Adsorption Kinetics Research Articles

Pd modified by Fe-Nx confined in N-doped carbon with hierarchical mesoporous structure for the highly efficient semi-hydrogenation of phenylacetylene

The removal of small amounts of phenylacetylene from styrene is a crucial step in the production of high-quality styrene feedstocks. In the presence of a large amount of styrene and a small amount of phenylacetylene, achieving and maintaining high selectivity of styrene remains a significant challenge. In this work, a catalyst denoted as Pd1.25-Fe-N-C/VC was designed and synthesized with remarkably low Pd loading (the actual Pd content was 0.96 wt%). The catalyst exhibited a satisfactory selectivity for styrene (>95 %) and maintained high selectivity levels (>90 %) in the semi-hydrogenation of phenylacetylene even with prolonged reaction time. Pd nanoparticles (NPs) were well distributed and securely anchored onto the Fe-N-C/VC support with a hierarchical mesoporous structure, which obtained from the pyrolysis of a hexagonal star-like Fe-doped zeolitic imidazolate framework with vitamin C surfactant (Fe-doped ZIF/VC). The remarkable catalytic properties may be partly ascribed to the effective synergy effect of the uniformly well-dispersed Fe-Nx (x represents the coordination number) with Pd active centers, which could modulate the adsorption kinetics of the reactant alkynes and alkenes and thus enhancing the selectivity towards styrene. Meanwhile, the hierarchical mesoporous structure is beneficial for the mass transfer, which can effectively promote the interactions between the reactants and active centers. Possible mechanism for the selective hydrogenation of phenylacetylene catalyzed by Pd1.25-Fe-N-C/VC was also illustrated. Moreover, the Pd1.25-Fe-N-C/VC catalyst exhibited sustained catalytic activity and selectivity even after four continuous cycle tests, showing notable reusability and stability. This work may offer a promising approach for creating highly efficient Pd-based catalysts with remarkably low Pd loading for phenylacetylene semi-hydrogenation.

A readily accessible quaternized cellulose filter paper with high permeability for IgG separation

Anion-exchange chromatography (AEC) is recognized as a highly effective approach for the purification of immunoglobulin G (IgG). This study introduces an innovative strategy that employs waste cellulose filter paper in the production of AEC media. A quaternized cellulose fiber membrane (CFM-QCS) was successfully fabricated that cellulose fibers were as a structural framework, glutaraldehyde (GA) as a crosslinking agent, and quaternary chitosan (QCS) as a modifying agent. Morphological and chemical characterization revealed that GA and QCS were uniformly crosslinked on the surface of the cellulose fibers, resulting in excellent mechanical properties in both dry and wet states. Benefiting from its 3D network scaffold structure, CFM-QCS demonstrated a high adsorption capacity for bovine serum albumin (BSA), with static and dynamic adsorption capacities of 605.15 mg/g and 88.63 mg/ml, respectively. After treated with extreme conditions and 10 cyclic adsorption and elution, the adsorption capacity of CFM-QCS remains almost unchanged, highlighting its excellent stability. Additionally, a CFM-QCS packed chromatography column exhibited high flux of 10.38 L/h at 0.1 MPa, which can efficiently separate IgG from a mixed solution in the presence of BSA and IgG by gravity-driven. This work presents a straightforward approach for preparing high-performance ion-exchange chromatography membranes for IgG separation.

Anthill clay activated Ocimum gratissimum extract for effective adsorption of methylene blue and chromium (VI) ion from wastewater: Insights into the adsorption isotherms, kinetics, thermodynamics, and mechanisms

The removal of methylene blue (MB) dye and hexavalent chromium (Cr(Vl)) ions from water bodies have necessitated the search for a promising adsorbent material with high adsorptive performance, facile operation, and economical. Here, a novel adsorbent was prepared by activating anthill clay (AC) with Ocimum gratissimum leaf extract (OG@AC) by ultrasonic strategy method to eliminate MB and Cr(Vl) from the aqueous environment; however, the activation strategy serves as an important factor that influenced the adsorptive performance towards MB and Cr(Vl). Furthermore, a high BET surface area of 120.48 m2/g was measured for OG@AC which is attributed majorly to the green activation strategy. The SEM micrograph of OG@AC was seen to have displayed a leaf-like plate formed by quartz and kaolin. In the batch experimental study, the MB and Cr(Vl) adsorption capacities towards OG@AC were determined to be 227.52 and 143.45 mg/g, respectively. Also, the adsorption kinetics and isotherms models results revealed that the adsorption process of OG@AC towards MB and Cr(Vl) was best described by pseudo-first-order and Freundlich models, suggesting that the adsorption process involves a multilayer physisorption. Moreso, thermodynamic results revealed the adsorption process is feasible, spontaneous, and endothermic in nature. The OG@AC exhibited an outstanding regeneration ability and stability towards MB and Cr(Vl) by maintaining a removal efficiency of 79.11 % and 81.20 % even at the tenth successive adsorption-desorption cycles. Overall, this research sheds more insight on how anthill clay is activated using a feasible design and green chemical (Ocimum gratissimum leaf extract) to enhance its adsorptive performance towards MB and Cr(Vl), which can broaden its wide application in the real world.

Preparation of new green poly (amino amide) based on cellulose nanoparticles for adsorption of Congo red and its adaptive neuro-fuzzy modeling

In this study, a novel green poly(amino amide) nanoparticle based on cellulose nanoparticles (Cell-PAMN) was developed for the efficient adsorption of Congo Red dye. Cellulose nanocrystals obtained from acid hydrolysis of cotton linter were functionalized via Oxa-Michael addition of acrylamide on their surface hydroxyl groups, followed by transamidation with ethylenediamine. The resulting nanoparticles were characterized using FT-IR spectroscopy, SEM, and X-ray diffraction techniques. The as-prepared Cell-PAMN exhibited considerably higher adsorption capacity compared to unmodified cellulose nanoparticles due to the presence of amino and amide functional groups. The adsorption kinetics and the effects of parameters such as contact time and initial dye concentration on the adsorption capacity were investigated. An adaptive Neuro-Fuzzy model was used to study the efficiency of dye removal, accurately predicted the adsorption behavior of Cell-PAMN. The kinetic study results showed that the adsorption process followed a pseudo-second-order kinetic model, with a maximum adsorption capacity of around 40 mg/g. The results demonstrated the potential of the synthesized material for the removal of Congo Red from aqueous solutions, highlighting its applicability in wastewater treatment. This research contributes to the development of sustainable and eco-friendly materials for environmental remediation applications.

Active sites regulation and adsorption performance of Al-pillared bentonite for the removal of lead from aqueous phase

Developing an environmentally friendly adsorbent with high adsorption capacity and economic benefits is crucial for the treatment of lead-contaminated wastewater. In this study, active clay (A-bent) and Al pillared acid-activated clay (A-AlPILC) were prepared using natural bentonite as the carrier via acidification and pillar-supported technology. The samples were characterized by X-ray diffraction (XRD), N2 adsorption-desorption experiments, Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray fluorescence spectrometer (XRF). The results showed that the amended clay exhibited an increase in specific surface area (SSA) from 39.37 m2/g to 175.28 m2/g and 245.42 m2/g compared to raw bentonite. The interlayer spacing and total pore volume rose respectively. The adsorption technique achieved an impressive removal rate of 90.6 % for Pb(II). Adsorption data were fitted by adsorption kinetics and adsorption isotherm model. Based on the response surface method (RSM), and analysis of variance (ANOVA) showed that the influence of these variables was significant. The simulation of lead ions showed that the acidic functional groups and ligands promote adsorption more than they inhibit it. Using the density function theory (DFT) calculation, the bentonite cycle model was established to demonstrate the interaction between bentonite and lead, with a binding energy of −0.369 eV. Similarly, the density and energy band structure of the state were computed to explore the mechanism of heavy metal adsorption by clay minerals.

Kinetic and isotherm adsorption studies of Zn (II) ions on hydroxyapatite nanoparticles: Linear and nonlinear analyses

Kinetic and isotherm adsorption studies of Zn (II) ions on hydroxyapatite nanoparticles: Linear and nonlinear analyses

Rational design of MoS2 nanoflowers-decorated carbon nanofibers with enhanced electronic transmission for boosting capacitive deionization

Capacitive deionization (CDI) has sparked considerable interest for its promising application in handling brackish water. Unfortunately, most traditional carbonaceous materials are still plagued by the limited desalination capacity and sluggish adsorption kinetics with the single adsorption mechanism and irrational pore structure. Herein, we developed a facile and affordable strategy to integrate electrospinning with hydrothermal method to fabricate MoS2 nanoflowers-decorated carbon nanofibers (MoS2/CNF) composite for boosting desalination performance. CNF not only serves as a supportive framework to inhibit the agglomeration of MoS2 nanosheets favoring the full contact with salt solutions, but also typically diminishes the charge transfer resistance of the composite. By taking advantage of the double layer adsorption of CNF and the hierarchically micro-mesoporous structure of MoS2 nanoflowers with large interlayer spacer for salt ions intercalation, the optimized sample MoS2/CNF-1 employed as a cathode for the asymmetric hybrid CDI cell showed an eminent capacity for desalination of 30.9 mg·g−1, an ultrafast rate for desalination of 3.7 mg·g−1·min−1, and an attractive circulation stability for desalination with the capacity reservation remaining at 94.8 % after 30 cycles in the solution of 500 mg·L−1 NaCl at 1.2 V. This research sheds fresh light on the evolution of advanced CDI electrode materials for practical utilization.

ZVI-biochar granules for reactive chlorinated solvent filters generated by high temperature pyrolysis of iron(III) amended biomass

Reactive filters may replace activated carbon filters for degradation of chlorinated solvents in contaminated waters. Reactive porous filter materials with high hydraulic conductivity may be in form of millimeter sized zero valent iron (ZVI)-biochar granules produced via carbothermal reduction. We screened ZVI-biochar materials produced under different synthesis conditions including different iron sources, nitrogen additives and supplementary organic substrates followed by testing adsorption and dechlorination kinetics. Diatomaceous earth was used as an inorganic host reference material. The optimal product from the screening was identified as beech charcoal amended with Fe(III) chloride and urea followed by tube furnace pyrolysis at 1000 °C for 2 h. The millimeter sized granules have a high porosity of 79 %. This material resulted in fast trichloroethylene (TCE, 100–600 µM) sorption and complete dechlorination with acetylene as the main product. It also showed a 5 to 8.5-fold higher degradation capacity than the diatomaceous earth reference system. Fitted pseudo first-order dechlorination rate constants (0.114–0.281 h−1) were comparable to rates reported for powdered ZVI-activated carbon materials. In reactions with high TCE concentrations, Fe(0) consumption for TCE reduction reached up to 93.3 % demonstrating its high selectivity. Reactions with ground material demonstrated that intraparticle diffusion pose minor limitation to dehalogenation rates in the highly porous granules. Further tests demonstrated that the material was further highly reactive to tetrachloroethylene (PCE), cis-1,2-dichloroethyene (cis-DCE) and vinyl chloride (VC). The ZVI-BC material addresses the dual challenges of achieving both high hydraulic conductivity and dehalogenation reactivity, offering a cost-efficient and sustainable option for filter material selection in the remediation of CEs using reactive filters or permeable reactive barriers.

Development and solution of the kinetics equation and adsorption isotherm for gold adsorption from cyanide solutions onto activated carbon

Development and solution of the kinetics equation and adsorption isotherm for gold adsorption from cyanide solutions onto activated carbon

Insights into the Effect of Crystal Facets and Sulfur Defects on the Product Selectivity of Various CdS Configurations for CO2 Photoreduction: A DFT Study

CO2 photoreduction into valuable hydrocarbons, such as CO, CH4, and C2H4, delivers a promising approach to address both environmental and energy challenges. Transition metal chalcogenides, particularly cadmium sulfide (CdS), have emerged as prominent candidates due to their tunable electronic properties and availability. This study delves into a comprehensive investigation of how CdS crystalline facets and sulfur-deficient surfaces modulate the product selectivity. Through employing density functional theory (DFT), we unravel the catalytic performance of various CdS crystal orientations and sulfur vacancy configurations. The results have shown that different CdS facets exhibit unique electronic characteristics and surface energetics, which influence the adsorption dynamics and reaction pathways. The introduction of sulfur vacancies further modulates the nature of active sites, leading to substantial shifts in product selectivity. A detailed investigation on the reaction mechanisms unveils that specific facets preferentially facilitate the formation of CO, while others are more conducive to the generation of hydrocarbons such as CH4 and C2H4, due to the variations in activation barriers and intermediate stabilities. These findings underscore the importance of crystal facet engineering and defect manipulation in tailoring catalyst performance thus providing valuable insights for the rational design of efficient and selective CO2 reduction metal catalysts.

A new explanation for the synergistic promoted mechanism of nitrate and nitrite anion species for the high performance MgO adsorbent

The mechanism of CO2 capture on the nitrate and nitrite anion species synergistic promoted MgO has been rarely studied and still not fully understood. Herein we report a systematic investigation on the CO2 adsorption performance of molten salts-promoted MgO adsorbent to deeply reveal the synergistic promoted mechanism of nitrate and nitrite. A series of MgO-based solid adsorbents were synthesized and applied for CO2 capture using NaNO2/KNO3 as promoters. The addition of mixed nitrate and nitrite promoters greatly enhances the adsorption capacity of MgO, exhibiting CO2 capture up to 10.25 mmol·g−1 under optimal conditions. The MgO-based adsorbent in the form of nanosheets has faster adsorption kinetics and better stability, and the possible reaction mechanism of MgO modified by nitrate and nitrite was proposed. Firstly, NO3– interacts with the lattice oxygen (O12-) of MgO to form NO2– and O22–. Secondly, Mg2+ interacts with the free NO2– to form [Mg···NO2]+ and further overcomes the energy barrier to generate [Mg2+···O2–] ion pairs. O22– is not stable and prone to side reaction. However, NO2– can be converted into O2–, and O2– is further generated to O22–, facilitating regeneration of NO3–. The introduction of molten salt can significantly reduce the reaction energy barrier, and the energy barrier required to generate [Mg2+···O2–] ion pairs is reduced from 6.86 eV to 3.50 eV. Adsorption kinetics studies reveal that the nano-flake MgO facilitates the full contact with the promoter and has faster reaction kinetics in the surface reaction control stage. These insights into the synergistic promoted mechanism of nitrate and nitrite anion species is expected to provide guidance for the further design of the high performance MgO-based CO2 adsorbent.

Carbonization of Invasive Plant Species—Novel Route for Removal of Active Pharmaceutical Ingredients via Adsorption

The development of efficient adsorbents for sustainable adsorption processes is required in environmental studies. Here, we propose using carbonized Ailanthus altissima leaves as a novel adsorbent, derived from invasive species that threaten biodiversity. Biochar was prepared by pyrolysis at 500 °C, activated with ZnCl2 and tested for the target adsorbates—active pharmaceutical ingredients (APIs). A range of characterization techniques were employed—FTIR, SEM, XPS and Raman spectroscopy—and the adsorption of representative APIs was analyzed. The adsorption kinetics revealed that the adsorbent reached equilibrium within a 3 h period. The adsorption capacities for the selected model substances ranged from 59 mg g−1 for atenolol to 112 mg g−1 for paracetamol, while the highest values were recorded for ketorolac and tetracycline at over 130 mg g−1. The excellent retention is ascribed to the developed surface area, the availability of oxygen surface functional groups and the aromatization of the biochar. The proposed biochar, which is obtained in a sustainable process, proves to be a highly efficient adsorbent for selected pharmaceuticals.

Study on the preparation of a novel acrylic modified magnetic chitosan adsorbent and the adsorption behavior on Ga (III)

In the current study, a novel acrylic modified magnetic chitosan adsorbent (M- AA −CTS) was prepared, and then characterized using SEM, FTIR, and XPS. The preparation conditions, adsorption conditions, adsorption kinetics and thermodynamics were also studied. FTIR results indicate that acrylic acid is grafted onto the amino groups of chitosan in the form of poly acrylic acid and the amino groups are also crosslinked with glutaraldehyde. For the preparation process, the removal efficiency of Ga (III) ions is higher when the amount of acrylic acid is 3 mL, the reaction temperature is 308 K, the crosslinking time is 80 min, and the amount of glutaraldehyde is 0.6 mL. During the adsorption process, the higher adsorption capacity of Ga (III) ions can be achieved under the condition of the initial concentration of Ga (III) ions 50 mg/L, the adsorbent dose 0.05 g, the oscillation temperature 308 K and pH 3. The study on the adsorption kinetic indicates that the adsorption follows the pseudo-second-order kinetic model. The study on isotherm adsorption and thermodynamic indicates that the adsorption isotherm fits the Langmuir isotherm model better and the saturated adsorption capacity of Ga (III) ions on M−CTS−AA can reach 183.09 mg/g. Study on desorption and regeneration shows that after four cycles of desorption and reuse, the regeneration rate decreased from the initial 91.47 % to 73.3 %.

Performance study of phenol sequestration from agricultural wastewater by chemical activated Montmorillonite

Agricultural by-products possess potential as cost-effective adsorbents for the remediation of phenolic contaminants in environmentally treated wastewater. This research focuses on the utilization of Algerian montmorillonite clay, specifically modified montmorillonite (Mo-5N), treated with 5N hydrochloric acid (HCl), compared to its untreated form (Mo-0N), for phenol sequestration from pesticide-laden waters. We employed various analytical techniques, such as chemical analysis, X-ray diffraction (XRD), and Fourier Transform Infrared (FTIR) spectroscopy, to characterize these adsorbents. The adsorption behavior was scrutinized under varying conditions, including pH, contact time, phenol concentration, and temperature. The maximum adsorption capacities achieved were 119.12 mg/g for Mo-5N and 100.89 mg/g for Mo-0N under optimal conditions of pH 5.72, a contact time of 120 minutes, and a temperature of 40°C. The kinetics of adsorption were best described by the pseudo-second-order and Elovich models, while the Freundlich isotherm model aptly described the equilibrium data. Thermodynamic analyses revealed that the phenol removal process using both forms of montmorillonite is spontaneous and endothermic. This study demonstrates the efficacy of Algerian montmorillonite clay in the removal of phenolic pesticides from agricultural wastewater.

Novel magnetic metal ferrite-mango starch composite for the removal of dyes in single and ternary dye mixtures from aqueous solutions: kinetic and thermodynamic studies

ABSTRACT Magnetic metal ferrites attached to biowastes are proven to be promising adsorbents for the removal of dyes from water. Magnetic composites with biopolymers are gaining interest in the field of treatment of wastewater because of their selective nature, recyclability, low cost and environmental compatibility. In this work, Zinc ferrite composite with starch, extracted from mango seed kernel (ZFNMS) was synthesised. Characterisation techniques, such as FTIR, XRD, FESEM, BET, TGA and pHzpc, were used for the structural analysis of ZFNMS. ZFNMS was used to remove Methylene blue, Crystal violet and Brilliant green dyes in single and multiple (ternary) dye systems. The kinetics of adsorption by ZFNMS revealed that pseudo-second-order of kinetics was most appropriate for this study. Maximum adsorption capacities using ZFNMS for CV, BG and MB dyes were 142.9, 101.2 and 105.8 mg/g, respectively. The values of adsorption energies using ZFNMS were 200.5, 494.3 and 183.6 KJ/mol for CV, BG and MB dyes, respectively. Thermodynamic data revealed the spontaneous nature of the adsorption of dyes by ZFNMS and it was found that chemical adsorption was taking place in the present study. Regeneration of the adsorbent was done for successive five cycles and showed significant results. Thus ZFNMS is an ideal adsorbent for cationic dyes removal from water.

Metal-modified biochars prepared from blue algae and their ability of adsorbing phosphates from water and utilization as soil amendment

The problem of blue algae accumulation can be alleviated by utilizing blue algae as biomass for resource utilization, which can remove excess phosphates from water to alleviate eutrophication. Herein, Magnesium (Mg) and/or lanthanum (La) were used to modify biochar via high-temperature slow pyrolysis with blue algae as the raw biomass. These modified biochars exhibited abundant carbon (18.0%-50.3%), oxygen content (17.4%-49.1%), along with a high specific surface area (82.26-233.80 m2/g). The surface of metal-modified biochar was enriched with hydroxyl and carboxyl groups and metal elements were efficiently incorporated into biochars. Adsorption kinetic and isotherm experiments were conducted under the optimal pyrolysis temperature of 600 °C, pH of 6.0, and adsorbent dosage of 2.0g/L. The adsorption kinetics studies by metal-modified biochars for phosphate fitted well pseudo-second-order model Redlich-Peterson isotherm model. Biochar modified by Mg and La exhibited the highest removal efficiency (97.8%) for phosphate at adsorption equilibrium. The adsorption mechanism involved the electrostatic interaction between hydroxylated metal oxides and negatively charged phosphate ions and the precipitation of phosphate ions through chemical reactions with metal oxides in the solution. After phosphate adsorption, the pristine and metal-modified biochars derived from blue algae were applied as the soil amendment. Biochar adsorbed phosphate apparently improved the germination rate of seeds facilitated the height, width, weight, and chlorophyll content of vegetable seedlings, and induced oxidative stress, which proved that the biochar recovered after adsorption was a high-quality soil amendment. This study provides a new approach for the treatment of phosphate wastewater and the algae application.

Synergistic degradation of toxic azo dyes using Mn-CuO@Biochar: An efficient adsorptive and photocatalytic approach for wastewater treatment

Congo red (CR) and Eriochrome Black T (EBT) is a toxic azo dye with a complex structure which represents a serious Ecotoxicological hazards for aquatic bodies. This research investigates the synergistic effects of Corn plants biochar and manganese (Mn)-composited copper oxide (CuO) in the adsorptive and photocatalytic degradation of toxic anionic dyes i.e. CR and EBT. The acquired materials were characterized by FTIR, XRD, SEM-EDX, XPS, TEM, BET, ZP, and pHZc test. The experiment demonstrated that Mn-CuO@BC composite exhibited a remarkable adsorption of ∼ 98 % and ∼ 95 % and photocatalytic degradation of 92 % and 88 % for CR and EBT respectively. It was further found that coupling of the H2O2 with Mn-CuO@BC enhances the photocatalytic efficiency of catalyst for CR and EBT i.e. upto ∼ 98 % and 96 % respectively possibly owing to the efficient ●OH radical. Adsorption kinetics followed a pseudo 2nd order model, indicating predominant chemisorption, and adsorption isotherms fit well with the Langmuir model. Further, toxicity degradation products of EBT were examined through ECOSAR indicated a reduced ecological impact. In general, this work highlight the dual functional advantages of the Mn-CuO@BC composite, providing an efficient and versatile approach for wastewater treatment involving complex dye pollutants.

Graphene oxide modified with magnesium hydroxide derived from dolomites for dyes adsorptions and supercapacitor

This research highlights the novelty of using dolomite as an Mg(OH)2 source for synthesizing GO/Mg(OH)2 nanocomposite, a dye adsorbent and supercapacitor material. So far, dolomite has only been conventionally used as fertilizer and building material. By utilizing dolomite as Mg(OH)2 raw materials, this nanocomposite shows high efficiency in removing methylene blue (MB) up to 97 % with adsorption kinetics following a pseudo-second-order model. At an optimal pH of 5, this material can be used repeatedly with satisfactory results. For supercapacitor applications, GO/Mg(OH)2 has a specific capacitance of 117.80 F g−1 at a current density of 0.5 A g−1 and 90 % cyclic capacity retention, making it an excellent candidate in modern energy storage technology.

Assembly and jamming of polar additive-swollen microgels at liquid–liquid interfaces: From inverse Pickering emulsions to functional materials

HypothesisPoly-N-isopropylacrylamide (PNIPAM)-based microgels have garnered significant interest as effective soft particulate stabilizers because of their deformability and functionality. However, the inherent hydrophilic nature of microgel restricts their potential use in stabilizing water-in-oil (W/O) Pickering emulsions. Employing diverse polar additives can improve the hydrophobicity of microgels, thus unlocking new possibilities in inverse Pickering emulsion formation and materials fabrication. ExperimentsDifferent types of microgels were generated using free-radical precipitation polymerization with tailored physiochemical properties. The effect of various polar additives on the wettability, adsorption kinetics, and interfacial coverage of microgels was systematically investigated. Additive-swollen microgels were utilized to stabilize inverse W/O Pickering emulsions, which served as templates to develop functional materials with stimuli responsiveness and hierarchical structures. FindingsAdditive-swollen PNIPAM-based microgels exhibited enhanced hydrophobicity and superior emulsifying capability, which spontaneously assembled and jammed at oil–water interfaces, resulting in a significant interfacial energy decrease. The microgels formed a tightly packed, elastic, and responsive microgel monolayer. The feasibility of the strategy was verified by preparing various inverse W/O Pickering emulsions and high internal phase Pickering emulsions (HIPPEs). More importantly, this straightforward formation strategy of microgel-stabilized inverse W/O Pickering emulsions offered a novel platform to create functional materials with customized inner structures from microscale (e.g., responsive core–shell hydrogel microspheres and colloidosomes) to macroscale (e.g., hierarchical porous materials) that can be used for potential applications, such as recyclable contaminant removal and droplet manipulation.

Recycling of water treatment plant sludge for copper adsorption from aqueous solutions

Recent studies have explored various adsorbent materials that are low-cost, available in quantity, and effective for heavy metal removal, one of them is the Water Treatment Plant (WTP) sludge. The study aimed to investigate the potential of recycling Water Treatment Plant sludge into an adsorbent for Cu (II) removal. The sludge adsorbent was carbonized by using a furnace at 600°C for 2 hours. This study was conducted in batch. The adsorbent effectiveness was analyzed by varying the dosage, contact time, and activation of the sludge adsorbent on Cu (II) removal. The adsorption isotherm was analyzed using the Langmuir and Ferundlich models, and the kinetic study used pseudo-first-order and pseudo-second-order model. The results showed the removal efficiency of Cu (II) for both activated and non-activated sludge adsorbents reached 98.6–99.9%. The addition of dosage did not affect the increase in Cu (II) adsorption capacity. Activation of the adsorbent increased the adsorption capacity of Cu (II) with the equilibrium time at 60–90 min, shorter than the non-activated adsorbent at 90–120 min. The adsorption isotherm model for both adsorbent types fitted well to the Langmuir model, indicating the adsorption process occurs in a single layer on a homogeneous surface. The adsorption kinetics followed pseudo-second-order with a high correlation coefficient. Water treatment sludge, an industrial by-product, has the potential to be an effective and low-cost adsorbent material for Cu removal.