Maximum Sorption Capacity Research Articles

Competitive sorption behavior of mono, di, and trivalent ions in highly acidic waste by polymeric resin based on crotonic acid prepared by gamma radiation

Understanding the chemical behavior and interactions of mono, di, and trivalent metal ions in highly acidic solutions is very important in trying to predict their sorption process onto polymeric materials. In this work, the efficient polymeric resin has been prepared by gamma radiation approach during copolymerization synthesis of poly sodium styrene sulphonate and crotonic acid through systematic investigation. An installment of different parameters was constructed including polymer concentration, radiation dose, and how it affects equilibrium water content (EWC- swelling degree). The prepared polymer was characterized using Fourier Transform Infrared (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Dynamic Light Scattering (DLS), and point of zero charges (pHZPC) analyses. The structure of such prepared co-polymeric resin analogous reaction was constructed. It was discovered that when the quantity of poly sodium styrene sulphonate increases, the copolymer forms more quickly and produces white crystalline materials. The sorption behavior of Fe3+, La3+ Ce3+, Eu3+, Sr2+ and Cs+ ions on the polymeric material was tested in a highly acidic aqueous solution taking into consideration the optimum solution pH, and initial metal concentration. The sorption ratio between different valence is challenging because of the competition of ion-specific, and binding saturation effects. Fortunately, in highly acidic waste, the synthesized polymeric resin exhibit higher removal efficiency for trivalent metal ions including Fe3+, Eu3+,Ce3+, and La3+ more than divalent Sr2+ and monovalent Cs+ ions with maximum sorption capacity 58, 56, 52, 48, 38 and 6.4 mg/g respectively. Finally, the synthesized polymeric resin P(SSS-Co-CA) is considered a promising sorbent for the selective separation of trivalent metal ions, especially in highly acidic solutions produced from acid digestion of real samples containing trivalent lanthanides.

Biocatalyst Based on Magnetic Nanoparticles with Cu(II), Mn(II), Zn(II) and Immobilised Catalase

AbstractThis article described a process for the preparation of a Fe3O4 nanocatalyst modified with Mn(II), Cu(II) and Zn(II) ions immobilised with catalase. The effectiveness of the description of the ion sorption process was compared with four equilibrium models: Langmuir, Freundlich, Redlich–Peterson and Sips. The proposed models allow the description of both single- and multi-component sorption. The results were also verified by DFT analysis. The Langmuir model describing single-component sorption and the extended Langmuir model for multi-component systems with the best fit represented the sorption of metal ions on Fe3O4. The maximum sorption capacity values in the pseudo-second-order kinetic model were 10.76, 12.87 and 10.52 mg/g for Cu(II), Zn(II) and Mn(II) in the single-component systems and 11.79, 8.54 and 2.03 mg/g for Cu(II), Zn(II) and Mn(II) in the multi-component system, respectively. The kinetics parameters were described most accurately by a pseudo-second-order model, which suggested, along with the Extended Langmuir model, the chemical nature of the sorption. After preparation of the Fe3O4/Mn–Zn–Cu material, catalase was immobilised on the surface of the material. The final material was able to decompose hydrogen peroxide with an activity of 7130 units/g of material. Modification of the material with Mn(II), Cu(II) and Zn(II) resulted in an increase in H2O2 removal efficiency exceeding 99.9%.

Sorption Capacity of Polydimethylsiloxane Foams Filled with Thermal-Treated Bentonite-Polydimethylsiloxane Composite Foams for Oil Spill Remediation.

The spillage of oil causes severe and long-lasting impacts on both the environment and human life. It is crucial to carefully reconsider the methods and techniques currently employed to recover spilled oil in order to prevent any possible secondary pollution and save time. Therefore, the techniques used to recover spilled oil should be readily available, highly responsive, cost-effective, environmentally safe, and, last but not least, they should have a high sorption capacity. The use of sorbents obtained from natural materials is considered a suitable approach for dealing with oil spills because of their exceptional physical characteristics that support sustainable environmental protection strategies. This article presents a novel sorbent material, which is a composite siloxane foam filled with bentonite clay, aimed at enhancing the hydrophobic and oleophilic behavior of the material. The thermal treatment of bentonite optimizes its sorption capacity by eliminating water, and increasing the surface area, and, consequently, its interaction with oils. In particular, the maximum sorption capacity is observed in kerosene and naphtha for the bentonite clay thermally treated at 600 °C, showing an uptake at saturation of 496.8% and 520.1%, respectively. Additionally, the reusability of the composite foam is evaluated by squeezing it after reaching its saturation point to determine its sorption capacity and reusability.

A Cellulose Aerogel Made from Paper and Hemp Waste Added with Starch for the Sorption of Oil

One sustainable method of removing oil spills is the use of sorbents. In this study, aerogels made from paper waste and crosslinking starch are investigated as sorbents. Aerogels have a high porosity and, thus, achieve a high sorption capacity. The paper waste aerogels are compared with aerogel samples that also contain hemp fibres as a composite. After hydrophobisation with methyltrimethoxysilane, the maximum sorption capacity of crude oil, marine diesel oil and lubricating oil is investigated. Aerogels made of cellulose from paper waste with starch show the highest sorption capacity of about 50 gg−1 for all studied oils. Unfortunately, hemp fibres offer no advantage in sorption capacity, but they do mitigate a decrease in sorption capacity with an increase in cellulose fibre content. This could be an advantage in a possible commercial product, so that the properties do not vary as much.

Removal of Malachite Green Dye from Aqueous Solution Using Lemon Leaf Powder as an Adsorbent

The majority of developing nations experience significant water contamination from textile sector wastewater. The use of low-cost, environmentally friendly adsorbents has been researched as a means of addressing problems of water contamination and high costs for waste - water treatment processes. Malachite green is an incredibly dangerous colour that not only damages mammalian cells but also has a key influence in the growth of liver cancers. The life cycle of aquatic creatures, plants, and people is hampered by dye released into bodies of water without sufficient treatment. In this study, the powdered lemon leaves are utilized for removal of the aniline green dye. By using batch-style setting and design of the experiment (the Box– Behnken technique) adsorbent has been investigated & have been developed to evaluate the process's critical factors, including agitation time, size of adsorbent, dosage of adsorbent, pH, initial concentration and temperature. The acquired values were fitted with adsorption isotherms. Malachite green dye sequestration onto Lemon Leaf Powder was chosen using kinetic models. The results of the trials showed that employing powdered lemon leaves, malachite green could be removed to a maximum of 82.21%. Malachite green dye concentration of 50 mg/L, temp of solution 303 K, and dosage of adsorbent 20 g/L are the ideal parameters. Lemon leaf powders have a maximum sorption capacity (qmax) of 8.08 mg/g. The equilibrium was more accurately modelled using the Freundlich isotherm. When compared to other models, the data which fits the pseudo 2nd order kinetics model is better. Previously researchers had proved several low– cost materials such as wheat bran, marina alga, wood apple shell etc In the current work, to remove malachite green dyes the efficacy of citrus lemon leaves is thoroughly done. The operating parameters that are optimized include dye solution concentration, initial solution pH, sorbent dose, and temperature. Studies on thermodynamics have demonstrated that the adsorption process was endothermic & spontaneous.

Aminophosphonate CuO nanocomposites for uranium(VI) removal: Sorption performance and mechanistic study

Two aminophosphonate matrices (mono-aminophopshonate, MAP, and bi-aminophosphonate, BAP) are synthesized, varying the molar proportions of three precursors (thiocarbazide, p-phthalaldehyde, and triphenylphosphite). Nano-composites (CuO-MAP and CuO-BAP) are successfully elaborated by impregnation of the matrices with copper sulfate solution before processing to in situ precipitation of copper in alkaline solution (simultaneous partial Cu reduction). The sorbents are characterized using: TEM, XRD, elemental analysis, SEM-EDX, BET, titration (pHPZC), XPS and FTIR analyses. Uranium sorption properties are compared for the different sorbents through the study of pH effect (optimum close to 4.5), the uptake kinetics (equilibrium reached in 60 min) and sorption isotherms. Uptake kinetics are finely fitted by the pseudo-second order rate equation (and the resistance to intraparticle diffusion). The sorption isotherms are modeled by the Langmuir equation with maximum sorption capacity (mmol U g−1) decreasing according to CuO-BAP(1.15) ≫ CuO-MAP(0.80) > BAP(0.74) ≫ MAP(0.50). The enhanced textural properties and the increase in the density of sorption sites (probably completed by a better steric arrangement for improved reactivity) may explain this ranking. The sorption is endothermic: sorption capacity and affinity coefficient increase with temperature. Uranium is readily desorbed from loaded-sorbents (efficiency > 98 %) using either HCl (0.2 M) solution or acidified urea (0.25 M) solution (pH 2.5) for aminophosphonate matrices and nano-composites, respectively. The type of sorbent does not affect the stability at recycling: at the sixth cycle, the loss in sorption and desorption performances varies by 6.2–7 % and 4.2–4.9 %, respectively. CuO-BAP sorbent shows high potential for uranium recovery from complex acid ore leachate. The broad spectrum of bound metals does not allow producing a pure yellow cake after ammonia precipitation of eluate (containing up to 15–22 % impurities).

Fabrication of novel 3D PEI-functionalized ZIF-8@alginate aerogel composites for efficient elimination of Pb(II) and Cd(II) from aqueous solution

ZIF-8, a metal-organic framework, has large sorption capacities for a series of heavy metals. However, it is difficult to be separated from aqueous solution, limiting its practical application in wastewater treatment. Herein, ZIF-8 was in-situ grown on the polyethyleneimine-functionalized alginate to construct the ZIF-8 @ALG-PEI aerogels with a three-dimensional network structure. This synthesis strategy not only overcomes the above-mentioned defects of ZIF-8, but also provides more functional groups, pores, and channels. The synthesized ZIF-8 @ALG-PEI aerogels exhibit outstanding removal performance towards Pb(II) and Cd(II) with maximum sorption capacity values of 295.986 and 249.838 mg·g−1, respectively. The sorption of Pb(II) and Cd(II) on ZIF-8 @ALG-PEI is strongly affected by pH, but little influenced by ionic strength. In the multi-component sorption systems, ZIF-8 @ALG-PEI shows better sorption affinity and selectivity for Pb(II) than for Cd(II). The three-dimensional network structure constructed by alginate makes Pb(II) and Cd(II) easier to contact with the surfaces of ZIF-8 @ALG-PEI. The strong surface complexation of the O- and N-containing functional groups provided by ZIF-8 and PEI with Pb(II) and Cd(II) makes the largest contribution to the removal of Pb(II) and Cd(II) by ZIF-8 @ALG-PEI. In summary, the experimental findings of this work prove that the synthesized ZIF-8 @ALG-PEI aerogels have promising applications in practical wastewater treatment.

The Effect of Modifying Canadian Goldenrod (Solidago canadensis) Biomass with Ammonia and Epichlorohydrin on the Sorption Efficiency of Anionic Dyes from Water Solutions.

This study examined the effect of modifying Canadian goldenrod (Solidago canadensis) biomass on its sorption capacity of Reactive Black 5 (RB5) and Reactive Yellow 84 anionic dyes. The scope of the research included the characteristics of sorbents (FTIR, elementary analysis, pHPZC), the effect of pH on dye sorption efficiency, sorption kinetics, and the maximum sorption capacity (describing the data with Langmuir 1 and 2 and Freundlich models). FTIR analyses showed the appearance of amine functional groups in the materials modified with ammonia water, which is indicative of the sorbent amination process. The amination efficiency was higher in the case of materials pre-activated with epichlorohydrin, which was confirmed by elemental analysis and pHPZC values. The sorption efficiency of RB5 and RY84 on the tested sorbents was the highest in the pH range of 2-3. The sorption capacity of the goldenrod biomass pre-activated with epichlorohydrin and then aminated with ammonia water was 71.30 mg/g and 59.29 mg/g in the case of RB5 and RY84, respectively, and was higher by 2970% and 2510%, respectively, compared to the unmodified biomass. Amination of biomass pre-activated with epichlorohydrin can increase its sorption capacity, even by several dozen times.

The Use of Exoskeletons and Molts of Farmed Mealworm (Tenebrio molitor) for the Removal of Reactive Dyes from Aqueous Solutions

The study aim was to test the applicability of exoskeletons and molts from mealworm (Tenebrio molitor) cultures as sorbents for anionic dyes: Reactive Black 5 (RB5) and Reactive Yellow (RY84). Factors investigated included: characteristics of sorbents (FTIR, pHPZC), the influence of pH on sorption efficiency, sorption kinetics (pseudo-first, pseudo-second-order, intraparticle diffusion models), and determination of the maximum sorption capacity (Langmuir 1, Langmuir 2, Freundlich, and Dubinin–Radushkevich models). The sorption efficiency of anionic dyes on the tested sorbents was the highest at pH 2. The time needed to reach the sorption equilibrium for both dyes was 120–150 min. The sorption kinetics of the dyes were best described by the pseudo-second-order model. Maximum sorption capacity data showed the best fit to Langmuir 2 isotherm, suggesting that at least two types of sorption centers played an important role in dye sorption. Presumably, for both of the tested sorbents, the active sites in question were protonated amine (-NH3+), acetamide (NH2COCH3+), and hydroxyl groups (-OH2+) of chitin and protein. The maximum RB5 and RY84 sorption capacity of the tested sorbents was 78.70 mg/g and 60.49 mg/g, respectively, for mealworm exoskeletons, as well as 55.72 mg/g and 44.25 mg/g, respectively, for mealworm molts.

Synergistic impacts of ferromanganese oxide biochar and optimized water management on reducing Cd accumulation in rice

Ferromanganese oxide biochar composite (FMBC) is an efficient remediation material for cadmium -contaminated soils. However, the effect of FMBC under varied water managements on the remediation of Cd-polluted soil is unclear. In this study, we conducted both incubation and field experiments to investigate the combined effects of corn-stover-derived biochar modified with ferromanganese on the immobilization and uptake of Cd by rice under continuous aerobic (A), aerobic-flooded (AF), and flooded-aerobic (FA) water management regimes. The results showed that loading iron-manganese significantly increased the maximum sorption capacity (Qm) of Cd on FMBC (50.46 mg g−1) due to increased surface area, as compared to the pristine biochar (BC, 31.36 mg g−1). The results revealed that soil Eh and pH were significantly affected by FMBC and it’s synergistic application with different water regimes, thus causing significant differences in the concentrations of DTPA-extractable Cd under different treatments. The lowest DTPA-extractable Cd content (0.28–0.46 mg−1) was observed in the treatment with FMBC (2.5 %) combined FA water amendment, which reduced the content of available Cd in soil by 2.63–28.4 %. Moreover, the treatments with FMBC-FA resulted the proportion of residual Cd increased by 22.2 % compared to the control. Variations in the content and fraction of Cd had a significant influence on its accumulation in the rice grains. The FMBC-FA treatments reduced the Cd concentration in roots, shoots and grains by 37.97 %, 33.98 %, and 53.66 %, respectively, when compared with the control. Predominantly because of the reduction in Cd biological toxicity and the improved soil nutrient content, the combined application increased the biomass and yield of rice to some extent. Taken together, the combination of the Fe-Mn modified biochar and flooded-aerobic water management may potentially be applied in Cd-polluted soil to mitigate the impacts of Cd on rice production.

STUDY OF SORBSION PROPERTIES OF COPPER (II) ION WITH CHITOSAN BASED SORBENT

Over the past few decades, a significant increase in the use of heavy metals has led to an increase in the amount of metals in the aquatic environment. For living organisms, among heavy metals, copper (II) is one of the toxic metals and one of the most common environmental pollutants. Excessive concentrations of Cu2+ ions can cause various diseases and intoxications in humans. In this regard, the use of absorbents for the sorption of metals is both an economically and technologically efficient method. Quaternized natural polymer chitosan was used as a sorbent to study the sorption properties of copper (II) ion. During the research, the optimal conditions of the sorption process was determined, pH effect of the environment, initial concentration of the metal on the sorption process were studied. The sorption capacity of the synthesized sorbent towards the Cu (II) ion was studied and it was determined that the maximum sorption capacity equal to 255 mg/g was at pH=4. Moreover the influence of copper (II) ion concentration on the sorption process was studied. It was found that the sorption capacity and sorption degree of the sorbent increase with an increase in the concentration of the Cu2+ ion in the solution. It was determined that the maximum sorption capacity was 406 mg /g, which corresponds to the concentration of copper (II) ion, equal to 10∙10-2 mol/L. The results show that quaternized chitosan-based sorbent can be successfully used for the sorption of Cu (II) ion

PROMISING MULTIFUNCTIONAL ANIONITES FOR THE EXTRACTION OF CHROMIUM (VI) IONS

30% of the chromium ore reserves in the world are concentrated in Kazakhstan, during the processing of which large volumes of wastewater containing toxic chromium salts, are formed. Сhromium is one of the priority components both in terms of emission and toxicity (for Cr(VI), the maximum permissible concentration is 0.05 mg/l). The compounds of chromium (III) and especially chromium (VI) have a general toxic, allergenic, carcinogenic, mutagenic effect on the human body, and are among the most dangerous pollutants for the environment. The aim of this work is to develop a technological scheme for the extraction of Cr (VI) ions by multifunctional ion exchangers. Methods. Anionite, based on diglycidyl ether of dioxyphenylpropane, allylglycidyl ether and polyethylenimine – Ionite No. 1 has been synthesized by polycondensation, and epoxyamine has been synthesized from benzylamine and epichlorohydrin, by the condensation of which Ionite No.2 has been obtained with polyethylenimine. The sorption of chromium ions on newly synthesized anionites has been studied, using model solutions with the concentrations of 25, 50, 75 and 100 mg/l Cr (VI). Results and discussion. It has been established that Ionite No.1 exhibits greater affinity for Cr (VI) ions. So, its maximum sorption capacity is 13.5, and that of Ionite No.2 is 11.7 mg/g. Conclusion. We have proposed a basic technological scheme of a desalination plant, consisting of modular units: reagent-mechanical, sorption, membrane, ion exchange and bacterial purification. It has been established that reagentmechanical purification is the initial stage of water treatment, designed to isolate insoluble coarse- and fine-dispersed impurities.

Novel material from immobilization of magnesium oxide and cetyl trimethyl ammonium bromide nanoparticles onto waterworks sludge for removing methylene blue from aqueous solution

Utilizing the waterworks sludge byproduct in the treatment of wastewater contained methylene blue dye is one approach that has been taken in an effort to lessen the difficulties that are associated with managing such byproduct. The prime aim of this work is manufacturing of novel sorbent from co-precipitation of magnesium oxide nanoparticles on the surfaces of waterworks sludge in the existence of cetyl trimethyl ammonium bromide surfactant. Surfactant 0.04 g/50 mL, dose of sludge 2 g/50 mL, and pH 12 were the most efficient preparation parameters to remove 75.31% of adopted dye. The adsorption studies were conducted under various conditions of contact time (0–240 min), concentration of dye (10–300 mg/L), sorbent mass (0.05–1.5 g), and solution pH (3–12). The best values of batch parameters were identical to the highest percentages of contaminant removal. Results proved that the magnesium oxide nanoparticles are attached to the sludge surfaces. Freundlich and pseudo-second-order models have perfectly described sorption results with 59.92 mg/g maximum sorption capacity. The breakthrough curves can be accurately described by the Bohart-Adams model. The outputs of continuous tests have been paved the way for future usage of the prepared sorbent in the field permeable reactive barrier technology.

An innovative approach to synthesize graft copolymerized acetylacetone chitosan/surface functionalized alginate/rutile for efficient Ni(II) uptake from aqueous medium

In this study, an innovative approach is followed to synthesize graft copolymerized chitosan with acetylacetone (AA-g-CS) through free-radical induced grafting. Afterwards, AA-g-CS and rutile have been intercalated uniformly into amino carbamate alginate matrix to prepare its biocomposite hydrogel beads of improved mechanical strength having different mass ratio i.e., 5.0 %, 10.0 % 15.0 % and 20.0 % w/w. Biocomposites have been thoroughly characterized through FTIR, SEM and EDX analysis. Isothermal sorption data showed good fit with Freundlich model as conferred from regression coefficient (R2 ≈ 0.99). Kinetic parameters were evaluated through non-linear (NL) fitting of different kinetic models. Experimental kinetic data exhibited close agreement to quasi-second order kinetic model (R2 ≈ 0.99) which reveals that chelation between heterogeneous grafted ligands and Ni(II) is occurring through complexation. Thermodynamic parameters were evaluated at different temperatures to observe the sorption mechanism. The negative values of ΔG° (−22.94, −23.56, −24.35 and − 24.94 kJ/mol), positive ΔH° (11.87 kJ/mol) and ΔS° (0.12 kJ/molK−1) values indicated that the removal process is spontaneous and endothermic. The maximum monolayer sorption capacity (qm) was figured as 246.41 mg/g at 298 K and pH = 6.0. Hence, 3AA-g-CS/TiO2 could be better candidate for economic recovery of Ni(II) ions from waste effluents.

Magnetic sporopollenin supported magnesium nanoparticles for removal of tetracycline as an emerging contaminant from water.

Since the release of antibiotics as emerging contaminants into the environmental water can cause severe difficulties for human health, their removal from the water is necessary. In this regard, a novel environmentally friendly adsorbent was developed based on green sporopollenin, which was magnetized and modified with magnesium oxide nanoparticles to produce MSP@MgO nanocomposite. The newly developed adsorbent was applied to remove tetracycline antibiotic (TC) from aqueous media. The surface morphology of the MSP@MgO nanocomposite was characterized using FTIR, XRD, EDX, and SEM techniques. The effective parameters of the removal process were studied, and it was confirmed that the chemical structure of TC was highly affected by changes in pH solution due to different pKa; therefore, the results showed that pH 5 was the optimum. Also, the maximum sorption capacity of MSP@MgO for TC for adsorption was obtained at 109.89 mg.g-1. In addition, the adsorption models were investigated, and the process was fitted with the Langmuir model. Thermodynamic parameters showed that the process was spontaneous (ΔG < 0), endothermic (ΔH > 0) and the adsorption mechanism was following the physisorption mechanism at room temperature.

Chitosan decorated zirconium metal-organic framework for collaborative adsorption and photocatalytic degradation of methylene blue and methyl orange

A type of crystalline porous material known as zirconium metal-organic frameworks (UiO-66) is made up of organic carboxylate ligands and inorganic zirconium clusters. The UiO-66 has consistent pore sizes, large porosities, exceptional adsorption capabilities, and particular functional groups for increasing dye adsorption. This study reports the synthesis of Zirconium metal-organic framework (UiO-66) and chitosan composite of zirconium metal−organic framework (CS/UiO-66) for potential adsorption of methyl orange (MO) and methylene blue (MB) dyes from the aqueous media and additional, excellent photodegradation capability of the synthesized material towards selected dyes. The synthesized materials were successfully characterized for structural, morphological, surface and thermogravimetrical analysis. The exclusion of dyes onto the CS/UiO-66 followed the trend MB (2321 mg/g) > MO (900 mg/g) respectively. The maximum sorption and degradation capacity of the CS/UiO-66 were increased by 5–10 times after its composite with chitosan (CS) and the affinity of the dyes towards the different adsorbents followed the sequence CS/UiO-66 > UiO-66 > CS which is parallel to their surface properties. The negative values of the entropy i.e., − 382 for MB and − 249 for MO affirmed the controlled versatility of the MO, and MB onto CS/UiO-66 whereas the isosteric heat of adsorption i.e., − 201 kJ/mol for MB and − 153 kJ/mol for MO illustrated the exothermicity of the adsorption process. The intraparticle diffusion and Richenberge kinetic models demonstrated that pore diffusion dominates in the adsorption of MB while film diffusion has a greater involvement in the MO adsorption of CS/UiO-66. Moreover, the photocatalytic degradation study indicated that the pH and H2O2 play a significant part in the deprivation of dyes. While GC-MS analysis revealed that the photocatalytic degradation of MB resulted in the formation of six TPs. The toxicity of these TPs of MB was evaluated by ECOSAR program and the results showed that the TPs were less toxic than the parent MB molecule.

Green synthesis of graphene-oxide based nanocomposites for efficient removal of methylene blue dye from wastewater

Water-soluble dyes are a common problem in wastewater treatment, requiring highly efficient methods for removal. In this study, novel sustainable adsorbents made from graphene-oxide (GO) and other materials, such as eggshell-derived calcium oxide nanoparticles (CaONPs-ES), fish bone calcium oxide nanoparticles (CaONPs-FB), and durian shell activated carbon (DSAC) were synthesized, characterized, and demonstrated for soluble dye removal from wastewater. Fermented maize grain extract (MES) was used as a green cross-linker in the synthesis process. The resulting nanocomposites, GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC, showed promising adsorption capabilities for methylene blue (MB) dye removal from aqueous environments. The prepared nanocomposites (GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC) were characterize using state-of-art instrumental techniques. The BET measurement revealed that the nanocomposites surface areas were enhanced due to the cross-linking phenomenon, improving their adsorption capability towards MB dye treatment. The adsorption data of GO@CaONPs-FB/DSAC and GO@CaONPs-ES/DSAC was well fitted to the Harkins-Jura and Freundlich models, respectively. The maximum sorption capacities of GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC were 1274.5 and 689.7 mg/g, respectively. The MB dye removal mechanism was driven by π-π interaction, hydrogen bonding, electrostatic attraction and physical interactions and the adsorption process of the nanocomposites followed pseudo-second-order kinetics. The adsorptive performance of the nanocomposites was stable, showing ∼96.45 % and ∼85.18 % after 10 successive cycles for GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC respectively. Cost evaluation revealed that bulk synthesis of GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC nanocomposites is cost-effective for treating large quantities of MB contaminated water and other potential dyes as well. Finally, the independent and synergetic contributions between pH, adsorbent dosage and temperature on MB removal by GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC were studied and optimized by central composite design (CCD) an aspect of the response surface methodology (RSM). Finally, this study suggests that the novel green cross-linking approach has a significant impact in enhancing the adsorptive performances of the developed nanocomposites to effectively capture MB from aqueous environment.

Sustainable production of flocculant-containing bacterial cellulose composite for removal of PET nano-plastics

Polyethylene terephthalate (PET) nano-plastics (PNP) is a major source of water pollution which in turn causes health issues in humans. There is no effective method to completely remove PNP from wastewater. In this study, bacterial cellulose (BC)/bacterial flocculant (BF) composite was produced from PNP ammonia hydrolysate through the co-cultivation of Taonella mepensis WT-6 and Diaphorobacter nitroreducens R9. The structural characterization of the BC/BF composite through Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and thermal and mechanical analyses demonstrated that the amino-group-rich flocculant produced by the D. nitroreducens R9 was incorporated into the BC network without interfering the self-aggregation of cellulose fibrils. Fast PEP removal was observed in pure and tap water with maximum sorption capacity (Qmax) of 124.65 mg/g and 115.60 mg/g, respectively, whereas least removal was observed for campus lake water with a Qmax value of 84.78 mg/g. A 10 mM SO42− significantly decreased the adsorption capacity to 44.52 mg/g, while 2 mM Ca2+ contributed to the adsorption of PNP with a maximum adsorption capacity of 144.78 mg/g at pH 6.0. The potential adsorption mechanism was investigated through adsorption kinetic studies, isothermal models, and thermodynamics studies. The adsorbed BC/BF was recycled by desorbing PNP with ammonia water, and the eluent could be utilized as a medium for sustainable production of BC/BF. The reusable BC/BF adsorbent produced through the co-culture technique can effectively control PNP pollution.

Carbon Adsorbents Obtained from Pistachio Nut Shells Used as Potential Ingredients of Drinking Water Filters.

Water resources are increasingly degraded due to the discharge of waste generated in municipal, industrial and agricultural areas. Therefore, the search for new materials enabling the effective treatment of drinking water and sewage is currently of great interest. This paper deals with the adsorption of organic and inorganic pollutants on the surface of carbonaceous adsorbents prepared by thermochemical conversion of common pistachio nut shells. The influence of the direct physical activation with CO2 and chemical activation with H3PO4 on parameters, such as elemental composition, textural parameters, acidic-basic character of the surface as well as electrokinetic properties of the prepared carbonaceous materials was checked. The suitability of the activated biocarbons prepared as the adsorbents of iodine, methylene blue and poly(acrylic acid) from the aqueous solutions was estimated. The sample obtained via chemical activation of the precursor turned out to be much more effective in terms of all the tested pollutants adsorption. Its maximum sorption capacity toward iodine was 1059 mg/g, whereas in relation to methylene blue and poly(acrylic acid) 183.1 mg/g and 207.9 mg/g was achieved, respectively. For both carbonaceous materials, a better fit to the experimental data was achieved with a Langmuir isotherm than a Freundlich one. It has also been shown that the efficiency of organic dye, and especially anionic polymer adsorption from aqueous solutions, is significantly affected by solution pH and temperature of the adsorbate-adsorbent system.

Praseodymium(III) Removal from Aqueous Solutions Using Living and Non-Living Arthrospira platensis Biomass

Praseodymium, the sixth-most abundant rare-earth element, is widely used in the aircraft industry for the elaboration of refractory substances, coloring materials, lighting equipment, and fiber optical cables. Living and non-living Arthrospira platensis biomass was applied for Pr(III) removal from aqueous solutions. In bioaccumulation experiments, the effect of Pr(III), introduced into the medium in a concentration range of 10–30 mg/L, on biomass productivity, biochemical composition, and antioxidant activity was assessed. The biomass showed high accumulation capacity (more than 99%) toward Pr(III). Supplementation of the cultivation medium with Pr(III) led to a decrease in carbohydrate and lipid content, but it did not significantly influence biomass productivity or the content of proteins and pigments. In experiments with non-living biomass, the effect of pH, Pr(III) concentration, temperature, and contact time on the efficiency of metal removal was investigated. The maximum uptake of Pr(III) was achieved at pH 3.0 after 3.0 min of interaction. The equilibrium data were explained using the Langmuir and Freundlich models, while the kinetics of the process was described by applying pseudo-first-order, pseudo-second-order, and Elovich models. The maximum sorption capacity of Arthrospira platensis biomass calculated from the Langmuir model was 99.3 mg/g. According to the thermodynamic calculations, the process of Pr(III) removal was spontaneous and exothermic in nature. The obtained data can be used for the development of environmentally-friendly technology for Pr(III) recovery from wastewater as well as to understand the effect of Pr(III) on aquatic organisms.