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Herein, mixed–metal nanocomposite catalysts with various compositions (CoFe2O4/xFe2O3; x = 0, 0.25, 0.50, 0.75 and 1) were successfully fabricated by a co–precipitation method. The composition and morphology of the catalyst were systematically characterized. The catalyst with the highest Co content (CoFe2O4), exhibited the greatest efficiency for the acid orange 7 (AO7) degradation via peroxymonosulfate (PMS) activation. The effects of several experimental parameters including pH, CoFe2O4 loading, and PMS dosage on AO7 degradation were studied, and the catalytic activity was found to increase with the mentioned parameters. Moreover, CoFe2O4 displayed adequate reusability and was able to degrade AO7 for at least four consecutive cycles. In addition, the total organic carbon (TOC) removal of CoFe2O4 was determined while the catalyst stability was observed from the metal leaching in the treated solution. Furthermore, the magnetism of CoFe2O4 provides facile separation of the catalyst from the treated solution. Sulfate radicals (SO4•–) were identified as the main reactive species responsible for AO7 degradation.

Herein, five N, S-co-doped carbocatalysts were prepared from different carbonaceous precursors, namely sawdust (SD), biochar (BC), carbon-nanotubes (CNTs), graphite (GP), and graphene oxide (GO) and compared. Generally, as the graphitization degree increased, the extent of N and S doping decreased, graphitic N configuration is preferred, and S configuration is unaltered. As peroxymonosulfate (PMS) activator for ciprofloxacin (CIP) removal, the catalytic performance was in order: NS-CNTs (0.037 min-1) > NS-BC (0.032 min-1) > NS-rGO (0.024 min-1) > NS-SD (0.010 min-1) > NS-GP (0.006 min-1), with the carbonaceous properties, rather than the heteroatoms content and textural properties, being the major factor affecting the catalytic performance. NS-CNTs was found to have the supreme catalytic activity due to its remarkable conductivity (3.38 S m-1) and defective sites (ID/IG = 1.28) with high anti-interference effect against organic and inorganic matter and varying water matrixes. The PMS activation pathway was dominated by singlet oxygen (1O2) generation and electron transfer regime between CIP and PMS activated complexes. The CIP degradation intermediates were identified, and a degradation pathway is proposed. Overall, this study provides a better understanding of the importance of selecting a suitable carbonaceous platform for heteroatoms doping to produce superior PMS activator for antibiotics decontamination. This work was supported by the Universiti Sains Malaysia, Research University Team (RUTeam) Grant Scheme (Grant Number: 1001/PJKIMIA/8580061).

In this study, graphitic carbon nitride (CN) decorated with carbon quantum dot (CQD) and bismuth oxychlorobromide (BiOCl

Herein, we report a detailed study on creating heterojunction between graphitic carbon nitride (g-C3N4) and bismuth phosphate (BiPO4), enhancing the unpaired free electron mobility. This leads to an accelerated photocatalysis of 2,4-dichlorophenols (2,4-DCPs) under sunlight irradiation. The heterojunction formation was efficaciously conducted via a modest thermal deposition technique. The function of g-C3N4 plays a significant role in generating free electrons under sunlight irradiation. Together, the generated electrons at the g-C3N4 conduction band (CB) are transferred and trapped by the BiPO4 to form active superoxide anion radicals (•O2-). These active radicals will be accountable for the photodegradation of 2,4-DCPs. The synthesized composite characteristics were methodically examined through several chemical and physical studies. Due to the inimitable features of both g-C3N4 and BiPO4, its heterojunction formation, 2.5wt% BiPO4/g-C3N4 achieved complete 2,4-DCP removal (100%) in 90 min under sunlight irradiation. This is due to the presence of g-C3N4 that enhanced electron mobility through the formation of heterojunctions that lengthens the electron-hole pairs' lifetime and maximizes the entire solar spectrum absorption to generate active electrons at the g-C3N4 conduction band. Thus, this formation significantly draws the attention for future environmental remediation, especially in enhancing the entire solar spectrum's harvesting.

In this study, chitosan/porous carbon composite (C-PC) modified in 1-Allyl-3-methyl imidazolium bromide [AMIM][Br] under airtight condition was prepared for the removal of Acid Blue-25 dye (AB-25) from aqueous medium. For comparison of adsorption efficiency of C-PC, chitosan-activated carbon composite (C-AC) was also prepared in 1% acetic acid. The adsorbents were characterised using SEM, EDX, XRD, BET, TGA and FTIR. The micrograph of C-PC revealed cavities and slightly rough surfaces dominated with similar sized and irregular shaped stone-like materials which differ from the precursors' micrograph. BET analysis revealed the domination of mesopores on the C-PC and C-AC surfaces, as the hydroxyl and amino group on C-PC are the main active sites for AB-25 dye uptake. The dye was better adsorbed onto C-PC at pH 2 and C-AC at pH 4. The adsorption capacity obtained for C-PC, C-AC, activated carbon (AC) and chitosan (CH) using Langmuir isotherm model are 3333.33 mg/g, 909.90 mg/g, 909.09 mg/g and 833.33 mg/g, respectively. The experimental data are well described by Langmuir and Fruendlich isotherms for adsorption of the dye onto C-PC, AC and CH. C-AC fitted into Langmuir isotherm only. The kinetics of the adsorption fitted into pseudo-second order indicating the possibility of chemical interactions in the adsorption process.

As caffeine (CAF) is extensively consumed as food additives and medication, CAF has been continuously released into aquatic environment, causing threats to ecology because of its high solubility and persistency. While cobalt sulfides have received increasing attention for activating monopersulfate (MPS), almost no studies have been conducted to investigate cobalt sulfides to degrade CAF. Thus, the aim of this study is to investigate cobalt sulfide for activating MPS to degrade CAF. Specifically, a unique cubic cluster of cobalt sulfide nanosheets (CoSNS) is developed through a simple sulfurization of cobaltic Prussian Blue Analogue (Co-PBA) (Co3[Co(CN)6]2) under very mild condition (25 °C) to convert Co-PBA to CoSNS. CoSNS could exhibit much higher catalytic activities than its precursor Co-PBA, and the benchmark catalyst of MPS activation, Co3O4, for activating MPS to degrade CAF in 45 min. Ea of CAF degradation (24.3 kJ/mol) by CoSNS+MPS is also significantly lower than many reported Ea values, validating that CoSNS is an advantageous and highly-efficient catalyst for MPS activation to degrade CAF. The activation mechanism of CoSNS towards MPS activation is also realized using electron spin resonance. Degradation pathway of CAF degradation by CoSNS+MPS is also investigated by mass spectrometry to provide insights into degradation behaviors.

Aerobic oxidation of 5-Hydroxymethylfurfural (HMF) to 2,5-Diformylfuran (DFF) using O2 gas represents a sustainable approach for valorization of lignocellulosic compounds. As manganese dioxide (MnO2) is validated as a useful oxidation catalyst and many crystalline forms of MnO2 exist, it is critical to explore how the crystalline structures of MnO2 influence their physical/chemical properties, which, in turn, determine catalytic activities of MnO2 crystals for HMF oxidation to DFF. In particular, six MnO2 crystals, α-MnO2, β-MnO2, γ-MnO2, δ-MnO2, e-MnO2, and λ-MnO2 are prepared and investigated for their catalytic activities for HMF oxidation to DFF. With different morphologies and crystalline structures, these MnO2 crystals possess very distinct surficial chemistry, redox capabilities, and textural properties, making these MnO2 exhibit different catalytic activities towards HMF conversion. Especially, β-MnO2 can produce much higher DFF per surface area than other MnO2 crystals. β-MnO2 could achieve the highest CHMF = 99% and YDFF = 97%, which are much higher than the reported values in literature, possibly because the surficial reactivity of β-MnO2 appears to be highest in comparison to other MnO2 crystals. Especially, β-MnO2 could exhibit YDFF > 90% over 5 cycles of reusability test, and maintain its crystalline structure, revealing its advantageous feature for aerobic oxidation of HMF to DFF. Through this study, the relationship between morphology, surface chemistry, and catalytic activity of MnO2 with different crystal forms is elucidated for providing scientific insights into design, application and development of MnO2-based materials for aerobic oxidation of bio-derived molecules to value-added products.

The ever-increasing quantity of greenhouse gases in the atmosphere can be attributed to the rapid increase in the world population as well as the expansion of globalization. Hence, achieving carbon neutrality by 2050 stands as a challenging task to accomplish. Global industrialization had necessitated the need to enhance the current production systems to reduce greenhouse gases emission, whilst promoting the capture of carbon dioxide from atmosphere. Hydrogen is often touted as the fuel of future via substituting fossil-based fuels. In this regard, renewable hydrogen happens to be a niche sector of novel technologies in achieving carbon neutrality. Microalgae-based biohydrogen technologies could be a sustainable and economical approach to produce hydrogen from a renewable source, while simultaneously promoting the absorption of carbon dioxide. This review highlights the current perspectives of biohydrogen production as an alternate source of energy. In addition, future challenges associated with biohydrogen production at large-scale application, storage and transportation are included. Key technologies in producing biohydrogen are finally described in building a carbon-neutral future.

The primary aim of this study is to develop an economical, stable, and effective heterogeneous catalyst for wastewater remediation via the Fenton oxidation process. For this purpose, Fe

In order to efficiently degrade ibuprofen (IBU) by peroxymonosulfate (PMS) activation, manganese cobalt oxide nanoparticles-decorated functionalized multi-walled carbon nanotubes (MnCo2O4/FCNTs) were prepared using a facile hydrothermal method. Comprehensive characterization of this PMS activator in multi-scale suggested that MnCo2O4 nanoparticles were uniformly decorated on FCNTs. The catalytic performance was systematical evaluated under various environmental conditions, including temperature, pH, and the presence of different common water matrix species (e.g., Cl-, HCO3-, and natural organic matter). The as-synthesized MnCo2O4/FCNTs demonstrated excellent catalytic activity with kapp ranging 0.285-0.327 min-1 under a wide pH range of 3-9 within 10 min, which achieved a complete removal of IBU and a mineralization rate higher than 90%. During oxidation process for stability and reusability test, recycled MnCo2O4/FCNTs was found durable with negligible leaching of metal ions from spent catalyst, exhibiting its high stability for PMS activation with merely slight decrease of kapp from 0.285 to 0.201 min-1 in the fourth cycle. Electron paramagnetic resonance analysis further confirmed that •OH, SO4•- and 1O2 were generated in the robust MnCo2O4/FCNTs-PMS system. Both radical and nonradical reactions were found to be responsible for the enhanced IBU degradation. Overall, this study sheds light on practical knowledge of IBU removal using MnCo2O4/FCNTs for PMS activation. publishedVersion

As sulfosalicylic acid (SUA) is extensively used as a pharmaceutical product, discharge of SUA into the environment becomes an emerging environmental issue because of its low bio-degradability. Thus, SO4 −-based advanced oxidation processes have been proposed for degrading SUA because of many advantages of SO4 −. As Oxone represents a dominant reagent for producing SO4 −, and Co is the most capable metal for activating Oxone to generate SO4 −, it is critical to develop an effective but easy-to-use Co-based catalysts for Oxone activation to degrade SUA. Herein, a 3D hierarchical catalyst is specially created by decorating Co3O4 nanocubes (NCs) on macroscale nitrogen-doped carbon form (NCF). This Co3O4-decorated NCF (CONCF) is free-standing, macroscale and even squeezable to exhibit interesting and versatile features. More importantly, CONCF consists of Co3O4 NCs evenly distributed on NCF without aggregation. The NCF not only serves as a support for Co3O4 NCs but also offers additional active sites to synergistically enhance catalytic activities towards Oxone activation. Therefore, CONCF exhibits a higher catalytic activity than the conventional Co3O4 nanoparticles for activating Oxone to fully eliminate SUA in 30 min with a rate constant of 0.142 min−1. CONCF exhibits a much lower Ea value of SUA degradation (35.2 kJ/mol) than reported values, and stable catalytic activities over multi-cyclic degradation of SUA. The mechanism of SUA degradation is also explored, and degradation intermediates of SUA degradation are identified to provide a possible pathway of SUA degradation. These features validate that CONCF is certainly a promising 3D hierarchical catalyst for enhanced Oxone activation to degrade SUA. The findings obtained here are also insightful to develop efficient heterogeneous Oxone-activating catalysts for eliminating emerging contaminants.

Four different tests showed the effectiveness of Azolla pinnata plant extracts against Aedes aegypti and Aedes albopictus mosquitoes. In the adulticidal test, there was a significant increase in mortality as test concentration increases and A. pinnata extracts showed LC50 and LC95 values of 2572.45 and 6100.74 ppm, respectively, against Ae. aegypti and LC50 and LC95 values of 2329.34 and 5315.86 ppm, respectively, against Ae. albopictus. The ovicidal test showed 100% eggs mortality for both species tested for all the concentrations tested at 1500 ppm, 1000 ppm, 500 ppm, 250 ppm and 125 ppm. Both tested samples of Ae. aegypti and Ae. albopictus did not lay any eggs in the plastic cups filled with the A. pinnata extract but instead opted to lay eggs in the plastic cups filled with water during the oviposition deterrence test. Similarly, the non-choice test of Ae. aegypti mosquitoes laid eggs on the sucrose solution meant for the nutrient source of the mosquitoes instead of in the plastic cup that was designed to facilitate oviposition filled with the extract. This clearly indicates the presence of bioactive compounds which are responsible in adulticidal and ovicidal activity in Aedes mosquitoes and at the same time inducing repellence towards the mosquitoes. The LC–MS results showed mainly three important chemical compounds from A. pinnata extracts such as 1-(O-alpha-D-glucopyranosyl)-(1,3R,25R)-hexacosanetriol, Pyridate and Nicotinamide N-oxide. All these chemicals have been used for various applications such as both emulsion and non-emulsion type of cosmetics, against mosquito vector such as Culex pipens and Anopheles spp. Finally, the overall view of these chemical components from A. pinnata extracts has shown the potential for developing natural product against dengue vectors.

As sulfate-radical (SR)-based advanced oxidation processes are increasingly implemented, Oxone has been frequently-used for generation of SR. While Co3O4 nanoparticle (NP) has been widely-accepted as a promising catalyst for activating Oxone, Co3O4 NPs tend to aggregate in water, losing their reactivity. Thus, many attempts have immobilized Co3O4 NPs on supports, especially carbonaceous substrates, because combination of Co NPs with carbon substrates offers synergistic effects for boosting catalytic activities. Moreover, carbon substrates doped with hetero-atoms (N and S) further increase electron transfer and reactivity. Therefore, it is even promising to immobilize Co NPs onto N/S-doped carbon (NSC) to form Co-embedded NSC (denoted as CoNSC) for enhancing Oxone activation. In this study, a convenient and facile technique is proposed to prepare such a CoNSC via a simple carbonization treatment of a coordination polymer of Co and trithiocyanuric acid (TTCA). The resulting CoNSC exhibits the sheet-like hexagonal morphology with the core-shell configuration, and Co NPs are well-embedded into the N/S-doped carbonaceous matrix, making it an advantageous heterogeneous catalyst for Oxone activation. As Azorubine S (ARS) decolorization is employed as a model reaction of Oxone activation, CoNSC exhibits a higher catalytic activity than pristine Co3O4 and NSC for Oxone activation to decolorize ARS. In comparison to the other reported catalysts, CoNSC also possesses a much lower Ea for ARS decolorization. CoNSC can be also reusable and stable for Oxone activation over multiple cycles without loss of catalytic activity. These features validate that CoNSC is a promising and useful Co-based catalyst for Oxone activation.

Impoverishing nutrients from wastewater via assimilation into microalgal biomass has gained footprint in bioremediation technologies. To ease the harvesting of mature microalgal biomass from effluent, this study proposed the employment of fluidized bed bioreactor to grow attached microalgal biomass onto polyurethane foam support material while bioremediating the N-rich real wastewater from chemical fertilizer manufacturing industry. The complete removals of all nitrogen species (NH4+-N, NO2−-N and NO3−-N) together with COD and total phosphorus were achieved at the optimum light intensity and CO2 concentration of 216 μmol/m2 s and 9.1 %, respectively, giving rise to the attached microalgal biomass productivity of 0.094 g/L/day. These performances were also found maintaining for at least 4 cycles of reiterative uses of spent polyurethane foam support material in similar fluidized bed bioreactor setup condition with every cycle being introduced with fresh N-rich real wastewater. The mechanism of attachment formations study predicted that the polysaccharides and proteins from microalgal extracellular polymeric substances had bridged the cells onto polyurethane foam support material during the initial colonization prior to populating and growing to cover the surfaces of support material. For biodiesel production, the extracted neutral lipid content of attached microalgal biomass was found to be four times higher than the suspended growth culture. From the transesterification process, about 97 %–98 % of attached microalgal lipid could be converted into fatty acid methyl esters (FAMEs) mixture. Interestingly, the degree of saturated fatty acids (SFA) in FAMEs was recorded increasing with the increase of cycles of reusing spent polyurethane foam support material. The presence of more SFA in FAMEs could overall enhance the oxidative stability and contribute to higher cetane number of produced biodiesel from facilely harvested attached microalgal biomass.

The progression of urban industrialization releases large quantities of heavy metals into water, resulting in the severe heavy metal contamination of the aquatic environment. Traditional methods for removing heavy metals from wastewater generally have varying removal efficiencies, whereas algae adsorption technology is a cost-effective and sustainable bioremediation technique. A green technology that immobilizes algae through a carrier to improve biosorbent’s stability and adsorption performance is immobilization technology. The purpose of this review is to study the optimization strategy of the immobilization of algae for the bioremediation of heavy metals and to comprehensively analyze immobilized algae technology in terms of sustainability. The analysis of the mechanism of heavy metal removal by immobilized algae and the parameters affecting the efficiency of the biosorbent, as well as the approach based on life cycle assessment and economic analysis, allowed the identification of the optimization of the adsorption performance of immobilized algae. This provides a theoretical basis for the practical application of algal bioremediation.

Black soldier fly larvae (BSFL) have been deployed to valorize various organic wastes. Nonetheless, its growth rate whilst being offered with waste activated sludge (WAS) is not promising, likely by virtue of the presence of extracellular polymeric substances' structure in WAS. In this work, the WAS were first thermally pre-treated under different treatment temperatures and durations before being administered as the feeding substrates for BSFL. The results showed the thermal pre-treatment could improve WAS palatability and subsequently, enhance the growth of BSFL especially after the pre-treatments at 75 °C and above. The highest larva weight gained was recorded at 2.16 mg/larva for the WAS sample being pre-treated at 90 °C and 16 h. Furthermore, the samples pre-treated above 75 °C also achieved higher degradation rates, indicating that the 75 °C was a threshold temperature to effectively hydrolyze the WAS. The changes of WAS characteristics, namely, (i) soluble chemical oxygen demand (SCOD), (ii) soluble carbohydrate, (iii) soluble protein, (iv) humic substances and (v) total soluble protein and humic substances, after the thermal pre-treatments were also studied in correlating with the BSFL growth. Accordingly, a model was successfully developed with the highest R

Zero valent iron-loaded biochar (Fe

As CeO2 is a useful catalyst for soot elimination, it is important to develop CeO2 with higher contact areas, and reactivities for efficient soot oxidation and catalytic soot oxidation are basically controlled by structures and surface properties of catalysts. Herein, a Ce-Metal organic framework (MOFs) consisting of Ce and benzene-1,3,5-tricarboxylic acid (H3BTC) is employed as the precursor as CeBTC exhibits a unique bar-like high-aspect-ratio morphology, which is then transformed into CeO2 with a nanoscale bar-like configuration. More importantly, this CeO2 nanobar (CeONB) possesses porou, and even hollow structures, as well as more oxygen vacancies, enabling CeONB to become a promising catalyst for soot oxidation. Thus, CeONB shows a much higher catalytic activity than commercial CeO2 nanoparticle (comCeO) for soot oxidation with a significantly lower ignition temperature (Tig). Moreover, while soot oxidation by comCeO leads to production of CO together with CO2, CeONB can completely convert soot to CO2. The tight contact mode also enables CeONB to exhibit a very low Tig of 310 °C, whereas the existence of NO also enhances the soot oxidation by CeONB to reduce the Tig. The mechanism of NO-assisted soot oxidation is also examined, and validated by DRIFTS to identify the formation and transformation of nitrogen-containing intermediates. CeONB is also recyclable over many consecutive cycles and maintained its high catalytic activity for soot oxidation. These results demonstrate that CeONB is a promising and easily prepared high-aspect-ratio Ce-based catalyst for soot oxidation.

In this study, N-doped porous carbons (N–doped PCs) were prepared from various biowastes by thermal annealing method under inert atmosphere and compared. Due to the differences in the textural characteristics and %w/w inorganic content, the choice of biowaste influenced the intrinsic (extent of N doping, % graphitic N) and extrinsic (specific surface area) properties of the resultant N-doped PC. The N–doped PCs were employed to activate peroxymonosulfate (PMS) for bisphenol A (BPA) removal. It was found that the N–doped PCs prepared from spent coffee ground (PC–SC) and saw dust, with higher at.% graphitic N (44–46 at.%) and specific surface area (>400 m2 g−1), performed significantly better (apparent rate constant, kapp = 0.072–0.087 min−1) than those prepared from banana peel, orange peel and dried leaves (kapp

Nitrogen and boron-co-doped graphene was synthesized through two-step thermal annealing (2sNBG) which was employed as a PMS activator to degrade sulfacetamide (SAM). The concentration of the main reactive functionalities (pyridinic N and substitutional B (BC3)) as well as catalytic activity of 2sNBGs were delicately maneuvered through tuning the thermal annealing temperatures. The catalytic performances of the doped graphene in this study followed the order of 2sNBG800 > 2sNBG900 > 2sNBG700 > 2sNBG600 > NG600 > 1sNBGs > BG800. 30.4 at.% N of h-BN (Nh-NB/Ntotal) and 32.8 at.% B of h-BN (Bh-NB/Btotal) were detected in the 1sNBG800, which hampered the catalytic oxidation of SAM via PMS activation by 1sNBG. Among all the 2sNBGs, 2sNBG800 (2sNBG prepared at 800 °C) possessed the highest level of N (13.8 at.%) and B (16.3 at.%), the highest content of pyridinic N (73.4 at.%, Npyridinic-N/Ntotal) and BC3 (43.4 at.%, BBC3/Btotal), the lowest B-C–O (56.6 at.% BC2O, BBC2O/Btotal) content and none of h-BN. 2sNBG800 performed best to activate PMS for catalytic oxidation of SAM. Both radical quenching experiment and DFT calculation revealed that the introduction of B into NG can facilitate the transition from a non-radical oxidation dominating in the NG/PMS system to the coexistence of non-radical and radical oxidation in the 2sNBG/PMS system. The synergistic coupling effect between pyridinic N and BC3 (bonding configuration of B-C-C-C-pyridinic N) was the main reason for the enhanced catalytic activity of 2sNBG800. The transformation of the amine group and subsequent mineralization can effectively minimize the hazardous potentials of sulfonamides to the environment. The SAM degradation was negligibly influenced by NO3− in the 2sNBG800/PMS/SAM system, while Cl− and humic acid led to 33% and 64% decrease in kapp, respectively. The adsorbed intermediates mainly accounted for the deactivation of 2sNBG. This study provides an insight into the function of different N-B bonding configurations in NBG for metal-free catalytic oxidation. Ministry of Education (MOE) This research is supported by Ministry of Education, Singapore, under the Academic Research Grant RG96/16. X. D. appreciate the partial support from Open Research Projects of State Key Laboratory (SKL-ChE-16C05 and QAK201808).

In this work, nano-bimetallic Co/Fe oxides with different stoichiometric Co/Fe ratios were prepared using a novel one-step solution combustion method. The nano-bimetallic Co/Fe oxides were used for sulfamethoxazole (SMX) degradation via peroxymonosulfate (PMS) activation. The stoichiometric efficiencies of the as-prepared nano-bimetallic catalysts were calculated and compared for the first time. The radical generation was identified by electron paramagnetic resonance (EPR) as well as chemical quenching experiments, in which different scavengers were used and compared. The catalytic PMS activation mechanism in the presence of catalyst was examined by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results showed that besides SO4•- and •OH, •OOH was also detected in the PMS/CoFeO2.5 system. Meanwhile, in addition to the previously proposed radical oxidation pathway, the results showed that SMX degradation also involved a non-radical oxidation, which could be verified by the degradation experiment without catalyst as well as the detection of 1O2. In the PMS activation process, cobalt functioned as the active site on CoFeO2.5 while Fe oxide functioned as the adsorption site. The electron transfer mechanism was proposed based on the XPS and metal leaching results. Additionally, via the detection of transformation products, different SMX transformation pathways involving nitration, hydroxylation and hydrolysis in the PMS/CoFeO2.5 system were proposed. Accepted version

Phenolic compounds such as phenol, bisphenol A, 2,4-dichlorophenol, 2,4-dinitrophenol, 4-chlorophenol and 4-nitrophenol are well known to be highly detrimental to both human and living beings. Thus, it is of critical importance that suitable remediation technologies are developed to effectively remove phenolic compounds from aqueous solutions. Biodegradation utilizing enzymatic technologies is a promising biotechnological solution to sustainably address the pollution in the aquatic environment as caused by phenolic compounds under a defined environmentally optimized strategy and thus should be investigated in great detail. This review aims to present the latest developments in the employment of immobilized laccase for the degradation of phenolic compounds in water. The review first succinctly delineates the fundamentals of biological enzyme degradation along with a critical discussion on the myriad types of laccase immobilization techniques, which include physical adsorption, ionic adsorption, covalent binding, entrapment, and self-immobilization. Then, this review presents the major properties of immobilized laccase, namely pH stability, thermal stability, reusability, and storage stability, as well as the degradation efficiencies and associated kinetic parameters. In addition, the optimization of the immobilized enzyme, specifically on laccase immobilization methods and multi-enzyme system are critically discussed. Finally, pertinent future perspectives are elucidated in order to significantly advance the developments of this research field to a higher level.

Herein, we report a detailed study on creating heterojunction between graphitic carbon nitride (g-C