The synergistic extraction of rare earth elements (REEs) from industrial wet-process phosphoric acid (WPPA, 29 wt% P2O5) was investigated using binary solvent extraction systems composed of an organophosphoric acid extractant, Di-(2-ethylhexyl) phosphoric acid (D2EHPA) and diglycolamide-type ligands (DGAs) including N,N, N ',N '-tetraoctyldiglycolamide (TODGA) and N,N-di(2-ethylhexyl)-diglycolamic acid (HDEHDGA) in kerosene. The D2EHPA-DGA systems exhibited prominent synergism, noticeably improved the extraction efficiency and the selectivity compared to the use of individual extractants. The optimal extraction was achieved using D2EHPA (1.8 M) combined with TODGA (0.2 M), which showed high selectivity toward all REEs, with no significant co-extraction for other impurities. Overall extraction efficiencies reached 87% for all REEs and up to 95% for yttrium (Y) as the predominant Heavy REEs in the WPPA. Light REEs were also effectively recovered, with efficiencies of 60% for lanthanum (La), 78% for cerium (Ce) and neodymium (Nd). Two-stage cross-current extraction, D2EHPA-TODGA system achieved an overall REEs yield of 96%. Scandium (Sc) showed a slight improvement using D2EHPA-TODGA system over 60%, indicating limited synergism. The spectroscopic studies (FT-IR and NMR) confirmed the formation of mixed-ligand complexes stabilized by hydrogen bonding and coordination involving the phosphoryl (P=O) and amid (-CONH-) groups. Moreover, stripping experiments revealed that only H2SO4 enabled effective stripping of light REEs, achieving 76% for La and 53% for Ce.

This study investigates the functionalization of microcrystalline cellulose (MCC) and its application as a sustainable reinforcement for cementitious materials, while promoting the valorization of purified phosphogypsum (PPG) in cementitious materials. MCC was extracted from quinoa stalks and subsequently functionalized through carboxylation, phosphorylation, or sulfonation to modify its surface chemistry while preserving the integrity of the cellulose polymeric backbone. A systematic comparison of the functionalized MCCs enabled direct correlations between macromolecular surface functionality and cement performance. Solid-state 13C and 31P NMR analyses verified the successful introduction of the functional groups, and elemental quantification confirmed the effective incorporation of carboxyl, phosphorus, and sulfur functionalities with degrees of substitution of 0.033, 0.51, and 0.35, respectively. The functionalized MCC materials were incorporated into PPG-based cement pastes at low contents (0.1-2.0 wt%) as a bio-based macromolecular reinforcing additive. Flowability measurements revealed a progressive decrease with increasing MCC content, while functionalized MCCs improved dispersion and maintained higher workability compared to unmodified MCC. At an optimal content (0.2 wt%), functionalized MCCs significantly enhanced hydration efficiency and mechanical performance, without altering the main hydration phases, as evidenced by XRD, TGA, and FTIR analyses. Carboxylated MCC exhibited the most pronounced effect, increasing the 28-day compressive and flexural strengths by 49.1% and 38.7% respectively compared to CEM II/B-M 32.5. These results highlight the potential of functionalized quinoa-derived MCCs for PPG-based cement materials, thereby supporting the circular use of agro-wastes and phosphogypsum by-products in construction materials.

The phosphate rock (PR) is a naturally occurring radioactive material. Univariant statistical and principal component analyses (PCA) revealed that U/Ra-rich phosphates originate from sedimentary rock with higher median activity concentrations of 238U and 226Ra, approximately 1200 and 1146 Bq/kg, respectively. Conversely, Th/K-rich phosphates typically derive from igneous rock, with median activity concentrations of 232Th and 40K, approximately 331 Bq/kg, respectively. The PR processing through the wet-process phosphoric acid production disrupts the radionuclide secular equilibrium. Consequently, radionuclides present in PR are preferentially partitioned either to phosphoric acid or phosphogypsum (PG). Over 98 wt% of 226Ra partitioned into PG as a small co-precipitated barite crystal ((Ra-Ba)SO4), while more than 98 wt% of 232Th partitioned into PG either as Th(SO4)2 mineral phase associated with gypsum crystals or hosted by Th-bearing minerals residues. In contrast, over 98 wt% of 238U partitioned into phosphoric acid, primarily as UO2HPO4 complex. Specifically, PG contains about 0.012-0.023 mg of 226Ra per ton of PG, resulting in an average 226Ra activity concentration of 682 Bq/kg. Furthermore, many technologies for radionuclides recovery/ removal from PG were evaluated. Organic chelating-based processes demonstrated excellent selectivity toward radionuclides present in PG. However, this approach remains in laboratory-scale due to higher reagents cost. On the other hand, granulometric separation provides a simple treatment route, enabling the isolation of radionuclide-enriched fractions with scalable potential. Future research should prioritize the development of an integrated industrial process for 226Ra recovery that simultaneously enables the production of radionuclide-free PG, ensuring the overall economic viability of the process.

This study evaluated the effects of fly ash (F) and effective microorganisms (EM) on nutrient dynamics and heavy metal transformations during vermicomposting of camel manure (CM). Four treatments (CM, CM + F, CM + EM, and CM + F + EM) were arranged in a completely randomized design and monitored over 12 weeks. Significant (p < 0.05) treatment and time interactions were observed for pH, NH4-N, Mn, Pb, and Mo. The addition of EM resulted in a greater decline in pH compared to other treatments. After 12 weeks, Olsen P increased from 300.62 to 398.71 mg/kg in CM + EM, while NH4-N increased markedly from 22.74 to 86.62 mg/kg. In contrast, NO3/NO2-N declined in EM-amended treatments but increased in the control and CM + F. Trace metal concentrations generally increased due to mass reduction during vermicomposting yet remained within internationally acceptable limits. Germination index (GI) values varied significantly among crops and treatments, ranging from phytotoxic to non-phytotoxic responses. Although CM + EM produced superior nutrient enrichment, several vegetables exhibited GI values below 50%, indicating potential phytotoxicity for sensitive crops. In case of established crops for which nutrient supply outweighs early phytotoxic concerns, CM + EM represents the most agronomically beneficial option. Future studies should explore blending CM + EM and CM + F with stabilizing amendments such as biochar to optimize nutrient availability while minimizing salinity and phytotoxic risks.

ABSTRACT Biopolymer‐based nanocarriers have become promising systems for sustained ion delivery due to the tunability of their polymeric network structure. In this study, crosslinked chitosan‐tripolyphosphate (CS‐TPP) nanocarriers were formulated and optimized using a Box‐Behnken design to test how different formulation parameters affect the properties of the nanoparticles. The improved formulation made nanoparticles that were less than 452 nm in size and had high entrapment efficiencies (>87%). FTIR, XRD, DSC, SEM‐EDX, and DLS all showed that a crosslinked polyelectrolyte network had formed and that divalent metal ions (Fe 2 + , Cu 2 + , Zn 2 + ) had been successfully added. We used swelling analysis and release experiments to look into the connection between network structure and transport behavior. The nanocarriers showed a biphasic release pattern, with an initial burst followed by steady diffusion over eight days. Kinetic modeling with the Korsmeyer–Peppas equation showed that transport was controlled by Fickian diffusion (n < 0.45). The differences in release behavior were due to differences in the strength of the metal‐polymer interaction, which changes the network's compactness and diffusion pathways. These results show that process parameters control the structure and transport properties of the network, which allows for tunable sustained release behavior.

Being a major contributor to the global greenhouse gas emissions, the cement industry targets net-zero emissions by 2050 through lowering clinker CO2 emissions via low-carbon raw materials and partial substitution of clinker with supplementary cementitious materials (SCMs). This study explores a sustainable approach to low-carbon cement through the dual integration of phosphogypsum (PG) and fly ash (FA) by-products as SCMs for potential CO2 reduction. The synergistic effect of PG and FA on cement properties was investigated at different substitution rates of clinker. The results showed that the optimized mortar containing 10

Organic dyes photodegradation solely under visible light represent a low cost and interesting solution for issues related to deterioration of water conditions. In this research study, cellulose acetate (CA) micro/nanofibrous membrane nano-doped has been prepared and tested for orange G dye degradation. Indeed, sulfur-doped titanium dioxide (S-TiO2) nanoparticles as photocatalytic spices were prepared following mechano-synthesis approach and fully characterized using infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD) and transmission electronic microscopy (TEM). Afterward, the prepared S-TiO2 nanoparticles were incorporated into cellulose acetate to elaborate nano/micro fibrous membrane using electrospinning method. Once the membrane elaboration has been optimized, orang G dye photodegradation under visible light was investigated, compared to the result of photo degradation using TiO2 under UV light and very interesting results were obtained. This work provides valuable insight into the design of sustainable and fibrous membranes for organic pollutants photo-degradation and affords a promising stand for future low-cost water remediation technologies.

Phosphogypsum (PG) is a byproduct generated during the production of phosphoric acid according to the wet-process phosphoric acid (WPPA) route in Morocco. The integration of PG in construction materials is limited due to the presence of impurities such as P2O5, F, heavy metals, and radionuclides. This work describes the use of a simple PG purification process, to allow the utilization of large quantities of Moroccan PG in Portland cement (PC) production. PC was modified using different amounts of PPG ranging from 0 to 15 wt.

A soft strategy for the phosphorylation of cellulose and starch has been developed to produce functionalized bio-absorbents (P-Cellulose / P-Starch) for the decontamination of polluted water. The proposed synthesis pathway utilizes only phosphorus pentachloride (PCl5), without the need for urea or acids. The biopolymers were successfully phosphorylated, as confirmed by structural characterization techniques, including solid-state (NMR), x-ray diffraction (XRD), infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Furthermore, detailed insights into the morphological and structural changes as well as the adsorption capabilities of the prepared materials, were thoroughly discussed using results from scanning electron microscopy (SEM), potential zeta measurement, and inductively coupled plasma spectrometer (ICP). Remarkably, the prepared bio-absorbents exhibited enhanced sorption properties for Methylene Blue (MB) through a wide pH range compared to their native forms. These findings shed light on how the molecular structure, reactivity, networking, and functional groups of P-Cellulose and P-Starch contribute to adsorptions efficiency. In addition to demonstrating the bio-absorbents regeneration and reuse, the prepared materials achieved heavy metal removal efficiencies of u to 70 %, significantly outperforming their native forms, which removed only 30 %. This highlights the critical role of phosphate groups and flexible networks in the uptake of contaminants from water.

In this study, a straightforward granulometric separation process was developed to efficiently purify the phosphogypsum (PG). The distribution and occurrence states of different impurities present in the PG including phosphorus (P), fluorine (F), heavy metals and rare earth elements (REEs) were thoroughly investigated. Impurity-bearing phases were identified and physically isolated. Results revealed that over 98 wt% of F is enriched in coarse PG fraction (> 250 mu m), primarily hosted in co-crystallized malladrite (Na2SiF6) and fluorite (CaF2) phases. Malladrite was also identified along with quartz (SiO2) as the primary Si-Na-bearing phases, collectively accounting for 99 wt% of these elements across all PG fractions. Apatite (Ca-5(PO4)(3)(F)), enriched in the coarse fraction, was identified as the dominant P-REE-bearing phase. Heavy metals were also mainly found in this fraction, either substituting for Ca-2(+) in gypsum or apatite lattices, or adsorbed onto Si-Al-Fe-bearing phases. Removal of the coarse PG fraction improved material purity from 96 % to 98 %, enabling its efficient use in cement formulations. As a result, the compressive and flexural strengths of the mortar containing purified PG increased from 33.4 and 7.8 MPa to 36.3 and 8 MPa, respectively, in comparison with mortars prepared with raw PG.

ABSTRACT Photoresponsive polymers have emerged as a dynamic class of materials exhibiting a response to light. On the other hand, amphiphilic polymers are materials possessing both hydrophobic and hydrophilic sides in their macromolecular structure. The particularity of amphiphilic polymers is that they can simultaneously interact with hydrophobic and hydrophilic environments, leading to self‐assembly. The combination of these intriguing photosensitive and amphiphilic properties has spurred the development of amphiphilic photoresponsive polymers with adaptable features. Exposure to light triggers changes in the polymers’ properties, which can be exploited to influence the formation and stability of diverse nanoscale structures such as core–shell micelles, worm‐like micellar assemblies, vesicles, and other complex macromolecular architectures. This precise control over polymer behavior has propelled these materials to the forefront of research and innovation. This review sheds light and classifies the main photosensitive chemical groups used to design such photoresponsive polymers. Furthermore, a concise overview and a discussion about the synthesis pathways of photoresponsive polymers, with or without amphiphilic behavior, are presented, followed by a projection of potential opportunities raised by these polymers to improve controlled agrochemicals release area.

Agriculture today faces the challenge of increasing food production while minimizing the environmental impacts of agricultural practices, particularly the inefficient use of fertilizers. To address this issue, researchers have explored the potential of controlled-release fertilizers (CRFs) capable of releasing nutrients at a controlled rate over an extended period. However, the use of non-biodegradable polymer coatings in many commercial CRFs raises environmental concerns. This study investigates the potential of incorporating Moroccan Ghassoul clay, modified or natural, into fertilizer granules to modulate nutrient release profiles. The unique physicochemical properties of clay minerals potentially grant them the ability to adsorb and release essential nutrients gradually over time. The modification of the ghassoul clay was performed using the pillaring technique, which creates a. complex microstructure that can restrict the transfer of water molecules and nutrients. The characterization of pillared and non-pillared clays was performed using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), providing insights into the influence of pillaring on basal spacing and interlayer structure. The morphological analysis was conducted using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). It was found that incorporating pillared clay into fertilizers improved the physical properties of granules compared to those incorporating untreated clay and non-incorporated ones. Nutrient release tests assessed using three phosphatic fertilizers through sand column revealed that the use of untreated clay resulted in faster nutrient release due to its inherent swelling properties, facilitating granule disintegration upon contact with water. In contrast, granules co-granulated with pillared clay exhibited a slower release of nutrients, suggesting increased efficiency under specific conditions. The findings demonstrate the incorporation of clay emerges as an effective strategy for modulating nutrient release rates, whether accelerating or slowing, enabling improved fertilization optimization, and potentially addressing environmental concerns.

Environmental negotiations are complex, and conveying the interaction between science and policy in traditional teaching methods is challenging. To address this issue, innovative educational approaches like serious gaming and role-playing games have emerged. These methods allow students to actively explore the roles of different stakeholders in environmental decision-making and weigh for instance between sometimes conflicting UN Sustainable Development Goals or other dilemmas. In this work the phosphorus negotiation game (P-Game) is for the first time introduced. We present the initial quantitative and qualitative findings derived from engaging 788 students at various academic levels (Bachelor, Master, PhD, and Postdoc) across three continents and spanning 22 different countries. Quantitative results indicate that female participants and MSc students benefitted the most significantly from the P-Game, with their self-reported knowledge about phosphorus science and negotiation science/practice increasing by 71–93

Drought stress is becoming a structural phenomenon in cropping systems challenged by climate change and soil fertility degradation. A balanced fertilization strategy based on nitrogen, phosphorus, and potassium as well as on silicon supplementation was tested as an efficient practice to improve maize tolerance to short-term drought stress. Three fertilization strategies (control: treatment with zero NPK fertilizer application; NPK: granular NPK fertilizer, and NPK + Si: granular NPK fertilizer enriched with 5

Organophosphorus compounds (OPC) are a large class of organic compounds that provide a wide range of applications, and their importance has grown steadily in recent years. In each category and family, these compounds have similarities and differences. Due to their immense variety, these chemicals have various properties and, therefore, various applications. In fact, various works have been published recently that present the main applications of OPC, especially in metal extraction. Despite their extemsive range of use, optimizing their performance as extractant agents remains a challenge due to their structural variability and sensitivity to process parameters. This review provides a critical analysis of pentavalent OPCs, focusing on how their chemical nature influences heavy metal extraction efficiency. For the first time, we present a novel classification system for OPCs based on phosphorus valency and heteroatom coordination, offering a framework to guide future research. Our findings reveal that the direct coordination of the phosphorus to heteroatoms such as oxygen, sulfur, and nitrogen has a great influence on the physicochemical characteristics of the extractant and the metal extraction efficiency. This observation is in line with Pearson’s Hard and Soft Acids and Bases (HSAB) theory in the sense that it demonstrates that altering the heteroatom alters the metal affinity of the ligand. As a result, these structural modifications can improve the extraction performance by up to 40% for some heavy metals, highlighting the potential for optimized molecular designs to maximize industrial applications. In the future, this work offers a solid foundation for future studies on the rational design of organophosphorus-based extractants. Using HSAB theory and our novel classification system, researchers can rationally design OPCs for their target metal with unparalleled precision. These results have transformative impacts on metal recovery efficiency-intensive sectors like mining, waste recycling, and clean energy technologies.

In this study, a novel hydrometallurgical process involving two leaching stages was developed to efficiently recover both phosphorus (P) and rare earth elements (REEs) from carbonatite ore of igneous origin. The mineral assemblages and geochemical composition of the carbonatite ore was thoroughly investigated by an integrated approach combining petrographic, mineralogical, and geochemical analyses. It was revealed that REE-bearing phases (mainly phosphates, i.e., apatite and monazite) are associated with the predominant carbonate gangue minerals (i.e., dolomite/calcite) in the studied sample. In the first stage, these gangue minerals were selectively leached, achieving a removal efficiency of over 95 %. As a result, the content of REEs increased from similar to 0.2 wt% in the raw carbonatite ore to 0.7 wt% in the preconcentrated solid residue following the selective leaching of carbonate gangue minerals, demonstrating an efficient enrichment of REEs by 3.5-fold compared to the raw material. In the second stage, Response Surface Methodology (RSM) was used to optimize REEs and P extraction from the residue, revealing acid concentration and temperature as crucial factors. Optimal conditions resulted in maximum recovery rates of 78 % for Ce, 75 % for La and 94 % for P.

Rare earth elements (REEs) have gained global attention as strategic compounds for the transition to a green and sustainable economy due to their exceptional physicochemical properties and nuanced ionic radius differences. The worldwide demand for REEs is rising steadily, fueled by integration into advanced technologies such as electric vehicles, wind turbines, mobile devices and computers. Various methods have been devised to extract REEs from primary and secondary resources, including ion exchange resin, solvent extraction (SX), membrane separation, precipitation, crystallization and adsorption. SX emerges as the primary process for REEs separation and recovery, evolving with diverse extraction solvents guided by a balance between the efficiency and the cost. This review explores current trends in SX technologies, with a particular emphasis on extraction methodologies applicable to various acidic media. It provides a comprehensive evaluation of existing technologies, considering efficiency, selectivity, and technical feasibility. Through this discussion, researchers gain a nuanced understanding of the evolving landscape of SX technologies, informed by considerations of both current capabilities and future prospects.

Phosphate fertilizers are produced using phosphoric acid as a vital chemical component. This essential ingredient is typically derived from phosphate rock, through a wet process phosphoric acid (WPPA). However, the WPPA contains impurities, including heavy metals (HMs) like cadmium (Cd), zinc (Zn) and copper (Cu), as well as unwanted elements like iron, and other valuables elements, notably rare earth elements (REEs) such as yttrium (Y), holmium (Ho) and ytterbium (Yb). The current study aims to develop a novel process for a simultaneous and selective recovery of HMs and REEs through solvent extraction from WPPA. Single-stage extraction, cascade extraction and synergistic extraction were explored to gain a deeper understanding of the mechanisms and identify the most efficient process. 90, 80 and 99 % for Y, Ho and Yb, respectively, were extracted using D2EHPA. While 89 % for Zn, 99 % for Cu and Cd were removed using Cyanex 301. On the other hand, 60 % of Yb, 74 % of Y and 78 % of Ho were stripped using H2SO4, while 98 % of Cd and 99 % of Zn were stripped using HCl. The organic phase can be successfully reused with an effective extraction and stripping. Oxalic acid (C2H2O4) was employed to precipitate REEs. However, sodium carbonate (Na2CO3) was used to precipitate HMs. Finally, solvent extraction was carried out on WPPA solution to ensure the extraction performance under industrial conditions.