation energy change (Ea) and activation entropy change (ΔS±) were also calculated from the linearized Arrhenius model and indicated that the binding process between the sorbent and the studied ions occurred through chemisorption and the sorption of both ions onto synthetic sorbent took place through associative mechanism.