Adsorbent For Removal Of Pollutants Research Articles

Enhanced phosphorus adsorption performance of ZnAl-LDO by fluorine‑chlorine co-doping and synergistic mechanism exploration

Layered double hydroxides (LDHs) and their calcined products layered double oxides (LDOs) are widely used as adsorbents for pollutant removal. Their adsorption performance are significantly influenced by intercalated ions, while previous studies primarily focusing on the impact of individual ions. For the first time, this paper reports the mechanism of the synergistic enhancement of phosphate adsorption properties of LDO by bicomponent interlayer ions. The ZnAl-LDO by fluorine‑chlorine co-doping (F, Cl-ZnAl-LDO) exhibits excellent adsorption capacity of 158.9 mgP/g, surpassing that of single-component intercalation Cl-ZnAl-LDO and F-ZnAl-LDO, as well as most LDH-based adsorbents. Further research and density functional theory calculations indicate the differential adsorption enhancement mechanism of the interlayer ions. Chlorine functions as the exchanged anion, whereas fluorine facilitates the complete replacement of chloride ions and hydroxyl groups by phosphate. This finding highlights the potential of utilizing the synergistic effects between different interlayer ions to design and synthesize advanced phosphate adsorbent materials.

Dihydrotetrazine-Functionalized Zirconium-Based Metal-Organic Frameworks for High-Capacity Oil Denitrogenation.

High structural stability, dual organic-inorganic nature, and tunability in chemical functionality are promising characteristics of zirconium-based metal-organic frameworks (Zr-MOFs). These properties assist Zr-MOFs in extending their applications in various fields, especially adsorptive removal of pollutants. In this work, two well-known Zr-MOFs (UiO-66(Zr) and MIL-140(Zr) with the formula Zr6O4(OH)4(BDC)6, H2BDC is benzene 1,4-dicarboxylic acid) were synthesized and decorated with a dihydrotetrazine functional group through postsynthesis linker exchange (PSLE). Two dihydrotetrazine (DHTZ)-functionalized frameworks, UiO-66(Zr)-DHTZ and MIL-140(Zr)-DHTZ, were applied for the removal of quinoline (Qui) and indole (Ind) from the model oil. The results of adsorption experiments at room temperature display that these functionalized Zr-MOFs have significantly improved removal capacities for Qui (875% for UiO-66(Zr)-DHTZ and 303% for MIL-140(Zr)-DHTZ) and Ind (722% for UiO-66(Zr)-DHTZ and 257% for MIL-140(Zr)-DHTZ). Mechanistic studies based on X-ray photoelectron (XPS) and Fourier-transform infrared (FT-IR) spectroscopies reveal that there is a specific kind of host-guest interaction between dihydrotetrazine and nitrogen-containing compounds (NCCs). UiO-66(Zr)-DHTZ adsorbs 1426 mg·g-1 Qui and 1176 mg·g-1 Ind, while MIL-140(Zr)-DHTZ adsorbs 619 mg·g-1 Qui and 511 mg·g-1 Ind. The lower adsorption capacities of MIL-140(Zr)-DHTZ compared to UiO-66(Zr)-DHTZ are related to its lower surface area (783 m2·g-1 versus 330 m2·g-1). The recyclability of the frameworks goes up to five cycles without any significant decrease in the removal capacity. These results indicate that dihydrotetrazine-functionalized Zr-MOFs are highly stable platforms with superior adsorption capacity compared to basic and neutral NCCs.

COF-derived porous nitrogen-doped carbon for removal of emerging organic contaminants and efficient uranium extraction from seawater

The development of adsorbents for efficient and highly selective seawater extraction of uranium was instrumental in fostering sustainable progress in energy and addressing the prevailing energy crisis. However, the complex background composition of the marine environment, including radionuclides, organic pollutants, and a large number of co-existing heavy metal ions, were non-negligible obstacles to the extraction of uranium from seawater. The present investigation successfully employed a self-templated approach to synthesize porous nitrogen-doped carbon (PNC) derived from COF, which exhibited tremendous potential as an adsorbent for pollutant removal in environmental treatment. LZU1@PNC not only retained the structural features of the original COF-LZU1, but also overcame the acid-base instability problem commonly found in COFs. Subsequently, the removal process of two typical water pollutants on the material was investigated using 2,4-DCP and [UO2(CO3)3]4-. The results demonstrated that LZU1@PNC exhibited superior removal performance for the target pollutants compared to COF-LZU1, owing to its larger specific surface area and abundant defect structure. After six desorption-regeneration cycles, LZU1@PNC still maintained a high removal rate of the target contaminants, demonstrating the stability of this material and its excellent recyclability. In addition, based on various characterization techniques, the removal mechanism of 2,4-DCP was presumed to be mainly electrostatic attraction, hydrogen bonding, and π-π stacking interactions. Conversely, the elimination process of [UO2(CO3)3]4- predominantly relied on surface complexation phenomena. The present investigation provided new perspectives and stimulated a broader study of other COF-derived carbon materials and their modifications as adsorbents for uranium extraction from seawater and other applications.

LaxNiy Mn2-(x+y)O3/g-C3N4 composite: A multifunctional material for photocatalytic and adsorptive removal of pollutants with statistical evaluation

The disposal of tons of organic chemicals annually in water resources is an alarming threat to the environment. Among the various remediation techniques, the combination of adsorption and degradation is a highly effective and economical strategy for eliminating these contaminants. In this study, a novel LaxNiyMn2-(x+y)O3/g-C3N4 composite [x,y = (0.00,0.00), (0.03,0.06), (0.06,0.03), (0.045,0.045)] is synthesized by a low-temperature and cost-efficient sol-gel auto-combustion method to address this issue. Field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) were used to characterize the morphology and crystal structure of the composite, respectively. The optical properties of the composite were investigated by a UV–visible spectrophotometer. The photocatalytic performance of the prepared samples was evaluated against crystal violet and 4-nitrophenol under solar irradiation. The doped composite La0.06Ni0.03Mn1.91O3/g-C3N4 exhibited superior degradation efficiency of 87.54 % for crystal violet in 60 min, compared to 56.2 % for the undoped composite. The same composite also achieved 78 % reduction of 4-nitrophenol without any external reducing agent. Furthermore, adsorption isotherms models and statistical analysis were applied to the composite to elucidate the adsorption mechanism and the optimal conditions. The results demonstrated that the composite is an excellent candidate for environmental remediation due to its remarkable degradation and adsorption capabilities against organic pollutants.

Pore-networked membrane using linked metal-organic polyhedra for trace-level pollutant removal and detection in environmental water

The wide presence of pharmaceuticals and personal care products (PPCPs) in water is a major pollution concern even at the part per billion level, which urges their detection and removal. Current research emphasizes the use of microporous materials as adsorbents for pollutant removal but demonstrates the performance at a higher concentration than realistic environmental water due to the absence of efficient detection methods that can be coupled with the removal process. Here we report a pore-networked membrane (PNM) that can simultaneously remove and detect targeted trace-level PPCPs. These PNMs are designed by interconnecting adsorbents within polymer matrices, forming continuous, tunable porous networks that are accessible for PPCPs, thereby offering high selectivity and adsorption capacity. Evaluations across water samples containing 13 pollutants demonstrate the capability of PNMs to selectively adsorb PPCPs for removal and subsequently release them into analysis solution for detection, positioning their promising use in real water treatment workflow.

Changes in the structure of red mud and black nickel mud after activation

This paper deals with the evaluation of the structure of selected hazardous wastes from the production of metals, namely waste from the production of aluminium - red mud and waste from the production of nickel - black nickel mud. In environmental applications, red mud and black nickel mud are likely to be used after activation. The samples were activated using hydrochloric acid to study the structure properties before and after the treatment. Both of these wastes have suitable adsorption and catalytic properties that could be positively affected by the activation of their surfaces. The morphology of the samples was documented by scanning electron microscope, phase analysis was performed using diffraction techniques, and the content of elements was determined by EDX analysis. Also, FTIR analysis of the samples was performed. Activation increases the specific surface area of samples, which is beneficial in many environmental applications, such as in the adsorptive removal of pollutants. Treatment of samples changes the surface properties of the adsorbent, such as electrostatic, hydrophobic, and hydrophilic. The activation creates a new surface structure and thus affects its properties. EDX analysis confirmed the high content of Fe, Al, Si and Ti, which are responsible for good adsorption and catalytic properties. X-ray diffractograms have shown only slight changes in the structure of wastes after activation. The results of SEM confirmed the changes in the surface structure and the creation of new active centres necessary for the successful adsorption process. The FTIR analysis determined the changes in the structure of the samples mainly due to the thermal degradation of C=O and O-Si-O bonds.

Synthesis of Ag-HKUST-1 composites and adsorption performance of neutral red dye

HKSUT-1 is often used as an adsorbent because of its excellent adsorption properties. In this study, Ag+ was impregnated into the HKSUT-1 precursor solution using the impregnation method, with sodium borohydride (NaBH4) serving as the reducing agent. This was done to examine the removal efficiency of NR dye. The Ag-HKSUT-1 composites were prepared by varying the additions of AgNO3 and NaBH4. The morphology and structure of the Ag-HKSUT-1 composites were characterized by TG, FT-IR, BET and TEM. The adsorption performance of AH1 for neutral red dye in wastewater was investigated. The adsorption process was described by the Langmuir model and the pseudo-second-order kinetic model. The adsorption capacity of AH1 for NR dye at 298 K was calculated to be 64.59 mg/g, indicating that Ag-HKUST-1 effectively adsorbed NR dye. The adsorption process is driven by a chemisorption mechanism, where intermolecular forces between Ag-HKUST-1 and NR, electrostatic interactions, and π-π conjugation between benzene rings play key roles. The results enhance our understanding of the surface interactions between Ag-HKUST-1 and NR dyes and broaden the application of HKUST-1 as an adsorbent for pollutant removal in water.

Highly enhanced chloramphenicol adsorption performance of MIL-53-NH2(Al)-derived porous carbons modified with tannic acid

The worldwide demand for antibiotics has experienced a notable surge, propelled by the repercussions of the COVID-19 pandemic and advancements in the global healthcare sector. A prominent challenge confronting humanity is the unregulated release of antibiotic-laden wastewater into the environment, posing significant threats to public health. The adoption of affordable carbon-based adsorbents emerges as a promising strategy for mitigating the contamination of antibiotic wastewater. Here, we report the synthesis of novel porous carbons (MPC) through a direct pyrolysis of MIL-53-NH2(Al) and tannic acid (TANA) under N2 atmosphere at 800 °C for 4 h. The effect of TANA amount ratios (0%–20%, wt wt−1) on porous carbon structure and adsorption performance was investigated. Results showed that TANA modification resulted in decreased surface area (1,600 m2 g−1–949 m2 g−1) and pore volume (2.3 cm3 g−1–1.7 cm3 g−1), but supplied hydroxyl functional groups. Adsorption kinetic, intraparticle diffusion, and isotherm were examined, indicating the best fit of Elovich and Langmuir models. 10%-TANA-MPC obtained an ultrahigh adsorption capacity of 564.4 mg g−1, which was approximately 2.1 times higher than that of unmodified porous carbon. 10%-TANA-MPC could be easily recycled up to 5 times, and after reuse, this adsorbent still remained highly stable in morphology and surface area. The contribution of H bonding, pore-filling, electrostatic and π–π interactions to chloramphenicol adsorption was clarified. It is recommended that TANA-modified MIL-53-NH2(Al)-derived porous carbons act as a potential adsorbent for removal of pollutants effectively.

Metal-Organic framework derived vulcanized functional materials for ultra-efficient treatment of Hg(Ⅱ) ions in water

Metal-organic frameworks (MOFs) and their derivatives have unparalleled potential in removing heavy metal ions from water. Herein, the synthesis and adsorption performance of porous materials derived from MOF derived (Sulfur@MOF) are described. Sulfur@MOF, which was prepared via a simple vulcanisation method, exhibited increased affinity for Hg(Ⅱ) ions owing to the successful introduction of sulfur. The adsorption capacity of Hg(Ⅱ) ions was studied by measuring the adsorption isotherms, adsorption kinetics and adsorption thermodynamics. Sulfur@MOF exhibited extremely high selectivity for Hg(Ⅱ) ions and could efficiently (99.9 %) capture Hg(Ⅱ) ions with an adsorption capacity of 1.2 g/g (ca. 120 min), reducing reducing pollutants with different concentrations from wastewater to drinking water standards. Moreover, Sulfur@MOF showed good reusability, with the removal rate after six cycles being greater than 95 %. Owing to its ultra-efficient removal ability and high adsorption capacity for Hg(Ⅱ) ions and good recyclability, Sulfur@MOF exhibits good application prospects as an adsorbent for pollutant removal.

Efficiency of engineered/modified biochars-based adsorbents for removal of pollutants from aquatic environment: A critical review

<p>Biochar shows substantial potential to contribute as a globally applicable adsorbent to decontaminate the water system due to the ample availability of feedstocks and valuable physio-chemical surface properties. This review aims to highlight the modification technologies of biochar, the alteration of characteristics after modification, and the eliminating of organic, inorganic, antibiotics and other pollutants from water systems by modified biochar. Alkali-acid modified and metal-loaded biochar possesses the superior surface functionality; these modifications are greatly favorable for improving the removal of different pollutants from water systems. Acidic- alkaline and metal treatment provides more diverse functional groups on biochar surfaces e.g. produces ample oxygenated functional groups, improve the surface attributes, generates high ratios of surface aromaticity and N/C, these changes provide the more adsorption sites and increase the removal of pollutants. This review also demonstrates the existing problems and future research direction related to modified biochars by acidic and alkaline agents as well as metal loaded composite in the remediation of the pollutants.</p>

Enhanced catalytic oxidation via nano Cu0.5Mg0.5Fe2O4 embedded in CNTs for adsorption–reduction of hexavalent chromium

AbstractA catalyst consisting of Cu0.5Mg0.5Fe2O4 (CMF) supported on carbon nanotubes (CNTs) which exhibits great potential as an adsorbent for treating Cr(VI)‐contaminated wastewater has been successfully prepared. The ferrite possesses excellent magnetic properties, while CNTs have the advantage of a large surface area. This composite material not only prevents the aggregation of magnetic materials and enhances the exposure of active sites but also effectively solves the recycling problem of CNTs. Our results show that the adsorption capacity of Cu0.5Mg0.5Fe2O4–carbon nanotubes (CMF‐CNTs) for Cr(VI) wastewater (45.60 mg/g) is 1.49 times higher than that of Cu0.5Mg0.5Fe2O4 (30.48 mg/g). Compared to a single catalyst, CMF‐CNTs not only improve the dispersibility of magnetic materials but also exhibit synergistic effects between the composite materials, enhancing the chemical adsorption capacity. After five consecutive adsorption and desorption experiments, the adsorption capacity of CMF‐CNTs remains at 88% of its initial value. Furthermore, the study of the catalyst before and after adsorption by XPS reveals that the valence state transition of Fe3+/Fe2+ and Cu2+/Cu+ plays a crucial role in the adsorption process. The results of this study demonstrate the potential of using waste materials for effective wastewater treatment and provide insights into the development of new adsorbents for pollutant removal.

Metal-organic framework-derived LaFeO3@C: An adsorbent for removing organic dyes from water

Metal-Organic Frameworks (MOFs) and MOF-derived materials are emerging as a potential candidate in the field of adsorption owing to their vital properties of high surface area, tunable porosity and diverse functionalities. However, the instability of MOFs in harsh environmental conditions prompted to produce more stable forms of MOF-derived materials for adsorption applications. Carbonization of MOFs is becoming an efficient method to prepare stable metal oxide-carbon hybrids as adsorbents for pollutant removal. This study presents the first-time report on utilizing MIL-100(Fe)-derived mesoporous LaFeO3@C nanocomposites for the effective adsorption removal of methyl orange (MO) and sulforhodamine B (SRB). The nanocomposites having different surface chemistry and textural properties are formed from MOF-gel precursor by varying the calcination temperature in the argon atmosphere. The LaFeO3 nanoparticles in the nanocomposites crystallized into the orthorhombic structure, which is confirmed from the XRD, Micro-Raman and FTIR analysis. The material obtained at 700 °C (LFO@C-700) exhibited higher removal efficiency of 99% and 97.1% towards SRB and MO, respectively. The chemisorption is identified as the main rate-limiting step in adsorption and the isotherm follows the Langmuir model suggesting the monolayer coverage of the adsorbates. The successful elimination of dye contaminants from real water samples and industrial effluents by LFO@C-700 indicates the practical utility of this adsorbent material. Several key chemical interactions, including H-bonding, electrostatic interactions, π-π and cation-π interactions promote the adsorption process. Moreover, the LFO@C-700 nanocomposite shows reusability with sustainable adsorption for repeated experiment cycles, suggesting this adsorbent's cost-effective use in practical applications.

Glycerol-based H3PO4-activated carbon as a versatile adsorbent for removal of pollutants from wastewater: A novel synthesis protocol

Aiming at revaluing oversupplied glycerol as a result of biodiesel production, this approach introduces an authentic synthesis protocol for producing glycerol-based activated carbons holding suitable textural/surface properties for an efficient application in the methylene blue and Pb2+ adsorption processes. Typically, glycerol and phosphoric acid were submitted to a polycondensation reaction in order to insert manipulable fractions of C-O-P bridge bonds throughout the whole polymer chain in the form of mono, di and triesters before the traditional carbonization and activation steps. The physicochemical and surface chemistry properties of the ACPs were characterized by means of N2 adsorption/desorption isotherms, thermal analysis, elemental analysis, surface functional groups titration and pHpzc, X-rays diffraction, FTIR spectroscopy and scanning electron microscopy. Indeed, such strategy gave rise to a set of micro/mesoporous activated carbons (ACP) with surface area of up to 1056 m2/g and total acidity, constituted by thermally insensitive carbonyls-/phosphorus-containing functional groups, ranging from 1.63 to 2.32 mmol g−1. Adsorptive features of the obtained series of activated carbons were validated in the methylene blue and Pb2+ removal processes reaching out adsorption capacity of up to 543.3 and 26.5 mg g−1 at 298 K, respectively. Additionally, after confronting experimental data with several isothermal and kinetic theoretical models, it was demonstrated that the adsorption mechanism of both pollutants onto the ACPs is driven by chemisorption up to the monolayer coverage. The thermodynamic study indicated spontaneity of the adsorption processes and suggested a relation between the textural properties and surface functionalities of the ACPs with the enthalpic nature of the adsorbent-adsorbate interactions.

Leaching of metals from red mud and toxicity in human cells in vitro

Toxicity of red mud, a waste from alumina production, was studied using human breast cancer MCF-7 cells. Culture medium was prepared by mixing water for 3 days with the red mud and removing solid particles afterwards (red mud water). Culture for 48 h of the cells in this medium in neutral pH decreased the cell viability, as analyzed by the MTT-test, and increased the formation of reactive oxygen species. Thus, neutralization does not eliminate the toxicity of red mud. In preliminary experiments, a combined effect of five metals (Cr, Li, V, Al, As) increased the formation of ROS (reactive oxygen species) statistically significantly. Each element separately did not have a similar effect. In environmental applications, red mud is likely to be used after activation. In this work, the red mud was activated using hydrochloric acid to study the physical and chemical properties before and after the treatment. Activation increased the specific surface area of red mud from 16 m2 g−1 to 148 m2 g−1, which is beneficial in many environmental applications such as in the adsorptive removal of pollutants. After activation, leaching of some elements from the red mud decreased (e.g. Al from 38.0 to 0.56 mg L−1, As from 21.0 to 2.1 μg L−1, V from 172.0 to 29.8 μg L−1) while some increased (e.g. Li from 0.04 to 2.81 mg L−1, Cr from 0.35 to 3.23 mg L−1).

Porous organic polymers for superefficient removal of pollutants from water: Design, synthesis and adsorption performance

Environmental pollution and energy shortage are key problems restricting human and social development. Finding a way to effectively adsorb organic pollutants in wastewater is of great significance for environmental protection. Here, we reasonably design and prepare three novel porous organic polymers with different ratios m-terphenyl (POP-Ts) by Friedel-Crafts alkylation as excellent adsorbents, named POP-T (1:1), POP-T (1:1.5) and POP-T (1:2), respectively. Notably, the proportion of m-terphenyl and biphenyl dichlorobenzyl was optimized for the first time to obtain POPs adsorbents for removal of pollutants from water. Specially, the adsorption experiments showed that POP-T (1:1.5) has excellent adsorption performance of rhodamine B (RhB), methylene blue (MB) and diclofenac (DCF), and the maximum adsorption of POP-T (1:1.5) is 1414.4 mg/g, 1256.6 mg/g and 1028.9 mg/g, respectively. The kinetic data and isothermal data were well fit with the pseudo 2nd order model and Langmuir model, respectively. Moreover, all POP-Ts exhibit excellent stability and the adsorption efficiency is still over 90% after four cycles. Overall, the superefficient adsorption performance is attributed to the hydrophobicity property, large specific surface area (1416 m2/g) and porosity of the POP-T (1:1.5) material.

Valorization of sugarcane bagasse for sugar extraction and residue as an adsorbent for pollutant removal.

Following juice crushing for sugar or bioethanol production from sugarcane, bagasse (SCB) is generated as the main lignocellulosic by-product. This study utilized SCB generated by a hydraulic press as feedstock to evaluate sugar extraction as well as adsorption potential. Total soluble sugar (sucrose, glucose, and fructose) of 0.4 g/g SCB was recovered with H2O extraction in this case. Insoluble sugar, that is, cellulose in SCB, was further hydrolyzed into glucose (2%–31%) with cellulase enzyme, generating a new bagasse residue (SCBE). Persulfate pretreatment of SCB slightly enhanced saccharification. Both SCB and SCBE showed great potential as adsorbents with 98% of methylene blue (MB) removed by SCB or SCBE and 75% of Cu2+ by SCBE and 80% by SCB in 60 min. The maximum adsorption amount (q m) was 85.8 mg/g (MB by SCB), 77.5 mg/g (MB by SCBE), 3.4 mg/g (Cu2+ by SCB), and 1.2 mg/g (Cu2+ by SCBE). The thermodynamics indicated that the adsorption process is spontaneous, endothermic, and more random in nature. The experimental results offer an alternative to better reutilize SCB.

The effect of persistent free radicals in sludge derived biochar on p-chlorophenol removal

Sewage sludge pyrolysis can effectively dispose of sludge and obtain sludge-derived biochar (SDBC) as an adsorbent for pollutant removal. Recently, persistent free radicals (PFRs), which have also been detected in many types of biochar, have attracted considerable attention for organic pollutant degradation. Sludge collected from a sewage treatment plant was pyrolyzed into SDBC, which contained a large amount of PFRs, and the resulting SDBC was then applied for the removal of p-chlorophenol. An SDBC dosage of 5 g L−1 was applied for treating 5 mg L−1 of p-chlorophenol; the highest removal efficiency of 90% was achieved at pH 3, and 22% of the initial p-chlorophenol was degraded by the SDBC. Hydroxyl free radicals were observed and contributed to the degradation of p-chlorophenol. The spent SDBC was reused five times after regeneration through the desorption of adsorbed p-chlorophenol. The p-chlorophenol removal efficiency remained constant, but the degradation decreased with increasing reuse cycles, suggesting that the p-chlorophenol degradation efficiency was positively correlated with the intensity of PFRs on SDBC. Further modification of the SDBC sample in HNO3 or NaOH increased the amount of PFRs, and consequently, the degradation of p-chlorophenol under low oxygen conditions, further confirming the crucial role of PFRs in p-chlorophenol degradation. This study provides insights into the application of SDBC, a promising material, for contaminant abatement.

A Review on Bamboo as an Adsorbent for Removal of Pollutants for Wastewater Treatment

Water and wastewater treatment are very important for obtaining clean and sanitary water as well as protecting the environment from toxic pollutants. Not only enriched with cellulose and carbon but the abundant resources of bamboo also make it suitable to be utilized as an adsorbent. With the right processing technologies and improvements, the potential of bamboo is unlimited. This study review provides knowledge on the use of bamboo-based adsorbents for the removal of contaminants and pollutants in wastewater in the form of activated carbon, biochar, and aerogel. This review highlighted bamboo utilization and its relevance as an adsorbent for wastewater treatment. The technologies for the processing and improvement of bamboo as well as the performance of the bamboo-based adsorbents are also discussed in this study. The adsorption capacity of bamboo has shown improvement with modification and good adsorption capacity achieved with some of the adsorbent being able to be recycled and reused.

Adsorptive removal of pollutants from water using magnesium ferrite nanoadsorbent: a promising future material for water purification.

Nanoadsorbents having large specific surface area, high pore volume with tunable pore size, affordability and easy magnetic separation gained much popularity in recent time. Iron-based nanoadsorbents showed higher adsorption capacity for different pollutant removal from water among other periodic elements. Spinel ferrite nanomaterials among iron-bearing adsorbent class performed better than single iron oxide and hydroxides due to their large surface area, mesoporous pore, high pore volume and stability. This work aimed at focusing on water treatment using magnesium ferrite (MgFe2O4) nanomaterials. Synthesis routes, properties and pollutant adsorption were critically investigated to explore the performance of magnesium ferrite in water treatment. Structural and surface properties were greatly affected by the factors involved in different synthesis routes and iron and magnesium ratio. Complete removal of pollutants through adsorption was achieved using magnesium ferrite. Pollutant adsorption capacity of MgFe2O4 and its modified forms was found several folds higher than Fe2O3 and Fe3O4 nanomaterials. In addition, MgFe2O4 showed strong stability in water than other pure iron oxide and hydroxide. Modification with graphene oxide, activated carbon, biochar and silica was demonstrated to be beneficial for enhanced adsorption capacity. Complex formation was suggested as a dominant mechanism for pollutant adsorption. These nanomaterials could be a viable and competitive adsorbent for diverse pollutant removal from water.

Biochar and activated carbon derivatives of lignocellulosic fibers towards adsorptive removal of pollutants from aqueous systems: Critical study and future insight

The enormous growth of industries and the increased release of untreated effluents containing emerging pollutants are major problems that contaminate the water resources. Current efforts are oriented towards developing cost-effective, eco-friendly alternatives to remove a wide range of water pollutants. This paper provides critical insight on various lignocellulosic fibers used for colored and wastewater decontamination. The potential of various agricultural waste materials and their adsorptive capacity of pollutants compared to activated carbon was discussed. Furthermore, an outline of the mathematical modeling describing the kinetics, isotherms, the type of adsorption, and the significant factors influencing the adsorption process were reported. Also, a discussion of the new trends proposed for valorizing vegetable materials in wastewaters decontamination was pointed out. The proposed mechanism for the surface-based adsorption of pollutants onto the lignocellulosic fiber surface was discussed. The challenges and future scope of research on the surface-based removal of pollutants were also discussed.