Adsorption Separation Research Articles

Adsorption Separation of Various Polar Dyes in Water by Oil Sludge-Based Porous Carbon

The pollution caused by printing and dyeing wastewater is increasingly severe, posing significant harm to aquatic plants and animals. In this study, porous carbon was synthesized via the high-temperature pyrolysis of light and heavy organic matter present in oily sludge, utilizing low oil content sludge as the raw material and zinc chloride as a chemical activator. The results exhibited a significant increase in the specific surface area of the oily sludge-based porous carbon, from 4.95 m²/g to 10.95 m²/g. The effects of various parameters such as pH, amount of sorbent, dye concentration, temperature, and contact time on dye removal have been studied. The results showed that the oil sludge-based porous carbon exhibited high efficiency in removing Malachite Green from aqueous solutions, which has low polarity and remains consistently above 97%. The removal rate of Crystal Violet, which is more polar, was as low as 24.14%. The corresponding adsorption capacities were 33.41 mg/g for Malachite Green, 16.41 mg/g for Crystal Violet, and 13.56 mg/g for Methylene Blue. The adsorption capacity of OSC700 for three types of dyes was characterized by monolayer adsorption, primarily driven by chemical adsorption, with significant contributions from electrostatic and hydrophobic effects. The adsorption process was spontaneous, exothermic, and accompanied by an increase in entropy. For less polar substances, the adsorption on oily sludge-based porous carbon is primarily driven by aromatic functional groups on the carbon surface, hydrophobicity, π-π electron-donor-acceptor (π-π EDA) interactions, and surface hydrogen bond formation. In contrast, for more polar dyes, electrostatic and hydrophobic interactions dominate, with electrostatic adsorption being the predominant mechanism and minimal hydrogen bond formation during adsorption.

Construction of negative electrostatic sugared gourd pore within nickel-based metal-organic framework for one-step purification acetylene from ethylene and carbon dioxide mixture

The development of highly efficient adsorbents for purifying acetylene from multi-component mixtures is crucial in the chemical industry, yet the tradeoff between renewability and selectivity severely constrains practical industrial applications. This study introduces sugar gourd pore framework (SGPF-1), an innovative ultra-microporous framework synthesized using 1,2-di(4-pyridyl)ethylene (BPE), 4,4′,4′’-nitrilotribenzoic acid (NTA), and hexanitronickel under solvothermal conditions. The X-ray diffraction analysis has been used to prove the detailed structure and phase purity of SGPF-1. The structure of SGPF-1 was tailored for selectively adsorbing and separating the target compound, C2H2. The negative electrostatic effect, inspired by the natural sugared gourd structure, enhances the selectivity and adsorption capacity for C2H2, while minimizing the interaction with impurities like C2H4 and CO2. Experimental data show that SGPF-1 exhibits significantly higher adsorption of C2H2 compared to C2H4 and CO2 at 298 K and 100 kPa, demonstrating exceptional selectivity towards 50/50 C2H2/CO2 and 1/99 C2H2/C2H4 to be 7.33 and 15.46. Breakthrough experiments confirm its effectiveness in separating C2H2 from C2H4/CO2 mixtures, with C2H4 saturation reached within 5 to 15 min, while C2H2 retention time at 298 K was as long as 26 min. Theoretical calculations have revealed that SGPF-1 exhibits electrostatic compatibility with C2H2 while repelling C2H4 and CO2 through an electrostatic exclusion mechanism. This highlights the importance of rational pore engineering in optimizing the electrostatic properties of adsorbents for high-efficiency multi-component separations. The research aims to advance gas separation technologies and improve the purity of acetylene, a valuable industrial raw material.

Influence of pore length non-uniformity on transport properties of random nanopore networks

The modeling of fluid transport in nanoporous materials has long attracted attention because of the numerous industrial applications of such materials, particularly in membrane-based separations, and others such as adsorptive gas separation and storage, catalysis, and the emerging area of nanofluidics. While effective medium theory has been widely used in modelling this transport, a critical approximation that all pores have the same length is commonly made, whose adequacy is unknown. Here we apply effective medium theory to a randomly overlapping capillary model having an inherent pore length distribution related to the pore radius distribution, and compare the network transport properties with those of the commonly used uniform pore length random network. We find that the consideration of nonuniform pore length distribution leads to significantly higher effective diffusivity and lower associated apparent tortuosity, mediated by the lower mean pore length of large pores due to their higher probability of overlap. The decrease in pore length with an increase in pore radius and the competing effects of adsorption and diffusion, lead to more complex behaviour of the transport properties with variation in temperature and relative standard deviation of the pore radius distribution. Our results clearly demonstrate the importance of considering nonuniformity of pore length, as the conventional uniform pore length approximation leads to significantly different and therefore misleading results.

Highly microporous activated carbons synthesized from sacrificial templating of melamine for CH4 and H2 storages and CH4/H2 adsorptive separation

Achieving carbon neutrality necessitates advancements in adsorbent-based gas storage technologies, particularly for maximizing the utilization of natural gas (CH4) and hydrogen (H2) as sustainable energy sources. Activated carbons, characterized by their high surface area, stability, and cost-effectiveness, emerge as promising candidates for CH4 and H2 storage applications. Here, we report highly microporous activated carbons prepared using sacrificial templating of melamine followed by Cs+ ion activation. The resulting activated carbon demonstrates exceptional microporous characteristics, boasting a significantly high micropore surface area (2311 m2/g) and micropore volume (1.070 cm3 g−1). These structural attributes translate into impressive CH4 (11.92 mmol/g at 298 K and 70 bar) and H2 (2.74 mmol/g at 298 K and 70 bar) storage capacities, underscoring its potential as a viable ambient temperature gas storage material. Furthermore, our evaluation extends to the performance of the activated carbon for adsorptive CH4/H2 separation. The activated carbon exhibits a notable CH4 working capacity (3.13 mmol/g at 298 K, 1–10 bar pressure swing) coupled with a moderate Ideal Adsorbed Solution Theory (IAST) selectivity (25). These findings highlight the suitability of the activated carbon for both CH4 and H2 storage applications, as well as the separation of H2 from CH4.

Dual-function CoNi-LDH hollow porous spheres for morphology-driven adsorptive removal and photo-oxidative degradation of anionic dyes

The layered double hydroxides (LDHs) emerged as a class of low-cost potential adsorbents for organic pollutant separation, whereas the deep study of organic dye separation regulated by LDH hollow morphology under ambient conditions is still lacking. To address this gap, ZIF-67, Bulk-CoNi-LDH, and HPS-CoNi-LDH materials of different morphology and porosity were synthesized and investigated in the dye separation process. Methyl orange (MO), congo-red (CR), methylene blue (MB), and rhodamine B (Rhb) dyes were selected as model dye pollutants. The spectroscopic and structural analysis reveals the HPS-CoNi-LDH exhibits less-aggregated 2D nanosheets, high BET surface area of 163.2 m2/g, large pore size of 12.29 nm, greater positive surface charges (27.5 mV), superior optical (2.18 eV), and charge-separation capabilities as compared to Bulk-CoNi-LDH, Which provides potential sites for adsorptive and photo-degradation for anionic dyes under natural sunlight. Therefore, it achieves a remarkable removal efficiency of 92.6% for methyl orange (15 ppm) with a superior kinetic rate of 3.0×10−2 min−1 within 90 min, outperforming Bulk-CoNi-LDH and ZIF-67 having removal efficiency of 71.7% and 40.8%, and kinetic rate of 1.35×10−2 and 0.5×10−2 min−1, respectively. Poor removal efficiency and kinetic by ZIF-67 was mainly due to its smaller pore size (1.16 nm) and surface-confined charges (6.13 mV). Additionally, HPS-CoNi-LDH exhibits superb selectivity (at a ppm level) and excellent recyclability under ambient conditions. The mechanism of photo-catalytic reaction is discussed. These results delineate the hollow morphological LDH structure could be a worthy candidate for selective wastewater treatment and useful for sustainable conditions, which points the way to other crucial anionic micropollutant remediation.

Zinc-cluster-based MOF with super selective separation adsorption catalyzes direct chemical conversion of CO2 from quasi-polluted air

The CO2 in the atmosphere has a serious impact on the human living environment. Direct utilization of the discharged CO2 to produce useful chemicals is challenging due to the practical presence of mixed compositions and low concentrations for CO2. Metal-organic frameworks (MOFs) with high internal surface areas, porosity and open metal site potentially possess superior adsorption separation capacity for CO2 gas, and on this basis, it can be used as a catalyst to achieve efficient chemical conversion of CO2. We demonstrate the synthesis and characterization of MOF ([Zn4O(ntba)2]n, MOF 1, H3ntba=4,4',4''-nitrilotribenzoic acid) with excellent selective adsorption properties from quasi- polluted air (O2, N2, CO2, CH4) and as heterogeneous catalysts for direct efficient CO2 chemical conversion. Detailed structural analysis reveals show that zinc ions behave multiple open metal sites and two coordination modes in the polyhedral zinc clusters building unit forming a 3D porous network by polyhedral zinc clusters building unit. Thanks to its structural features, at the 273 K and 100kPa, due to the ideal specific surface area and porosity, MOF 1 have ideal adsorption-separation performance for CO2, its values of adsorption and separation ratio are 75.7 cm3g−1, 373(CO2/N2), 79(CO2/O2), 13(CO2/CH4), respectively. The cycloaddition catalytic reaction investigations show that MOF 1 can be employed as a highly efficient catalyst for converting CO2 with a yield of 78 %. The result of this experiment offers the potential to directly utilize low-concentration and mixed CO2 while avoiding the economic and environmental costs of obtaining purified CO2 feeds tocks.

Graphene Incorporated Sugar Derived Carbon Aerogel for Pyridine Adsorption and Oil-Water Separation.

Herein, we have synthesized a three-dimensional and hydrophobic graphene incorporated carbon aerogel (G-SCA) derived from sugar. G-SCA is being used as a multifunctional sorbent material for removing various advanced water-soluble and insoluble pollutants. Initially, G-SCA is being explored for the adsorption of nitroarenes (nitrophenols, 3-nitroaniline), an insecticide (Phoskill), an antibiotic (ciprofloxacin), and a pharmaceutical drug precursor (pyridine). Later, the same G-SCA is also explored in the absorption of various protic and aprotic organic solvents, and oils (including crude oil, waste cooking oil, and waste engine oil), with excellent recyclability checked up to 10 cycles. Moreover, oil-water separation experiments are also being done in various industrial wastewater and seawater samples to support the real-life accessibility of the present approach. Large-scale applicability of G-SCA is also checked by performing crude oil-seawater separation experiments using a laboratory-scale prototype demonstrating the successful continuous recovery of crude oil.

A model for hindered diffusion in pores

Hindered diffusion is a longstanding interest to chemical engineers working in such fields as heterogeneous catalysis, adsorptive and biochemical separations, and environmental engineering. In this work, a novel and universal model unifying the pore diffusion and surface diffusion was deduced theoretically to account for the pore diffusion control or surface diffusion control in pores. Based on the model, a versatile restrictive factor expression was proposed to describe the correlation between the effective diffusivity and the ratio of molecular diameter to pore diameter. Various variations of restrictive factor versus the ratio of molecular diameter to pore diameter from reported literatures were interpreted better than previous restrictive factor equations. Especially, the restrictive factor with non-monotonic variations could not be explained with the reported restrictive factor equations, but interpreted well by equation in this work. Furthermore, the diffusion tortuosity was first proposed herein to account for the effect of molecule diffusion path on diffusion behavior in pores.

Photocatalytic Extraction of Uranium from Seawater Using Covalent Organic Framework Nanowires.

In the push to achieve net-zero emissions by 2050, nuclear power will play an essential role alongside renewable wind and solar power, and correspondingly global interest and investment in this well-established technology is accelerating. The uranium present in seawater could support nuclear power generation for centuries, but traditional adsorptive separation strategies have proven ineffective for the selective extraction of uranium from this vast resource. Here, we report the synthesis of nanowires of a triazine-linked two-dimensional covalent organic framework via a solvent modulation approach, which can be used to access nanowire external diameters ranging from 50 to 200 nm. The 100 nm nanowires are exceptionally promising for the capture of uranium(VI) via photocatalytic reduction. Under simulated sunlight and without the use of sacrificial agents, the nanowires achieve a uranium uptake of 10.9 g/g from a 100 ppm uranyl(VI) solution, which is the highest reported to date among materials studied for photo and electrocatalytic uranium capture. Significantly, these nanowires exhibit a uranium adsorption capacity of 34.5 mg/g after exposure to seawater under irradiation for 42 days, a record among all materials reported to date for uranium capture.

Regulating the Oxygen Vacancy on Bi2MoO6/Co3O4 Core‐Shell Nanocage Enables Highly Selective CO2 Photoreduction to CH4

AbstractPhotocatalytic CO2 reduction reaction (CO2RR) into high‐value‐added fuels has received significant attention, yet multiple electron and proton processes involved in CO2RR result in low selectivity. Herein, a strategy involving oxygen vacancies (Ovs)‐enriched Bi2MoO6 coated on ZIF‐67‐derived Co3O4 to construct well‐defined core‐shell nanocage is developed, which drives effective CO2 photoconversion to CH4 with nearly 100% selectivity and high apparent quantum efficiency of 2.5% at 420 nm in pure water under simulated irradiation. Theoretical calculations and experiments exhibit that the potential difference stemming from the built‐in electric field provides guarantee for CO2 reduction occurring on Bi2MoO6 and H2O oxidation set in Co3O4. Numerous exposed Bi2MoO6 with Ovs formed in Bi─O bond by ethylene glycol mediated approach promotes the CO2 adsorption and charge separation efficiency, which can optimize the reaction kinetics and thermodynamics, facilitating the hydrogenation of key intermediate *CO to generate CH4. This work provides a new strategy for controlled oxygen vacancy generation on photocatalysts to achieve high‐performance CO2 methanation.

Pore Chemistry and Architecture Control in Anionic Functional Ultramicroporous Materials for Record Dense Packing of Xenon.

Adsorptive separation of Xe and Kr is an industrially promising but challenging process because of their identical shape and similar physicochemical properties. Herein, we demonstrate a strategy through rationally designing the linkers of anionic functional ultramicroporous materials (FUMs) to finely regulate the pore chemistry and architecture, which creates unique stepped channels incorporating dense polar nanotraps to generate a larger effective pore space and enables dense packing of Xe. A new hydrolytically stable FUM (ZUL-530) was prepared, which for the first time achieves a Xe packing density exceeding the liquid Xe density at atmospheric conditions in metal-organic frameworks (MOFs) (based on experimental data), resulting in both excellent Xe uptake (2.55 mmol g-1 at 0.2 bar) and high IAST selectivity (20.5). GCMC and DFT-D calculations reveal the essential role of the stepped traps in the dense packing of Xe. Breakthrough experiments demonstrate remarkable productivities of both high-purity Kr (6.70 mmol g-1) and Xe (1.78 mmol g-1) for the Xe/Kr (20:80) mixture. In a model nuclear industry exhaust gas, ZUL-530 exhibits a top-class Xe dynamic capacity (28.8 mmol kg-1) for trace Xe, which proves it is one of the best candidates for Xe/Kr separation.

Efficient adsorptive separation of nitrotoluene isomers via a stable and low-cost metal–organic framework with descending affinity order of meta-/ortho-/para-isomers

Obtaining purified nitrotoluenes from their mixture is significant but challenging due to their similar molecular sizes and physical properties. To overcome this challenge, here we report a stable, inexpensive and green-synthesized aluminium-based metal–organic framework (MIL-160) to separate the nitrotoluene mixtures. The appropriate pore size and pore environment permitted MIL-160 to exhibit a rare meta-nitrotoluene (m-NT) preference and always maintain the meta- > ortho- > para-nitrotoluene (m- > o- > p-NT) adsorption order in dynamic breakthrough and pulse modes as well as batch-mode adsorption. Theoretical calculations revealed that the abundant H/O atoms in the confined nanospace provided strong binding sites for selectively capturing nitrotoluene isomers. Specifically, due to difference in shape matching, the strongest host–guest interactions occurred in m-NT@MIL-160, followed by o-NT@MIL-160, and last p-NT@MIL-160. Notably, breakthrough experiments confirmed that a variety of binary and ternary mixtures can be separated via continuous adsorption. The dynamic adsorption stage of ternary mixture directly produced 0.33 mmol g−1 of pure p-NT, and the eluent in the desorption stage contained a high content of m-NT. Additional dynamic adsorption model fitting results indicated that the outstanding dynamic separation performance was also achieved from kinetic factors. These results lay the foundation for the effective separation of nitrotoluene mixtures.

Hierarchically porous carbon foams coated with carbon nitride: Insights into adsorbents for pre-combustion and post-combustion CO2 separation

Adsorption is fundamental to many industrial processes, including separation of carbon dioxide from other gases in pre- or post-combustion gas mixtures. Adsorbents should have high capacity and selectivity, which are both intimately linked with surface area, pore size distribution, and surface energy. Porous carbons are cheap and scalable adsorbents, but greater understanding of how their textural properties and surface chemistry affects their performance is needed. Here, we investigate the effect of nitrogen doping on CO2 adsorption. Microporous carbon foams with large surface area (>2500 m2 g−1) and pore volume (1.6 cm3 g−1) are synthesized, then coated with varying amounts of carbon nitride (up to 17 at% nitrogen) to achieve high CO2 uptake (25.5 mmol g−1) and selectivity (CO2:N2 = 21), whilst also giving insights into the relationship between structure and function. At low pressure (relevant to post-combustion capture), moderate carbon nitride loading leads to enhanced uptake and selectivity by combining large ultramicropore volume with the introduction of Lewis base sites, leading to high isosteric heat of adsorption. Higher carbon nitride loading further increases selectivity but lowers uptake by blocking micropores. Conversely, at high pressure (relevant to pre-combustion capture) the uncoated carbon foam displays superior uptake, because mesoporosity is the dominant factor in this regime, rather than the presence of ultramicropores. Finally, the samples displayed excellent regeneration under repeated adsorption–desorption cycles, and breakthrough curves were measured. These results underscore the delicate balance required for optimal material design when applying porous carbon adsorbents to CO2 separation processes. Moving forward, improved adsorbents will contribute to the proliferation of carbon capture and storage (CCS) and carbon capture and utilisation (CCU) technologies, ultimately contributing reduced anthropogenic CO2 emissions.

Trifunctionalized Ionic Covalent Organic Framework-Engineered Mixed-Matrix Membranes for Rapid and High-Performance Adsorptive Separation of Charged Aqua Pollutants

Trifunctionalized Ionic Covalent Organic Framework-Engineered Mixed-Matrix Membranes for Rapid and High-Performance Adsorptive Separation of Charged Aqua Pollutants

Combined experimental and theoretical studies on adsorption characteristics of graphitic carbon nitride for flue gas molecules

Graphitic carbon nitride (g-C3N4) is a novel selective adsorbent for separation of Hg0 and Hg2+, which plays a pivotal role in mercury continuous emission monitoring systems (Hg-CEMS). However, some of the flue gas components may interfere with their binding characteristics with g-C3N4. This study employs the density functional theory (DFT) and experimental method to investigate the adsorption behavior of gas components on g-C3N4 and elucidates the intrinsic driving forces behind these interactions and assesses their impact on separation of Hg0 and HgCl2. The binding energies of H2O, SO2, CO2, NO, and O2 molecules on g-C3N4 are −0.575 eV, −0.530 eV, −0.309 eV, −0.246 eV, and −0.238 eV, respectively. The electronic structure and weak interaction analyses indicate that these interactions are primarily van der Waals forces caused by multi-atomic interactions. In contrast, the binding energy between HCl and g-C3N4 is −0.557 eV, primarily controlled by weak H-N covalent bonds. The co-adsorption results indicate that flue gas molecules exert negligible effects on the binding of HgCl2 to g-C3N4 because the changes in binding energy are within 0.15 eV. The experimental results verify that under practical operating conditions, the adsorption of H2O, HCl, SO2, CO2, NO, and O2 on g-C3N4 is below 0.1 %, demonstrating those components do not interfere with the separation of Hg0 and HgCl2 by g-C3N4, nor do they affect the regeneration performance of g-C3N4. This study provides new insights into the development and practical application of separation and conversion modules in Hg-CEMS technologies.

Stepwise tuning carbon slits at sub-angstrom scale for dynamical separation of hydrogen isotope

Heavier hydrogen isotope is indispensable for many applications such as isotope tracing and labeling, neutron scattering, and nuclear fusion reaction. Thus it calls for efficient hydrogen isotope separation. Cryogenic adsorptive separation is an energy-efficient way for deuterium/protium (D2/H2) separation, requiring nanopores with precisely tuned pore size and suitable geometry to induce the quantum sieving effect. Herein, we report on the stepwise tuned slit-shaped ultramicropores at sub-angstrom (Å) scale for highly efficient D2/H2 separation. The opening width of carbon nanoslits was precisely tuned by the devised thermal-induced molecularly imprinting method. The adsorbent with 4.0 Å centered nanoslits showed an excellent D2/H2 uptake ratio of 1.9 with a high D2 uptake of 10.1mmol/g at 40 K and 100 kPa. Column breakthrough experiments revealed a high D2/H2 selectivity of 10.1 at 40 K. It evidenced that the 4.0 Å centered slits enable an optimal balance between the barrier induced by zero-point energy and the adsorption potential at 40 K, thereby reaching a selectively quantized configurational diffusion of D2/H2. Programmed thermal desorption experiments indicated that a 0.1 Å alteration of the slit size enhanced the quantum sieving effect of D2/H2 by 180 %. These results would benefit the understanding of D2/H2 separation behavior, and the design principle may inspire other isotope separations.

Combining machine learning and molecular simulation to explore MOF materials that contribute to CF4/N2 separation

High-throughput molecular simulations and machine learning algorithms have been widely used to identify promising metal–organic frameworks for gas separation. However, most studies are limited to screening high-performance materials from existing databases, which fails to fully utilize the predictive function of machine learning. This paper combines genetic algorithms and high-throughput screening to deeply mine anion-pillared MOF (APMOF) performance feature relationships and predict high-performance materials that are not in the database. Considering the actual industrial conditions (CF4/N2 = 10/90), we chose the ratio of CF4:N2 = 1:9 to simulate the adsorption separation of gas mixtures of MOF materials at a temperature of 298 K and a pressure of 1 bar. First, the CF4/N2 separation properties of MOFs in the APMOF library were obtained based on molecular simulations. Then, the filtered data were coded according to the method of “building block classification − structural interval categorization”. Then, the machine learning algorithm was used for model training to obtain a high-precision model. Finally, the tangent adaptive genetic algorithm was used to recombine the genes of the materials, and the new MOF materials were successfully reverse-engineered. The study found that the pore-limit diameter of APMOFs is most conducive to the separation of CF4/N2 by MOFs when the pore-limit diameter of APMOFs is within two times the molecular dynamics diameter of CF4. 134 MOF materials were predicted to have CF4/N2 selectivities exceeding 46.30. The use of organic ligands such as 4,4′-bipyridyl or 1,4-bis(4-pyridyl)benzene (bpb) increases the likelihood of these materials being high-performance for CF4/N2 separation. The combination of computational screening methods and machine learning can expedite the design and development of new high-performance MOFs. This approach can also provide guidance for the synthetic direction and pattern of materials, which can assist experimentalists in their synthesis.

Application of physicochemical techniques to the removal of ammonia nitrogen from water: a systematic review.

Ammonia nitrogen is a common pollutant in water and soil, known for its biological toxicity and complex removal process. Traditional biological methods for removing ammonia nitrogen are often inefficient, especially under varying temperature conditions. This study reviews physicochemical techniques for the treatment and recovery of ammonia nitrogen from water. Key methods analyzed include ion exchange, adsorption, membrane separation, struvite precipitation, and advanced oxidation processes (AOPs). Findings indicate that these methods not only remove ammonia nitrogen but also allow for nitrogen recovery. Ion exchange, adsorption, and membrane separation are effective in separating ammonia nitrogen, while AOPs generate reactive species for efficient degradation. Struvite precipitation offers dual benefits of removal and resource recovery. Despite their advantages, these methods face challenges such as secondary pollution and high energy consumption. This paper highlights the development principles, current challenges, and future prospects of physicochemical techniques, emphasizing the need for integrated approaches to enhance ammonia nitrogen removal efficiency.

The CO Working Capacity of Ni-MOF-74 and Corresponding Operating Conditions for CO/N2 Adsorption Separation

The CO Working Capacity of Ni-MOF-74 and Corresponding Operating Conditions for CO/N₂ Adsorption Separation

Effects of Phosphorus Doping on Amorphous Boron Nitride's Chemical, Sorptive, Optoelectronic, and Photocatalytic Properties.

Amorphous porous boron nitride (BN) represents a versatile material platform with potential applications in adsorptive molecular separations and gas storage, as well as heterogeneous and photo-catalysis. Chemical doping can help tailor BN's sorptive, optoelectronic, and catalytic properties, eventually boosting its application performance. Phosphorus (P) represents an attractive dopant for amorphous BN as its electronic structure would allow the element to be incorporated into BN's structure, thereby impacting its adsorptive, optoelectronic, and catalytic activity properties, as a few studies suggest. Yet, a fundamental understanding is missing around the chemical environment(s) of P in P-doped BN, the effect of P-doping on the material features, and how doping varies with the synthesis route. Such a knowledge gap impedes the rational design of P-doped porous BN. Herein, we detail a strategy for the successful doping of P in BN (P-BN) using two different sources: phosphoric acid and an ionic liquid. We characterized the samples using analytical and spectroscopic tools and tested them for CO2 adsorption and photoreduction. Overall, we show that P forms P-N bonds in BN akin to those in phosphazene. P-doping introduces further chemical/structural defects in BN's structure, and hence more/more populated midgap states. The selection of P source affects the chemical, adsorptive, and optoelectronic properties, with phosphoric acid being the best option as it reacts more easily with the other precursors and does not contain C, hence leading to fewer reactions and C impurities. P-doping increases the ultramicropore volume and therefore CO2 uptake. It significantly shifts the optical absorption of BN into the visible and increases the charge carrier lifetimes. However, to ensure that these charges remain reactive toward CO2 photoreduction, additional materials modification strategies should be explored in future work. These strategies could include the use of surface cocatalysts that can decrease the kinetic barriers to driving this chemistry.