In this work, cobalt-aluminum-layered double hydroxide (CoAl) and its bentonite composite (Bent-CoAl) were utilized for adsorption of Cr(VI) from water. Incorporation of bentonite into layers of CoAl ...resulted in significant improvement in the adsorptive performance with increased BET surface area, without damaging LDH structure. The adsorption process was described by Freundlich isotherm and pseudo-second-order kinetic models. The mechanism of Cr(VI) sorption mainly involved electrostatic and chemical interactions with maximum Cr(VI) sorption value of 211.86 mg/g. This suggests that synergistic effect of bentonite into CoAl provided a superior adsorbent for decontamination of heavy metals.
In the last three decades, pharmaceutical research has increased tremendously to offer safe and healthy life. However, the high consumption of these harmful drugs has risen devastating impact on ...ecosystems. Therefore, it is worldwide paramount concern to effectively clean pharmaceuticals contaminated water streams to ensure safer environment and healthier life. Nanotechnology enables to produce new, high-technical material, such as membranes, adsorbent, nano-catalysts, functional surfaces, coverages and reagents for more effective water and wastewater cleanup processes. Nevertheless, nano-sorbent materials are regarded the most appropriate treatment technology for water and wastewater because of their facile application and a large number of adsorbents. Several conventional techniques have been operational for domestic wastewater treatment but are inefficient for pharmaceuticals removal. Alternatively, adsorption techniques have played a pivotal role in water and wastewater treatment for a long, but their rise in attraction is proportional with the continuous emergence of new micropollutants in the aquatic environment and new discoveries of sustainable and low-cost adsorbents. Recently, advancements in adsorption technique for wastewater treatment through nanoadsorbents has greatly increased due to its low production cost, sustainability, better physicochemical properties and high removal performance for pharmaceuticals. Herein, this review critically evaluates the performance of sustainable green nanoadsorbent for the remediation of pharmaceutical pollutants from water. The influential sorption parameters and interaction mechanism are also discussed. Moreover, the future prospects of nanoadsorbents for the remediation of pharmaceuticals are also presented.
MgAl-layered hydroxide intercalated date-palm biochar composites (B-MgAl-LDH) functionalized with improved textural properties and surface functionalities were fabricated by a facile co-precipitation ...technique and fully characterized by various techniques. The B-MgAl-LDH were employed for enhanced aqueous uptake of methylene blue (MB) (Langmuir qmax = 302.75 mg/g at 100 mg/L in 180 min), compared with the virgin biochar (qmax = 206.61 mg/g in 480 min). Higher MB removal is attributed to the excellent hybridization of the two adsorbents which resulted in substantial improvement in surface area, micropore volume, and abundant surface functional groups, facilitating fast and better adsorptive removal of MB from water. The B-MgAl-LDH showed good adsorptive performances of MB at varied pH values (4–10). The kinetic data were best described by the pseudo-2nd-order while the adsorption isotherms fitted best to the Langmuir model. The thermodynamic parameters indicated the exothermic nature of MB adsorption and reduction in the degree of randomness at the B-MgAl-LDH /MB interface. The adsorption mechanism of MB onto biochar-MgAl composite is mainly governed by the surface adsorption and internal pore diffusion along with chemical and ion-exchange interaction as confirmed by BET, SEM, and FTIR characterization after the MB adsorption. Therefore, the modification of date palm biochar with MgAl via co-precipitation method is an effective approach to produce B-MgAl-LDH composite for the excellent removal of toxic dyes from wastewater streams.
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•A sustainable biochar decorated LDH composites adsorbent was produced from a MgAl-LDH precursor.•Biochar-MgAl composite exhibit surface area (441.06 mg/g), micropore volume (0.360 cm3/g) and abundant functional groups.•The B-MgAl composite reveal rapid MB uptake with sorption capacity improved to 302.75 mg/g related to biochar (206.61 mg/g).•Internal pore filling, ion-exchange and chemical interactions mainly involved in MB adsorption.
In this research work, a novel hybrid composite consisting of biochar (B), layered double hydroxide (CuFe) and chitosan (CS) (B-CuFe-CS) was produced using an ultrasonication-assisted ...co-precipitation method. The resultant composite was employed for adsorptive removal of Eriochrome black T (EBT) from water. Physicochemical characterization indicated that the B-CuFe-CS containing 10 wt % CS exhibited a heterogeneous structure with better crystallographic and textural characteristics. The B-CuFe-CS with abundant surface functionalities (-CO, -C-O, –OH, –NO3, and MMO), facilitates faster and enhanced removal of the EBT. The kinetic results showed better fitting to the pseudo-second order model, and equilibrium was achieved within 30 min. Equilibrium data was well explained by Langmuir and Redlich Peterson isotherm models (R2 > 0.98), indicating the EBT removal onto B-CuFe-CS followed monolayer adsorption. The maximum adsorption capacity was 806.4 mg/g, which was higher than pristine B–CuFe (476.19 mg/g) and many other adsorbents. The spectroscopic analysis (FTIR and XPS) and experimental results suggested that EBT adsorption is mainly governed by electrostatic, chemical and anion-exchange interactions. It is evident from these results that coupling B–CuFe composite with bio-filler (chitosan) resulted in an efficient bio-adsorbent to effectively purify dye-contaminated water streams.
•Sustainable B-CuFe-CS biocomposite was fabricated.•B-CuFe-CS composite shows superior adsorption performance towards Eriochrome Black T (EBT).•Incorporated CS improved the surface functionality of the composite that resulted in enhanced EBT adsorption.•B-CuFe-CS EBT adsorption capacity (806.4 mg/g) was 1.5 times higher than B–CuFe (476.19 mg/g).
Due to their industrial relevance, phenolic compounds (PC) are amongst the most common organic pollutants found in many industrial wastewater effluents. The potential detrimental health and ...environmental impacts of PC necessitate their removal from wastewater to meet regulatory discharge standards to ensure meeting sustainable development goals. In recent decades, one of the promising, cost-effective and environmentally benign techniques for removal of PC from water streams has been adsorption onto sewage sludge (SS)-based activated carbon (SBAC). This is attributed to the excellent adsorptive characteristics of SBAC and also because the approach serves as a strategy for sustainable management of huge quantities of different types of SS that are in continual production globally. This paper reviews conversion of SS into activated carbons and their utilization for the removal of PC from water streams. Wide ranges of topics which include SBAC production processes, physicochemical characteristics of SBAC, factors affecting PC adsorption onto SBAC and their uptake mechanisms as well as the regeneration potential of spent SBAC are covered. Although chemical activation techniques produce better SBAC, yet more research work is needed to harness advances in material science to improve the functional groups and textural properties of SBAC as well as the low performance of physical activation methods. Studies focusing on PC adsorptive performance on SBAC using continuous mode (that are more relevant for industrial applications) in both single and multi-pollutant aqueous systems to cover wide range of PC are needed. Also, the potentials of different techniques for regeneration of spent SBAC used for adsorption of PC need to be assessed in relation to overall economic evaluation within realm of environmental sustainability using life cycle assessment.
In this work, engineered biochar decorated layered double hydroxides and cellulose nanocrystals (B–CuFe–CNC) biocomposites were synthesized by the facile ultrasonicated-co-precipitation technique. ...The biocomposite was investigated for purification of Eriochrome Black T (EBT) dye from water. The characterization results showed that the presence of CNC in biochar-layered double hydroxides resulted in a two-dimensional rod-like structure with excellent crystallinity, improved surface functionalities, and provides an attractive platform for the enhanced adsorption of azo anionic dye molecules. The adsorption system was appropriately demonstrated by the BBD-RSM (R2 > 0.994). The biocomposite exhibited higher EBT adsorption in the acidic pH range (2–5) due to strong electrostatic and chemical interactions. The kinetic and isotherm results were well demonstrated by pseudo-second order, Freundlich, and Redlich Peterson models. The maximum adsorption capacity of biocomposite was 876.2 mg/g achieved within 45 min. The spectroscopic analyses imply that the high removal of EBT by biocomposite is mainly governed by electrostatic attraction, hydrogen bonding, and chemical/metal complexation mechanisms. The biocomposite maintained high EBT removal after six successive adsorption cycles and excellent dye adsorption in the different water matrices. The results suggest that tailoring biochar properties with layered double hydroxide and CNC is a promising way for the enhanced removal of dye contaminants from wastewater.
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•Biochar-CuFe-CNC biocomposites were fabricated by simple co-precipitation method.•The biocomposite exhibited superior adsorption of Eriochrome Black T(EBT) dye.•The adsorption capacity of B-CuFe-CNC was five and three folds higher than biochar and CuFe LDH.•The presence of CNC improved the surface functionality and hydrophilicity.
Starch-NiFe-layered double hydroxide (S/NiFe-LDH) composite was prepared via co-precipitation method and employed as an adsorbent for the removal of anionic dye methyl orange (MO) from aqueous ...solution. Two hybrids with different ratio of starch and NiFe-LDH were prepared i.e. S/NiFe-LDH (1:1) and S/NiFe-LDH (2:1) and their adsorption performance was compared with NiFe-LDH. The synthesized nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The effects of influential adsorption parameters such as pH, initial MO concentration contact time and adsorbent dosage on the removal of MO were studied. The starch-NiFe-LDH composite was efficient in removing MO from water and maximum removal of 99 and 90% was observed at pH3 by S/NiFe-LDH (1:1), S/NiFe-LDH (2:1), respectively. The maximum adsorption capacities of NiFe-LDH, S/NiFe-LDH (2:1) and S/NiFe-LDH (1:1), calculated from Langmuir isotherm, were 246.91mg/g, 358.42mg/g, 387.59mg/g respectively. The adsorption kinetics of MO on the surface of S/NiFe-LDH composites was best fitted by pseudo-second-order model. Starch-NiFe-LDH was easily regenerated with aqueous solution of NaOH with a minor loss in adsorption capacity up to four cycles.
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•Starch-NiFe layered double hydroxide composites were prepared via co-precipitation method.•Effective adsorption of methyl orange on starch-NiFe composite and excellent regeneration potential•Qmax onto NiFe-LDH, S/NiFe-LDH (1:1) and S/NiFe-LDH (2:1) were 246.91, 358.42, and 387.59mg/g, respectively.•Redlich Peterson isotherm model and pseudo second order kinetic model suitably described the adsorption process.
Industrial and hospital effluents are often dumped into water streams. Since these effluents consist of higher concentrations of pharmaceutical residues, they are difficult to eliminate using ...conventional wastewater treatment plants (WWTP) and are hazardous to humans and the environment. In contrast, biological treatment of wastewater is an environmentally friendly method that forms less sludge and is relatively inexpensive. However, like WWTP, biological treatment is less efficient in eliminating pharmaceutical residue from wastewater. Therefore, several other treatment options have been investigated globally, e.g., electro-Fenton (EF), and processes such as photocatalytic oxidation (PCO). Among them, the advanced oxidation processes, such as the Fenton process, were found to be comparatively more effective at the removal of pharmaceutical residues and have gained the continued attention of researchers. However, a primary disadvantage of the Fenton process is its significantly high energy consumption that makes its large-scale deployment cost-prohibitive. To overcome this challenge, several integrated treatments have been proposed by many scientific communities. This paper intends to review the available literature to explore the remediation of pharmaceutical wastewater using different versions of the Fenton oxidation process and finds that the integration of the Fenton's oxidation process with a biological process results in the complete degradation of the pharmaceutical residue in wastewater.
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•PWW treatment by integrated-Fenton oxidation was reviewed.•Fenton oxidation method enhances the biodegradability and removal of PWW.•Key performance indicators affecting the overall PWW treatment are presented.•Several key aspects of cost-effectiveness are evaluated.•Further prospects for research in environmental applications are discussed.
•Two steel dust were NaOH-modified and physicochemical characterized;•The adsorbents were applied to remove Eriochrome Black-T (EBT) and Tetracycline (TC);•All isotherms were favorable and the ...removal of pollutants increases as the temperature rises;•After five cycles of regeneration the removal percentage was more than 80%;•ANN showed up a promising tool in predicting the adsorption capacity at equilibrium.
This study focuses on the use of chemically modified steel dust-based adsorbent to remove Eriochrome Black-T (EBT) and Tetracycline (TC) from water. The adsorption isotherm, kinetic modeling, thermodynamic and regeneration studies were conducted. The adsorption process was modeled using Artificial Neural Network. The adsorption kinetics were well fitted by a pseudo-second-order kinetic model and Redlich-Peterson model. The maximum adsorption capacity for TC was 19.78 mg.g−1 (Mod-AL) and 14.37 mg.g−1 (ModAR), and for EBT was 90.71 mg.g−1 (Mod-AL) and 119.02 mg.g−1 (Mod-AR). The thermodynamic evaluation indicated the adsorption was endothermic, spontaneous, and did not cause modification onto an adsorbent surface. The artificial neural based network has predicted the adsorption capacity at equilibrium with a high degree of accuracy quantified with minimum mean squared error of 1.2240 and coefficient of determination of 0.9990. FTIR spectra of free and dye adsorbed adsorbents revealed a slight shift in the peak positions, indicative of the interaction of adsorbents functionalities with the EBT and TC. The XRD spectra of Mod-AL and Mod-AR exhibited fewer sharp peaks signals, suggesting the amorphous nature of these adsorbents. The thermogravimetric analysis (TGA) of these adsorbents revealed their higher thermal stablity, with less than 10 % weight loss up to heating to 900 °C.
This study reports the synthesis of date palm waste-derived biochar (B) supported CuFe layered double hydroxides (CuFe LDH) composite by facile co-precipitation method. The adsorption performance of ...B-CuFe composite was evaluated for the removal of Eriochrome black T (EBT), as a model anionic azo dye, from the aqueous phase. The B-CuFe composites were characterized by FTIR, XRD, TGA, SEM-EDX and BET techniques. Characterization results revealed the synergistic effect of biochar and CuFe LDH has resulted in substantial improvement in physicochemical characteristics (i.e. surface functionality, surface area and surface morphology) of B-CuFe composite, which promotes rapid and improved adsorption of (EBT) from the solution. The B-CuFe composite with 2.5 g loading of biochar onto CuFe LDH - showed better adsorption performance than that of other B-CuFe composites. The adsorption process of EBT onto B-CuFe composite was well described by the RSM models (with R2=0.964–0.999). Acidic pH (2–5) and higher temperature favored the adsorption of EBT onto B-CuFe composite, and almost (70–85%) of EBT was removed from the water within the first 15 min. The highest adsorption capacity, 565.32 mg/g of EBT onto B-CuFe composite, was obtained at pH 2.5 and 45 °C. The adsorption mechanism associated with the strong electrostatic and chemical interactions of EBT sulfonated anions (SO3−) with protonated hydroxyl surface groups (OH2+) of B-CuFe composite. The B-CuFe composite exhibited better EBT removal in the presence of co-existing anions and demonstrated excellent reusability performance (11% reduction) after five successive cycles. The results demonstrated that the B-CuFe composite has a great potential to be employed as a sustainable and cost-effective adsorbent for the purification of dye contaminated water bodies.
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•Sustainable biochar-CuFe composite was fabricated by the coprecipitation method.•B-CuFe exhibited improved physicochemical properties than pure biochar and CuFe.•B-CuFe removed 85% of Eriochrome black T dye from the water in 15 min.•The maximum adsorption capacity of B-CuFe was 565.32 mg/g at 45 °C.•B-CuFe composite exhibited excellent reusability performance.
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