Adsorbent For Wastewater Treatment Research Articles

Computational insights into pectin and chitosan-enhanced MOFs: A green pathway for pollutant remediation

Water contamination with dyes and pharmaceuticals is a major threat to ecological and human well-being. This study highlights the importance of using molecular simulations in designing and predicting the performance of novel adsorbents for wastewater treatment. The research explores the potential of biodegradable polymers like Pectin (PE) and oxidized Chitosan (OCN) in functionalizing a metal-organic framework (MOF) known as UO-66 (Zr) (UO). By incorporating these functional groups, the study aims to improve the adsorption efficiency of UO towards rhodamine B (RHOB, a dye pollutant) and Losartan (LOSA, a pharmaceutical pollutant). Firstly, density functional theory (DFT) calculations were employed to inspect the structures of both pollutants and the modified adsorbents. Subsequently, the research investigated the adsorbents’ various physicochemical characteristics, including fractional free volume, glass transition temperature, and mechanical properties. Finally, molecular dynamics (MD) and Monte Carlo (MC) simulations were accomplished to evaluate the adsorption behaviour of the pollutants on various UO forms (pristine, PE-functionalized, and OCN-functionalized). The study found that all adsorbents showed strong adsorption capabilities, with adsorption energies ranging from −3500 to −4500 kcal/mol for RHOB and −1500 to −2600 kcal/mol for LOSA. Moreover, The drug rejection rate of RHOB for neat is 50 % but increases to 80 % and 90 % with the addition of PE and OCN, respectively, showing their synergistic effect. Similarly, the accumulation rate rises from 6 Å (NH2/UO) to 10 Å (OCN/UO) and 11 Å (PE/UO). For LOSA, the drug rejection rate improves from 30 % to 60 %, while the accumulation rate increases from 4 Å to 8 Å with PE and OCN functionalization. The results demonstrated that functionalizing UO with the chosen biodegradable polymers enhanced its adsorption capacity for both pollutants compared to the pristine form. Notably, the developed adsorbent exhibited a higher affinity towards RHOB dye compared to LOSA pharmaceutical.

Performance and Mechanism of Porous Carbons Derived from Biomass as Adsorbent for Removal of Cr(VI)

To solve the problem of heavy metal hexavalent chromium (Cr(VI)) pollution in water bodies, this study was carried out to prepare nitrogen-doped porous carbon by using bamboo shoots as the raw material and KHCO3 as the activator, which has a good ability to remove Cr(VI) from water bodies. The prepared N-doped carbon materials were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), elemental analysis, and scanning electron microscopy (SEM). The results showed that the prepared carbon material had hierarchical pore structures and abundant functional groups, which is conducive to the adsorption of Cr(VI). The effects of various factors on the adsorption performance of Cr(VI), such as the carbon materials prepared under different conditions, the pH of the initial solution, the concentration of the initial solution, and the contact time between the carbon and Cr(VI), were explored. The results showed that the bamboo shoot-based nitrogen-doped carbon materials, especially BSNC-800 (prepared at 800 °C with a mass ratio of KHCO3 to bamboo shoot of 4:1), performed well in removing Cr(VI) from a water solution. The maximum adsorption of Cr(VI) by BSNC-800 under equilibrium conditions was 385.8 mg g−1 (conditions: at the pH of 2 with the initial concentration of 400 mg L−1). The adsorption kinetics and isotherms were analyzed, and the adsorption mechanism was discussed. It can be found that the adsorption of Cr(VI) by BSNC-800 fits better with the Langmuir isotherm model and the pseudo-second-order kinetic model. The adsorption mechanism between the Cr(VI)-containing solution and BSNC-800 was controlled by membrane diffusion and chemisorption. The results broaden the ways of utilizing biomass resources as precursors of carbon materials, which is significant and helpful for applying biomass carbon materials as adsorbents for wastewater treatment.

Examining the influence of sintering temperatures on the efficiency of 3D-printed natural zeolite for methylene blue dye adsorption

Additive manufacturing technology, with its potential for improved material efficiency, cost reduction, and capability to fabricate complex structures, is increasingly being leveraged in environmental engineering applications. This study harnesses this technology for fabricating natural zeolite adsorbents using an extrusion-based 3D printer, examining the influence of different sintering temperatures (300, 600, 900, and 1200 °C) on the adsorbents' properties. The study finds that samples sintered at 300 °C disintegrated in water, while those at 1200 °C underwent melting, changing their shape. Focus was then shifted to samples sintered at 600 °C (3D-Ze-600) and 900 °C (3D-Ze-900), with the former displaying a remarkable methylene blue (MB) adsorption efficiency of 82.5%, significantly higher than the latter's 20.1%. This disparity in adsorption performance is closely linked to the difference in porosity; the 600 °C samples exhibited a notably higher apparent porosity, which was instrumental in their enhanced adsorption capability. In contrast, the 900 °C samples, despite their lower porosity, showed diminished adsorption efficiency. XRD analysis further revealed that the superior performance of the 600 °C samples could be attributed to their preserved crystalline structure, which was altered in the 900 °C samples. These findings highlight the critical role of sintering temperature in determining the structural and functional properties of 3D-printed zeolites, demonstrating their potential as efficient adsorbents in wastewater treatment and offering valuable insights for optimizing the fabrication process for environmental applications.

Zeolite-carbon composite synthesis and its adsorption property

In this study, SUZ-4 zeolite-carbon composites were synthesized by a one-step hydrothermal method with solid waste, silica fume (SF), aluminum ash (AA), and chitosan (CS), as raw materials. The composites were analyzed by XRD, SEM, FTIR and BET characterizations. The adsorption capacities of the composites for lead ions (Pb2+) and methyl orange (MO) from aqueous solutions were investigated. Based on the adsorption data, pseudo-second-order model and the Freundlich model were suitable to describe the adsorption process of Pb2+ on the composite, while the pseudo-second-order model and the Langmuir model were preferred to describe the adsorption process of MO on the composite. The maximum adsorption capacity of the composite for Pb2+ was 102.2 mg/g at pH=6, and that for MO was 488.3 mg/g at pH=3. The resulting composites have practical applications as adsorbents for wastewater treatment, thus achieving the goal of “waste for waste”.

Preparation of Magnetic Spongy Porous Carbon Skeleton Materials for Efficient Removal of BTEX.

Magnetic polymer microspheres have been extensively utilized as separable and highly efficient adsorbents in wastewater treatment. In this study, a series of novel magnetic spongy porous carbon skeleton materials (Mag-SPCS) have been designed and synthesized by acetonitrile suspension precipitation polymerization, which combines the advantages of the acetonitrile precipitation method and the suspension polymerization method. It was demonstrated that the transformation of the material morphology from microspheres to a porous sponge was achieved by a gradual decrease in the usage amount of ethylene glycol. After N,N-dimethyloctadecylamine (C18) was grafted onto the Mag-SPCS materials, the C18-Mag-SPCS materials with a superhigh saturation adsorption capacity and superfast adsorption efficiency were used for the removal of BTEX (toluene, benzene, and para-xylene) in wastewater. Subsequently, the adsorption properties of the composites with different morphologies were evaluated, and the effect of the usage amount of C18 on the adsorption properties of the C18-Mag-SPCS was further investigated. The maximum adsorption capacities of C18-Mag-SPCS for benzene, toluene, and para-xylene were 714.84, 564.32, and 394.48 mg/g, respectively. The adsorption process was conducted in accordance with the proposed secondary and Langmuir models. Finally, the FTIR, XPS, and XRD characterization results before and after adsorption demonstrated that the adsorption mechanism of toluene onto C18-Mag-SPCS was primarily hydrogen bonding, π-π stacking, and van der Waals forces. These findings of the study indicate that the composite material exhibits an ultrahigh saturation adsorption capacity and ultrafast adsorption efficiency, thereby confirming its considerable potential for application in wastewater treatment.

Life Cyle Assessment of Activated Carbon from Waste Materials as an Adsorbent in Wastewater Treatment

Activated Carbon (AC) has been a great alternative to reduce the cost of the process in wastewater treatment plants (WWTP) but they also have several hidden impacts on the environment. The impact assessment on the waste materials from coconut shells and wood will be identified using the Life Cycle Assessment (LCA) software approach. Through the “Cradle-to-gate” approach, activated carbon made from waste materials is produced and consumed, and its eighteen environmental effects which are fine particulate matter formation, fossil resource scarcity, freshwater ecotoxicity, freshwater eutrophication, global warming, human carcinogenic toxicity, human non-carcinogenic toxicity, ionizing radiation, land use, marine ecotoxicity, marine eutrophication, mineral resource scarcity, human health, terrestrial ecosystem, stratospheric ozone depletion, terrestrial acidification, terrestrial ecotoxicity and water consumption are assessed using the LCA software. This study aims to discover whether the choice of waste material precursors from the Activated Carbon (AC) can help to minimise environmental impacts. The study evaluates the potential benefits of using waste-derived activated carbon in wastewater treatment by comparing the environmental performance of activated carbon obtained from coconut, wood, and coal. This study is based on past studies all around the world. In thirteen of the eighteen impact categories, wood has the greatest environmental impact. Coconut shells on the other hand, has the lowest total environmental impacts, ranking first or second in fifteen among the eighteen environmental categories. The findings help in making choices for environmentally friendly wastewater treatment methods by illuminating the effects of employing waste products as an alternative source of adsorbents.

One stone, two birds: An eco-friendly aerogel based on waste pomelo peel cellulose for the efficient adsorption of dyes and heavy metal ions

To achieve the objective of “waste control by waste”, in this study, a green aerogel adsorbent comprised of pomelo-peel cellulose and sodium alginate (PCC/SA) was prepared through dual-network crosslinking. The resulting 3D hierarchical porous structured PCC/SA aerogel exhibited good structural stability, and kept the morphological integrity during 10 days in a wide pH range (2–10), suggesting its potential for recycling in diverse complex environments. Besides, the superior adsorption capacities for methylene blue (MB) and Cu(II) were observed, with the qm values and adsorption equilibrium times were recorded to be 1299.59 mg/g (300 min) and 287.55 mg/g (120 min), correspondingly. Furthermore, the favorable reusability of the PCC/SA aerogel was also demonstrated, with the removal efficiency for MB remaining almost unchanged (about 94 %) after 10 adsorption-desorption cycles, while there was a slight reduction for Cu(II) from 85.28 % to 72.47 %. XPS and FTIR analysis revealed that electrostatic attraction, hydrogen bonding, cation exchange and coordination were the major adsorption mechanisms. Importantly, the PCC/SA aerogel can be naturally degraded in soil within 10 weeks. Therefore, the as-prepared aerogel bead derived from pomelo peel shows great promise as an adsorbent for wastewater treatment containing dye and heavy metal ions.

Thermodynamic interpretation of cationic dye adsorption onto untreated coffee residues as adsorbents via statistical physics approach

In this current paper, we perform a theoretical examination of adsorption systems undertaken through the application of statistical physics modeling to experimental data Remacryl Red TGL (BR) dye adsorption isotherms onto the untreated coffee residues (UCR) based adsorbents at 298–338 K range. The experimental values exhibited a strong agreement with the predicted values, and the developed model received high approval. Significant parameters are theoretically discussed such as thermodynamic, energetic, and stereographic factors which determine the (BR) adsorption onto UCR. In the pursuit of unraveling the adsorption mechanism, four different models are adopted: a monolayer with one energy (Model 1), a monolayer with two horizontal energies (Model 2), a monolayer with three energies (Model 3) and a double-layer with two vertical energies (Model 4). The analysis considered both steric and energetic parameters associated with the adsorption reaction, namely the number of adsorbed particles per site (n1 and n2), the receptor sites density (N1m and N2m), and the concentration at half-saturation. It appears that the experimental data aligns well with a monolayer model characterized by two energy states. The variations in these factors are examined in relation to the temperature of absorption isotherms. More importantly, the calculation of adsorption energies unequivocally pointed out that the adsorption process is of a chemisorptive nature. Our findings indicate that (UCR) could be utilized as a low-cost alternative adsorbent in wastewater treatment to eliminate the Remacryl Red TGL (BR) dye.

Structural simulation and performance evaluation of a novel synthesized ZIF in the adsorption of MO from aqueous solutions.

Zeolitic imidazolate frameworks (ZIFs) are desirable materials widely applied as adsorbent for wastewater treatment. This study synthesizes and applies a novel structured ZIF with organic ligand of 2-methyl imidazole and metal salt of copper (II) sulfate as adsorbent. Its morphology and structure were investigated using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, field emission scanning electron microscope, energy dispersive X-ray spectrometry, and mapping analysis. After structural analysis, the adsorbent structure was simulated and determined using Avogadro and Gaussian software. The removal efficiency of prepared ZIF in the removal of methyl orange from aqueous solution was evaluated. The effect of pH, the concentration of the dye in solution, dosage of the adsorbent, and the contact time between adsorbent and solution on the methyl orange removal were examined using central composite design of response surface methodology in five levels. The maximum dye removal of 99% was obtained for 2g adsorbent/L, pH of 3.3, and initial dye concentration of 121mg/L after 127min contact time. In addition, to reduce the economic costs and energy consumption, the synthesis time was also reduced and used to show the applicability of the adsorbent prepared and understand its advantages and disadvantages in removing methyl orange dye from aqueous solutions. This molecular adsorbent is stable, and it can be stored for months. On the other hand, this ZIF can be easily recovered and reused many times. In this research, after five times of recovery, there was no significant change in the effectiveness of the adsorbent.

Synthesis and characterization of the Cu(II)-quinoxaline, 3,3-thiodipropionate mixed ligand coordination polymer for the removal of methylene blue from aqueous solution

Herein, we report the removal of methylene blue (MB) dye from water by Cu(II)-quinoxaline, 3,3-thiodipropionate mixed ligand coordination polymer synthesized as [Cu2(TDPH)4(QNX)]·DMF. Characterization of the synthesized material was carried out by elemental analysis, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), BET surface area analysis, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and UV–visible spectroscopy. ν(C = O) and ν(C–O) absorption bands were detected at 1735 and 1093 cm−1, respectively, while ν(C = N) was observed at 1608 cm−1 in the synthesized compound. The synthesized material was used as adsorbent for the removal of MB dye from aqueous solution using batch adsorption technique. The maximum adsorption capacity was found to be 7.9745 mg/g, while the maximum decolorization efficiency for the adsorbent was observed to be 99.04%. Adsorption data from the study fitted the Langmuir isotherm with an R 2 value of 0.9815, while the adsorption kinetics followed the pseudo-second-order kinetic model with an R 2 value of 0.9953. The results obtained from the study, therefore showed that the synthesized materials could be used as adsorbents in wastewater treatment.

The Potential of Electrospun Membranes in the Treatment of Textile Wastewater: A Review.

Water security and industrial wastewater treatment are significant global concerns. One of the main issues with environmental contamination has been the discharge of dye wastewater from the textile and dye industries, contributing to an ever-growing problem with water pollution, poisoning water supplies, and harming the ecosystem. The traditional approach to wastewater treatment has been found to be inefficient, and biosorption techniques and mechanisms have been proven to be a successful replacement for conventional methods. Recent developments have led to the recognition of fibrous materials as an environmentally friendly option with broad application in several industries, including wastewater treatment. This review explores the potential of fibrous materials produced by the electrospinning technique as adsorbents for wastewater treatment, while at the same time, for the removal of adsorbates such as oil, dyes, heavy metals, and other substances, as reported in the literature. Textile wastewater filtering structures, produced by electrospinning, are summarized and the use of synthetic and natural polymers for this purpose is discussed. The limitations of electrospun textile wastewater filtering structures are also mentioned. Electrospun nanofibrous membranes appear to be a very promising route to filter textile wastewater and therefore contribute to water reuse and to reducing the contamination of water courses.

Wastewater sludge-derived hydrochar: Effect of operating conditions, activation, and potential use as adsorbent

Scientific management of wastewater sludge generated from biological wastewater treatment is necessary owing to its high moisture content and poor dewaterability. In this investigation, hydrothermal carbonization technique was implemented as a potential solution for wastewater sludge management. To further improve the surface properties of wastewater sludge-derived hydrochar (synthesized at 250 ℃ for 4 h of reaction time), three activation techniques, namely physical, alkali, and alkali followed by acid activation were implemented. The effect of three activation techniques on the properties of hydrochar was investigated using physico-chemical characterization techniques. The sludge-derived hydrochar activated with KOH (1:1 by weight) followed by HCl treatment (1 M) (HC-KA) showcased highly porous structured material having a surface area of 1119 m2 g–1, which was highest amongst the other activation methods chosen in this investigation. Thus, HC-KA was utilized as an adsorbent to evaluate the adsorptive removal of methylene blue (MB). The MB adsorption process followed Langmuir isotherm (R2 of 0.996) with a maximum adsorption capacity of 192.7 mg g–1 and pseudo-second-order reaction kinetics. The results demonstrated that wastewater sludge-derived activated hydrochar can be considered a promising material as an adsorbent in wastewater treatment.

Revealing the interface chemistry of polyaniline grafted biomass via statistical modeling of multi-component dye systems: optimization, kinetics, thermodynamics, and adsorption mechanism.

The growing need to examine the adsorption capabilities of innovative materials in real-world water samples has encouraged a shift from single to multicomponent adsorption systems. In this study, a novel composite, PANI-g-SM was synthesized by covalently grafting a lignocellulosic biomass, Saccharum munja (SM) with polyaniline (PANI). The as-synthesized composite was investigated for the simultaneous adsorption of cationic (Methylene Blue (MB); Crystal Violet (CV)) and anionic dyes (Reactive Red 35 (RR); Fast Green FCF (FG)) from four single components and two binary systems, MB + RR and CV + FG. Further, the effect and interaction of pH (2-11), dosage (0.01-0.04g/10mL), and initial concentration (0.0313 to 0.1563mmol/L) on the elimination of dyes by PANI-g-SM were studied through a novel design of Box-Behnken of Response Surface Methodology (RSM) technique which was found to be highly useful for revealing the chemistry of interfaces in multi-component systems. The extended Langmuir model for the binary system indicated the presence of synergism, as result the maximum monolayer adsorption capacity increased by 44.44%, 645.83%, 67.88%, and 441.07% for MB, RR, CV, and FG dye, respectively. Further, the adsorption process mainly followed a pseudo-second-order kinetic model, and the thermodynamic studies revealed the exothermic nature of adsorption for RR and FG dye while endothermic for MB and CV dye, respectively with varying from - 1.68 to - 6.12kJ/mol indicating the spontaneity of the process. Importantly, the efficacy of the composite was evaluated for the treatment of textile industry effluent highlighting its potential as an adsorbent for wastewater treatment.

Sustainability, performance, and production perspectives of waste-derived functional carbon nanomaterials towards a sustainable environment: A review

The survival of humanity is severely threatened by the massive accumulation of waste in the ecosystem. One plausible solution for the management and upcycling of waste is conversing waste at the molecular level and deriving carbon-based nanomaterial. The field of carbon nanomaterials with distinctive properties, such as exceptionally large surface areas, good thermal and chemical stability, and improved propagation of charge carriers, remains a significant area of research. The study demonstrates recent developments in high-value carbon-based photocatalysts synthesis from various waste precursors, including zoonotic, phytogenic, polyolefinic, electronic, and biomedical, highlighting the progression as photocatalysts and adsorbents for wastewater treatment and water splitting applications. This review highpoints the benefits of using waste as a precursor to support sustainability and circular economy and the risks associated with their use. Finally, we support that a sustainable society will eventually be realized by exploring present obstacles and potential steps for creating superior carbon-based nanomaterials in the future.

The Use of Sawdust at different thickness as low cost adsorbent in wastewater treatment

The Use of Sawdust at different thickness as low cost adsorbent in wastewater treatment

A green cross-linking method for the preparation of renewable three-dimensional graphene sponges for efficient adsorption of Congo red dye

Graphene-based materials possess significant potential for the treatment of dye wastewater due to their exceptional adsorption properties toward stubborn pollutants. However, their utilization is hindered by high preparation costs, low yields, environmental pollution during synthesis, and challenges in regenerating the adsorbent. This study proposes a novel approach to address these limitations by developing nitrogen-doped three-dimensional (3D) polyvinyl alcohol cross-linked graphene sponges (N-PGA) using a cross-linking method with ammonium carbonate. This method offers a relatively mild and environmentally friendly approach. Ammonium carbonate serves as both a reducing and modifying agent, facilitating the formation of the intrinsic structure of N-PGA and acting as a nitrogen source. Meanwhile, polyvinyl alcohol (PVA) is utilized as the cross-linking agent. The results demonstrate that N-PGA exhibits a favorable internal 3D hierarchical porous structure and possesses robust mechanical properties. The measured specific surface area (BET) of N-PGA was as high as 406.538 m2·g–1, which was favorable for its efficient adsorption of Congo red dye molecules. At an initial concentration of 50 mg·L–1, N-PGA achieved an impressive removal rate of 89.6% and an adsorption capacity of 112 mg·g–1 for Congo red (CR) dye. Furthermore, it retained 79% of its initial adsorption capacity after 10 cycles, demonstrating excellent regeneration performance. In summary, the synthesized N-PGA displays remarkable efficacy in the adsorption of CR dye in wastewater, opening up new possibilities for utilizing 3D porous graphene nanomaterials as efficient adsorbents in wastewater treatment.

Enhanced methylene blue adsorption by double alkali activation of highly porous glass microspheres prepared from waste glass

The remediation of water from organic pollutants, such as dyes and related compounds and the reuse of discarded glasses, represents fundamental challenges in highly industrialized countries. Porous glass microspheres have been proposed as efficient adsorbents in wastewater treatment, but their real application is problematic, especially from the perspective of their reuse and recycling. For the first time, the present paper describes the process of preparation and use of highly porous bodies with a specific surface area of nearly 20 m2/g fabricated from alkali activated glass microspheres and applicable for the removal of methylene blue as a model organic dye from wastewater. Alkali activation is applied both as an intermediate step (using 9 M KOH) for the conversion of waste glass into porous microspheres by flame spheroidization process, and as a final step (using 2.5 M NaOH), facilitating low temperature consolidation of the microspheres, and their transformation into porous structures. The experimental adsorption capacity of porous glass microspheres pellet was 122 mg/g. The high correlation coefficient indicates the applicability of Langmuir isotherm adsorption model.

Sustainable oil palm trunk fibre based activated carbon for the adsorption of methylene blue

Activated carbon (AC) is becoming the limelight due to its widespread application as an adsorbent for wastewater treatment, gases, and catalysis. However, its high consumption and price have drawn more attention to the sustainable use of natural resources as precursor for AC production. This study focuses on synthesising AC from two types of oil palm trunk (OPT) fibres, a significant agricultural waste products produced by Malaysia's thriving palm oil industries. The BET surface area of about 2057.9 m2 g−1 was achieved by chemical activation with phosphoric acid (H3PO4). The efficiency of the synthesised AC was critically analysed based on the adsorption experiments with methylene blue (MB) by varying several parameters (dosage of adsorbent, pH, initial dye concentration, and temperature of the solution) to elucidate the adsorption mechanism(s). A maximum adsorption capacity of 320.4 mg g−1 at 50 °C was achieved, and the Temkin (r2 = 0.98, 0.95, 0.95) and Langmuir (r2 = 0.94, 0.93, 0.95) isotherm models fitted the adsorption process better than the Freundlich (r2 = 0.95, 0.90, 0.86) model. Besides, the pseudo-second-order model (r2 > 0.90) best described the adsorption process, favouring chemisorption over physisorption. Thermodynamics showed MB adsorption on AC was spontaneous except at the highest dye concentration. It was exothermic at lower dye concentrations (50 and 100 mg L−1) and endothermic at higher ones (300, 500, and 700 mg L−1). In a nutshell, this study reveals that OPT fibre is a promising precursor for synthesising highly porous AC for the adsorption of MB dye.

Nanostructured Cellulose-Based Aerogels: Influence of Chemical/Mechanical Cascade Processes on Quality Index for Benchmarking Dye Pollutant Adsorbents in Wastewater Treatment.

(1) Background: Nanostructured cellulose has emerged as an efficient bio-adsorbent aerogel material, offering biocompatibility and renewable sourcing advantages. This study focuses on isolating (ligno)cellulose nanofibers ((L)CNFs) from barley straw and producing aerogels to develop sustainable and highly efficient decontamination systems. (2) Methods: (Ligno)cellulose pulp has been isolated from barley straw through a pulping process, and was subsequently deconstructed into nanofibers employing various pre-treatment methods (TEMPO-mediated oxidation process or PFI beater mechanical treatment) followed by the high-pressure homogenization (HPH) process. (3) Results: The aerogels made by (L)CNFs, with a higher crystallinity degree, larger aspect ratio, lower shrinkage rate, and higher Young's modulus than cellulose aerogels, successfully adsorb and remove organic dye pollutants from wastewater. (L)CNF-based aerogels, with a quality index (determined using four characterization parameters) above 70%, exhibited outstanding contaminant removal capacity over 80%. The high specific surface area of nanocellulose isolated using the TEMPO oxidation process significantly enhanced the affinity and interactions between hydroxyl and carboxyl groups of nanofibers and cationic groups of contaminants. The efficacy in adsorbing cationic dyes in wastewater onto the aerogels was verified by the Langmuir adsorption isotherm model. (4) Conclusions: This study offers insights into designing and applying advanced (L)CNF-based aerogels as efficient wastewater decontamination and environmental remediation platforms.

Progress in agricultural waste derived biochar as adsorbents for wastewater treatment

The wastewater generated from diverse human activities needs to be treated, restore, and reused. Researchers have moved from the deployment of synthetic absorbents to manufacturing adsorbents from waste biomass for the elimination of contaminants from wastewater. The deployment of biochar constructed from agricultural waste has elicited significant devotion due to its ready availability, accessibility, low cost, ease of preparation, and environmental sustainability. This review presents developments in the utilization of biochar obtained from agricultural waste for the remediation of domestic wastewater, industrial wastewater, agricultural wastewater, and stormwater. Discussions on the classification, composition, and characteristics of agricultural waste, techniques for biochar production, and characteristics of wastewater as well as the outcomes of the deployment of biochar in the decontamination of wastewater were highlighted. The study concludes that, notwithstanding the identified environmental, social, economic, and infrastructural challenges, biochar constructed from agricultural waste is an effective, efficient, easy to use, and eco-friendly adsorbent for the decontamination of wastewater. Agricultural waste-derived biochar removes contaminants from wastewater and safeguards aquatic ecosystem and contributes to availability of safe water. Future research directions on innovative and more effective avenues for the application of biochar developed from agricultural waste for wastewater treatment are suggested. The outcome of this review will stimulate renewed interests in using readily available and eco-friendly materials in wastewater remediation.