Abstract: This study presents an innovative approach for the selective extraction of Co(II) and its separation from Ni(II) using ethyl ester glycine-betaine derivatives, specifically tri(n-pentyl)[2-ethoxy-2-oxoethyl]ammonium dicyanamide, as extractants in combi-nation with continuous-mode liquid–liquid contact. Semi-pilot-scale implementation requires non-equilibrium conditions, characterized by short contact times between ef-fluent and extractant phases. To address this, we propose dissolving analog of gly-cine-betaine ionic liquid (AGB-IL) in low-viscosity MIBK solvents to enhance mass transfer while reducing dependence on fossil-based solvents. Liquid–liquid extraction and continuous-flow stripping experiments were designed based on prior batch results and conducted in a saline environment, employing a chaotropic electrolyte for extrac-tion and a kosmotropic electrolyte for stripping. Both open and closed systems were tested to compare extractive performance with batch conditions and with scenarios representative of industrial operations. Results indicate that continuous-flow systems achieve performance comparable to batch systems in terms of extraction efficiency, Co/Ni separation coefficients, and recyclability. These findings provide proof of con-cept for the development of semi-pilot and pilot-scale processes for efficient cobalt re-covery.

Abstract: Dry reforming of methane (DRM) is an attractive route for H2 production and simultaneous CO₂ utilization, but its practical implementation is limited by catalyst deactivation. This study experimentally investigates the catalytic performance of Ni/Al₂O₃ and Gd-doped ceria–promoted Ni/GDC–Al₂O₃ catalysts for DRM in a fixed-bed quartz reactor over 400–800 °C at gas residence times of 0.1 s and 0.4 s. Increasing temperature and residence time enhanced CH₄ and CO₂ conversion as well as H₂ and CO yields for both catalysts. The GDC-promoted catalyst exhibited markedly improved activity, achieving conversions and product yields at 0.1 s comparable to those of Ni/Al₂O₃ at 0.4 s and reaching complete CH₄ conversion at about 650 °C, approximately 100 °C lower than the Ni/Al₂O₃. Long-term testing demonstrated high durability of Ni/GDC–Al₂O₃ at 650 °C with no detectable carbon deposition, consistent with thermodynamic equilibrium analysis.

Abstract: Wheat straw is an abundant agricultural residue with high potential for carbohydrate-based bioconversion, yet its efficient utilization is limited by lignocellulosic recalcitrance. This study systematically investigated Organosolv extraction of German wheat straw with the goal of achieving near-complete enzymatic hydrolysis at minimized process severity and energy demand. Process severity was evaluated using the P-Factor concept. In preliminary screening, acid catalysts and liquor ratios were assessed. Strong acids clearly outperformed weak acids: at comparable severity, 5% (w/w, DM) H2SO4 or p-toluenesulfonic acid (PTSA) yielded glucose yields of 83 ± 2.4% and 81 ± 6.2%, respectively, whereas weak acids (phosphoric, lactic, acetic) and a catalyst-free control resulted in only ~20–41% glucose yield. Liquor ratio strongly affected extraction performance; a ratio of 1:19 provided the highest glucose yield (85 ± 1.4%) and robust mixing compared to 1:12–1:15 (67–68%). Two novel pretreatment strategies applied prior to Organosolv extraction, namely hot-water pretreatment (HWP) and water pretreatment (WP), significantly increased hydrolysability compared to untreated straw (58 ± 3%), reaching 79 ± 2% for HWP and 86 ± 5% for WP. DOE-based experiments (135–170 °C; P-Factor 3.0–4.0) showed that increasing temperature from 135 to 150 °C markedly improved hydrolysability (e.g., WP: 74 ± 3% to 96 ± 3%), while further increase to 170 °C provided no additional benefit. Response-surface modeling predicted a maximum hydrolysability of approximately 88% for HWP but complete hydrolysis for WP within 152–170 °C, indicating a broad operational window. Overall, combining simple pretreatment with severity-optimized Organosolv extraction enables energy-efficient, near-complete enzymatic hydrolysis of wheat straw.

Abstract: The catalytically supported upgrading of green ethanol and green methanol mixtures can produce higher alcohols, such as iso-butanol, in a sustainable manner. Iso-butanol can be used as a feedstock to defossilize the chemical and transportation sectors. MgO-Al₂O₃ hydrotalcite-based catalysts are a promising option for this purpose. In this study, samples were synthesized using co-precipitation and urea methods with different Mg/Al molar ratios, with Ni acting as the active catalytic component. ICP-OES analysis revealed that Ni impregnation onto the hydrotalcite structure had been successful. However, in the case of the urea method, the pH value for the precipitation of Mg(OH)₂ was too low, resulting in insufficient Mg being incorporated into the hydrotalcite structure. XRD analysis revealed the presence of NiO, MgO and the spinels Al₂NiO₄ and Al₂MgO₄ in both synthesis variants, as well as elemental Ni in one sample from the urea synthesis. CO₂-TPD and NH₃-TPD experiments showed the dominance of strong basic and strong acidic catalyst centers in both synthesis pathways. The catalysts synthesized using the urea method exhibited the greatest activity, producing iso-butanol concentrations of up to 170 mmol l^-1 at 185 °C, with a maximum space-time yield of 8.2 mmol g^-1 h^-1.

Abstract: Direct air capture (DAC) of CO2 via temperature-swing adsorption (TSA) can support sustainable carbon dioxide removal, but only if sorbents regenerate with low energy demand and maintain performance under humid ambient air. Here, we evaluate three commercial molecular sieves (JLPM3, 13X and 4A) in packed-bed tests using humid ambient air. We compared 40 g samples as received with 200 g samples conditioned for 12 days at 100 °C to emulate prolonged exposure to regeneration temperature (the cumulative effect of many heating/desorption cycles); all cycle-stabilized uptake values are reported from the conditioned materials. JLPM3 delivered the highest stabilized CO2 uptake (0.24 ± 0.01 mmol·g-1), consistent with a combined physisorption/chemisorption mechanism. Its higher total porosity and smaller mesopores promoted rapid mass transfer and site accessibility, while slightly greater micropore area and volume than 13X supported its marginally higher capacity. Evidence of partial structural degradation under mechanical and thermal stress indicates that minimizing strain during cycling will be important for scale-up and for reducing sorbent replacement. Conditioning at 100 °C activated additional chemisorption sites across all sieves but reduced physisorption capacity. Importantly, a ~100 °C desorption step fully regenerated physisorbed CO2 while purging moisture from zeolite pores, indicating that low-temperature TSA (compatible with low-grade or waste heat) can replace harsher 300 °C regeneration and lower energy demand. CO2–H2O competition experiments confirmed substantial site occupancy by water vapor, which limits capture under humid conditions and motivates water-management strategies. Overall, maximizing DAC performance requires tailoring pore structure and operating conditions while preserving sorbent integrity; JLPM3 emerges as a promising candidate for more energy- and resource-efficient DAC.

Abstract:

The critical role of lithium in powering the new energy economy necessitates prioritizing efficient extraction methods. This study investigates a novel zeolitic imidazolate framework (ZIF-8)-coated manganese-based lithium ion sieve (LIS) for enhanced lithium recovery. The precursor of LIS, Li1.6Mn1.6O4, was synthesized via the hydrothermal method, followed by acid pickling to obtain the spinel lithium ion sieve H_1.6Mn_1.6O₄. The material was then immersed in a 2-methylimidazole/Zn(NO₃)₂ solution, undergoing ultrasonic-assisted hydrothermal growth to form ZIF@H_1.6Mn_1.6O₄ composites. Under optimized conditions (30 °C, pH=11, 24 h), the composite demonstrated superior lithium extraction performance compared to single-phase adsorbents, reaching 26.44 mg/g at the solution with 250 mg/L Li⁺. The adsorption capacity of the composite increased with Li⁺ concentration and reaction time. The adsorption kinetics followed a pseudo-second-order kinetic model and is dominated by chemisorption.

Abstract: Per- and polyfluoroalkyl substances (PFAS) are persistent and mobile contaminants of global concern, and while granular activated carbon (GAC) is widely used for their removal, it is limited by high regeneration and disposal costs. This study investigates surface-modified clinoptilolite zeolites as low-cost and thermally regenerable alternatives to GAC for PFAS removal from water. Natural clinoptilolite was modified through acid washing, ion exchange with Fe³⁺ or La³⁺, grafting with aminosilane (APTES) or hydrophobic silane (DTMS), dual APTES–DTMS grafting, and graphene oxide coating. Adsorption performance was evaluated for perfluorooctanoic acid (PFOA, C8) and perfluorobutanoic acid (PFBA, C4) at 100 µg L⁻¹ in single and mixed-solute systems, with an additional high-concentration PFOA test (1 mg L⁻¹). Raw zeolite showed limited PFOA removal (4%), whereas dual-functionalised APTES+DTMS zeolites achieved up to 93% removal, comparable to GAC (97%) and superior to single-silane or metal-exchanged variants. At lower concentrations, modified zeolites effectively removed PFOA but showed limited PFBA removal (< 25%), highlighting ongoing challenges for short-chain PFAS. Overall, the results demonstrate that dual-functionalised clinoptilolite zeolites represent a promising and scalable platform for PFAS remediation, particularly for mid- to long-chain compounds, provided that strategies for enhancing short-chain PFAS binding are further developed.

Abstract: The textile industries mostly rely on synthetic dyes, which contains nonbiodegradable components and high toxicity make its use environmentally hazardous. The present research delves into the unique application of proteins extracted Black Soldier Fly (BSF), as a natural dyes for wool fabrics. The hydrolyzed proteins extracted from each insect material (larvae, cocoons and flies) using superheated water at 170 °C for 1 h were used as natural dyes for dyeing wool fabrics with and without mordant (ferrous sulfate, 5% o.w.f.). Fabrics treated with mordant-free protein hydrolysate derived from cocoons showed best results with an increase in color strength (K/S value) from 0.43 to 2.78 with an increasing dye concentration from 2% to 50% o.w.f. . Color fastness to washing shows that dyed fabrics undergo variable color changes (from grade 4 to grade 1) but release little dye onto other fabrics, especially wool and synthetic fibers. Dry and wet rubbing color fastness tests showed overall variable color fastness, with little color loss on the abraded reference fabric. Overall, this work highlights the potential of protein hydrolysate from BSF as a natural and environmentally friendly dye, which may represent a promising alternative to synthetic dyes in the textile industry.

Abstract: The paper studied the effect of high-voltage short-pulse electrohydraulic discharge (HVSPED) on the processes of catalytic cracking of oil sludge in order to increase the yield of light hydrocarbon fractions. A set of laboratory experiments was carried out with varying the key parameters of HVSPED - voltage, pulse frequency and exposure time. A nanocomposite bentonite catalyst impregnated with nickel was used. The optimal electrophysical parameters of oil-sludge treatment by HVSPED were determined, providing the maximum yield of gasoline and kerosene fractions. The effectiveness of HVSPED treatment of oil sludge in the presence of a catalyst was confirmed by DTA–thermogravimetric analysis and chromatographic-mass spectral analysis of the light and middle fractions of the hydrogenate. The proposed approach made it possible to enhance the resource and energy efficiency of oil-sludge processing using HVSPED, demonstrating high potential for further industrial application.

Abstract:

This article presents the design, synthesis and application of novel C₈/PW₁₂O₄₀³⁻–IL Janus nanopaticles for highly efficient, recyclable catalytic degradation of methyl orange (MO) in wastewater. The catalyst's innovative asymmetric architecture comprises a hydrophobic C₈ hemisphere that selectively adsorbs and pre-concentrates MO molecules, and a catalytic phosphotungstate-ionic liquid hemisphere that activates oxidants to generate hydroxyl radicals for rapid dye degradation. A magnetic Fe₃O₄ core facilitates instantaneous catalyst recovery. This "collect, degrade, and separate" mechanism synergistically results in exceptional performance, surpassing that of many conventional homogeneous and heterogeneous systems, as validated through comparative analysis. This work establishes a strategic paradigm for designing smart, multifunctional materials that combine targeted interfacial engineering with practical recyclability for advanced environmental remediation.

Abstract: The study investigates the kinetics of redistribution of oils, resins, and asphaltenes in high-viscosity oil from the Karazhanbas field during ultrasonic treatment (22 kHz, 50 W) in the presence of a zeolite catalyst (1.0% by mass). The parameters of the technological process - temperature range from 30 to 70°C, exposure time from 3 to 11 min - were established, which lead to an increase in oil content (by 14.8%), and a decrease in the concentration of resins (by 12.2%) and asphaltenes (by 2.6%). An increase in the conversion rate between oil components is observed until the 7th minute of treatment. Group analysis of light and medium oil fractions showed an increase in the content of paraffinic, naphthenic, benzene and olefinic hydrocarbons while reducing the proportion of naphthalenes and heteroatom compounds. The results obtained confirm the effectiveness of ultrasonic-catalytic treatment for the structural destruction of high-viscosity oil and the formation of lighter hydrocarbon fractions.

Abstract: Electrochemical mechanical polishing (ECMP) has emerged as a promising alternative to conventional chemical mechanical polishing (CMP), particularly for addressing challenges in planarizing ruthenium (Ru)—a critical barrier-layer material in advanced copper interconnects. This study systematically investigates the triboelectrochemical behavior and underlying mechanisms of ruthenium during ECMP, with a focus on the effects of mechanical power (induced by load and rotational speed) and applied potential. Through open-circuit potential measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS), we demonstrate that mechanical energy input significantly enhances electrochemical reactions, with rotational speed exerting a more pronounced influence than applied load. Notably, the corrosion potential increases with load at constant speed, while the friction coefficient rises as rotational speed decreases. EIS analyses further reveal that higher rotational speeds promote the formation and growth of a thicker passive oxide film on ruthenium surfaces. These insights provide a theoretical foundation for optimizing ECMP processes toward high-efficiency, high-selectivity, and low-damage planarization of Ru-based interconnect structures.

Abstract: In the Yucatán Peninsula, Citrus aurantium L. has a strong cultural and culinary relevance where local industries already process its juice and essential oils, producing large amounts of by-products. In this context, green chemistry strategies have accelerated the valorization of agro-industrial residues, where natural deep eutectic solvents (NADES) stand out due to their low cost, ease of preparation, and high extraction efficiency. This study focuses on evaluating different NADES combinations for the extraction of bioactive compounds from C. aurantium by-products, followed by essential oil (cold pressing) and juice (mechanical pressing) extraction. A 3×2×2 factorial design was implemented to evaluate the effect of hydrogen bond donor (HBD: fructose, glucose and glycerol), molar ratio (MR: 1:1 and 1:2 mol/mol choline chloride (ChCl) :HBD and added water (AW: 50 and 70%) on the polyphenolic profile, total phenolic content, total flavonoid content, ascorbic acid content and antioxidant capacity. HBD was the most critical factor in the extraction of bioactive compounds, the extract obtained with glycerol and 70% AW exhibited the highest hesperidin content (2186.08 mg/100 g dry mass), while the same HBD with 50% added water exhibited the highest quercetin + luteolin extraction (721.32 mg/100 g dry mass), both at same MR (1:1 mol/mol). Glycerol also achieved the highest recovery of total flavonoids (1829.7 ± 17.85 mg quercetin equivalent/100g dry mass) with a MR of 1:2 mol/mol and 70% AW. Finally, all other maximum values were obtained with fructose-based NADES: the highest total phenolic content (3603. 7 ± 52.9 mg gallic acid equivalent/100 g dry mass) was achieved at MR of 1:1 mol/mol and 50% AW, while for both, vitamin C (1964.8 ± 33.7 mg ascorbic acid equivalent/100g dry mass) and antioxidant capacity (84.31% inhibition) the maximum was reached at MR of 1:2 mol/mol and 50% AW.

Abstract:

Tropical fruit waste composed of peels, pulp, and discards, presents a growing disposal challenge in high and rising fruit production regions. This review explores transforming this waste into bioethanol which can also be defined as a clean-burning biofuel. It examines pre-treatment techniques like enzymatic and acidic hydrolysis that explains how complex carbohydrates is broken down into fermentable sugar efficiently. These techniques are very much required for a complete and efficient production of bioethanol. Additionally, the study focuses on optimizing fermentation conditions, including temperature, yeast strain selection, and nutrient supplementation, to maximize bioethanol yield. The impact of fruit ripeness on bioethanol yield is discussed, noting how sugar content changes during ripening affecting the ethanol output. Saccharomyces cerevisiae , a robust fermenting agent, is highlighted for its potential in bioethanol production. The feasibility of bioethanol production from various fruit substrates using a simulation model is highlighted. The model incorporates key factors such as substrate concentration of glucose, yeast cell density where various parameters of Saccharomyces cerevisiae is considered, and ethanol production. While the simulation results exhibit similar trends for different fruits, factors like model simplifications and parameter sensitivity can influence the outcomes. By integrating findings from various studies and other sources, this review aims to develop a cost-effective and sustainable bioethanol production process using tropical fruit waste.

Abstract: Biofuels offer potential to mitigate climate change, increase energy security, and economically support farmers around world. Licuri (Syagrus coronata) could be an important biofuel feedstock because its kernel (edible seed) has high energy content. This research investigates optimal reaction conditions to convert fatty acids (FA) and fatty acid methyl esters (FAME) (including licuri biodiesel) to hydrocarbons via deoxygenation in a trickle-bed reactor over granular Pd/C catalysts. Our results indicate that a 20 wt.% palmitic acid (PA) feed is optimum for continuous deoxygenation at 300 °C and 15 bar in 5% H2/He because of decarboxylation inhibition at higher concentrations. Deoxygenation rates are higher for PA than for methyl palmitate (MP) because of the slow initial hydrogenolysis of the methoxy bond over Pd/C. The hydrocarbon product distributions from deoxygenation of licuri biodiesel were fully consistent with FA decarboxylation and decarbonylation. A lab-prepared 5 wt.% Pd/C catalyst with higher metal dispersion provided modestly higher hydrocarbon yields from licuri biodiesel than a commercial 1 wt.% Pd/C catalyst.

Abstract: The ability to predict the vapor pressure and vapor-phase composition of hydrocarbon mixtures (such as jet fuel or its un-refined precursors) and partially vaporized hydrocarbon mixtures is important to simulations of processes that involve vaporization. For example, models or simulations of distillations, flash point, chemical/combustion properties of the vapor phase of partially vaporized systems, and jet-engine ignition all benefit from a rudimentary model of vapor pressure given inputs of liquid-phase composition and temperature. One approach toward the rudimentary model is Raoult’s Law which is elegantly simple (\( p_i=x_i*P_(vap,i) \)) but inaccurate at low mole fraction (\( x_i \)). Another approach is to use a so-called activity coefficient (\( a_i \)) to more accurately represent the partial pressure of the ith component (\( p_i=a_i* x_i*P_(vap,i) \)) where the activity coefficient is estimated from an algebraically complex formula (e.g. the UNIFAC model) involving a plurality of combinations of mole fractions, molecular group fractions, Van der Waals volume and area as well all possible interaction terms between the groups. Invariably, the corrections based on activity coefficients involve an empirical fit to vapor pressure data that is sparsely (if at all) populated by mixtures that resemble fuel either in regard to the number of components or even the mole fraction of a given component. For example, the reference, “average” conventional jet fuel designated as “A-2” by the National Jet Fuel Combustion Program which has been leveraged by numerous research studies contains just 4.3%m n-nonane, its most populous component, while the simple mixtures used to anchor vapor pressure models such as UNIFAC are unlikely to have any component present at less than 10%mol. In addition to a lack of validation to naturally representative mole fractions, models such as UNIFAC can be computationally burdensome for simulations that require a very large number of vapor pressure and composition determinations. Here we present an alternative correction to Raoult’s law where the vapor pressure of the ith component is represented by a modified form of the Clausius-Clapeyron equation where the reference temperature (\( T_(ref) \)) is replaced by a simple algebraic function that converges to \( T_(ref) \) as \( x_i \) approaches 1 while smoothly increasing from this value as \( x_i \) decreases. Simultaneously, the heat of vaporization (\( ΔH_(vap,i) \)\( T \)) term is replaced by another simple algebraic expression that converges to \( ΔH_(vap,i) \) \( T \) as \( x_i \) approaches 1 while smoothly decreasing as \( x_i \) decreases. In this model, the temperature dependent heat of vaporization is tuned at each temperature such that the Clausius-Clapeyron equation reproduces the correct vapor pressure of the neat material while the parameterized algebraic corrections are tuned to vapor pressure data of mixtures involving n-pentane, toluene, and dodecane where the mole fraction of n-pentane and toluene are maintained below 10%mol. Validation of the resulting model is accomplished by comparing modeled vapor-liquid equilibrium systems with experimental measurements.

Abstract: In recent years CO2 reforming of methane has attracted great interest as it produces high CO/H2 ratio syngas suitable for the synthesis of higher hydrocarbons and oxygenated derivatives, since it is a way for disposing and recycling two greenhouse gases with high environmental impact, CH4 and CO2, and because it is regarded as a potential route to store and transmit energy due to its strong endothermic effect. Along with noble metals, all the group VIII metals, except for osmium, have been studied for catalytic CO2 reforming of methane. It was found that the catalytic activity of Ni, though lower than those of Ru and Rh, was higher than the catalytic activity of Pt and Pd. Although noble metals have been proved to be insensitive to coke, the high cost and restricted availability limit their use in this process. It is therefore valuable to develop stable Ni-based catalysts. In this contribution, we show how their activity and coking resistivity is greatly related to the size and dispersion of Ni particles. Well-dispersed Ni nanoparticles were achieved by multistep impregnation on a mesoporous silica support, namely SBA-15, obtained through a sol-gel method, using acetate as nickel precursor and keeping the Ni loading between 5 wt% and 11 wt%. Significant catalytic activity was obtained at temperatures as low as 450 °C, temperature well below their deactivation temperature, i.e., 700 °C. For the pre-reduced samples complete CO2 conversion was obtained around 680 ºC. As such, their deactivation by sintering and coke formation was prevented. To the best of our knowledge, no Ni-based catalysts with complete CO2 conversion at temperatures lower than 800 ºC were reported so far.

Abstract: This study evaluates the efficiency of biodegradable polyurethane foams as thermal insulation materials compared to conventional materials like expanded polystyrene (EPS). Key parameters analyzed include thermal conductivity, energy savings, CO₂ emission reductions, and investment payback periods. Biodegradable polyurethane foams demonstrated a thermal conductivity of 0.022 W/(m·K), significantly lower than EPS's 0.035 W/(m·K), leading to higher energy savings. Calculations reveal an annual energy saving of 443,820 kWh for polyurethane foams, compared to 441,330 kWh for EPS. Financially, polyurethane foams save approximately €53,258.4 annually, while EPS saves €52,959.6. In terms of environmental impact, polyurethane foams reduce CO₂ emissions by 88,764 kg annually, versus 88,266 kg for EPS. Despite the higher initial cost of polyurethane foams (€50/m² compared to €30/m² for EPS), the payback period is remarkably short at 0.094 years (1.13 months) compared to EPS's 0.057 years (0.68 months). These findings high-light biodegradable polyurethane foams as a superior option for thermal insulation, offering significant energy, financial, and environmental benefits.

Abstract: The increasing generation of liquid waste from agricultural, industrial, and municipal sources poses significant environmental challenges due to its high content of organic carbon (OC) and nutrients such as phosphorus and nitrogen. This review examined the effectiveness of membrane-based technologies, particularly microfiltration (MF) and ultrafiltration (UF), in separating and recovering these valuable compounds. Drawing on key literature indexed in Scopus, the review analyzed how membrane properties, operating conditions, and feed characteristics influence removal efficiency. The find-ings indicate that MF membranes primarily retain particulate organic matter and sus-pended solids (SS), with limited retention of phosphorus and nitrogen species. In con-trast, UF membranes exhibited superior performance in removing both OC and phos-phorus, and partially retain some nitrogen compounds depending on molecular size and charge. When combined with pre-treatment processes such as coagulation or ad-sorption, both MF and UF achieve higher nutrient removal rates. These membrane technologies showed promise not only in reducing pollutant loads but also in enabling nutrient recovery for potential reuse in agriculture. The optimization of membrane configuration and integration with other processes is essential for enhancing treatment performance and contributing to circular wastewater management strategies.

Abstract: Coagulation–flocculation, historically reliant on simple inorganic salts, has evolved into a technically sophisticated process that is central to the removal of turbidity, suspended solids, organic matter, and an expanding array of micropollutants from complex wastewaters. This review synthesizes six decades of research, charting the transition from classical aluminum and iron salts to high-performance polymeric, biosourced, and hybrid coagulants, and examines their comparative efficiency across multiple performance indicators—turbidity removal (>95%), COD/BOD reduction (up to 90%), and heavy metal abatement (>90%). Emphasis is placed on recent innovations, including magnetic composites, bio–mineral hybrids, and functionalized nanostructures, which integrate multiple mechanisms—charge neutralization, sweep flocculation, polymer bridging, and targeted adsorption—within a single formulation. Beyond performance, the review highlights persistent scientific gaps: incomplete understanding of molecular-scale interactions between coagulants and emerging contaminants such as microplastics, PFAS, and engineered nanoparticles; limited real-time analysis of flocculation kinetics and floc structural evolution; and the absence of predictive, mechanistically grounded models linking influent chemistry, coagulant properties, and operational parameters. Addressing these knowledge gaps is essential for transitioning from empirical dosing strategies to fully optimized, data-driven control. The integration of advanced coagulation into modular treatment trains, coupled with IoT-enabled sensors, zeta potential monitoring, and AI-based control algorithms, offers the potential to create “Coagulation 4.0” systems—adaptive, efficient, and embedded within circular economy frameworks. In this paradigm, treatment objectives extend beyond regulatory compliance to include resource recovery from coagulation sludge (nutrients, rare metals, construction materials) and substantial reductions in chemical and energy footprints. By uniting advances in material science, process engineering, and real-time control, coagulation–flocculation can retain its central role in water treatment while redefining its contribution to sustainability. In the systems envisioned here, every floc becomes both a vehicle for contaminant removal and a functional carrier in the broader water–energy–resource nexus.