To mitigatethe aforementioned global environmental issues, the concept of carbon capture andstorage is crucial in addressing the necessity for carbon peaking and carbon neutrality.The buildup of volatile fatty acids during anaerobic fermentation is a primary factorcontributing to the suboptimal performance or outright failure of anaerobic digestionsystems. In response to the pressing demand for volatile organic acid recovery andhigh-value conversion, we primarily outlined the sources, recovery techniques, adsorptionmaterials, and methods for high-value conversion of volatile fatty acids. The methodsof adsorbing volatile acetic acid were presented, encompassing adsorption materials,mechanisms, and interfacial modifications of the adsorbent. Furthermore, drawingfrom recent research advancements, we have synthesized the high-value conversiontechniques for volatile fatty acids and evaluated the research challenges and futureprospects in this domain.

Glyphosate,which is one of the most widely used organophosphorus herbicides, poses athreat to the surrounding water environment. Traditional adsorbents weredepicted to have poor capacities to eliminate it. CeO₂ embraces the potentialto adsorb glyphosate efficiently. However, suitable carbonaceous composites were necessary to beemployed as its support. In this paper, water hyacinth was used as theprecursor to prepare CeO₂-loadedbiochar (CeO₂/WHBC),which was employed to remove glyphosate from the aqueous solution viaadsorption. The results showed that CeO₂/WHBC-3 illustrated the best adsorptionperformance for glyphosate with the capacity of 126.3 mg·g, which was preparedwith per mmol CeO₂ loaded of 0.2 g WHCB. Static adsorption experimentsdemonstrated that glyphosate adsorption at different solution pH valuesfollowed the Langmuir isotherm model and quasi-second order kinetic model,indicating that the adsorption was monolayer adsorption and that the adsorbent'ssurface active sites primarily controlled the rate. Coexisting ion interferenceexperiments showed that common cations (K⁺, Na⁺, Ca²⁺, Mg²⁺) and anions (Cl^-, NO₃^-, SO₄^2-) both promotedglyphosate adsorption on the CeO₂/WHBC-3 surface. Moreover, the prepared sorbent maintaineda high adsorption capacity after five adsorption-desorption cycles. Dynamicadsorption experiments showed that the CeO₂/WHBC-3 packed column could efficientlyremove glyphosate from aqueous solutions, even at high concentrations and fastflow rates. Zeta potentials and XPS analysis revealed that the adsorptionmechanism of CeO₂/WHBC-3for glyphosate is mainly through electrostatic adsorption and metalcomplexation.

Phenolicpollutants in water bodies pose a huge threat to human health and environmentalsafety. In this paper, a hydrophobicity-enhanced magnetic C-SiO₂/MPG composite wasprepared by a two-step method to remove bisphenol A (BPA)and 2,6-dichlorophenol(2,6-DCP), typical phenolic trace pollutants in livestock wastewater andnatural water bodies. The results of pH gradient experiments showed that C-SiO₂/MPG showed a stable removal effect onBPA in the pH range of 2-11. The adsorption of2,6-DCP by C-SiO₂/MPGpeaked at pH = 2, while the adsorption of 2,6-DCPby C-SiO₂/MPGwas severely inhibited under alkaline conditions. The PSO kinetic model and theLangmuir isotherm model can better describe the adsorption process of BPA and2,6-DCP on C-SiO₂/MPG,indicating that the monolayer chemical adsorption has a rate-controlling step.With the Langmuir equation fitting, the maximum adsorption capacity of C-SiO₂/MPG for BPA and2,6-DCP at 298 K was calculated to be 561.79 mg/g and 531.91 mg/g,respectively. The results of adsorption thermodynamics indicated that theadsorption of BPA and 2,6-DCP on C-SiO₂/MPG was spontaneous, accompanied by aprocess of entropy decrease. C-SiO₂/MPG showed good environmental resistance and repeated usestability for BPA and 2,6-DCP in electrolyte ion interference, actual watersamples and cycle experiments. Mechanism analysis showed that the adsorption ofBPA and 2,6-DCP on C-SiO₂/MPGwas mainly controlled by hydrogen bonding and hydrophobic interactions. Thisstudy designed an efficient adsorbent for phenolic pollutants that can be usedin actual wastewater and broadened the resource utilization of industrial wastephosphogypsm.

Thisstudy presents a chemo-microbial cascade process for the upcycling of wastepoly(ethylene terephthalate) (PET) into valuable compound 2,4-pyridine dicarboxylic acid (2,4-PDCA).Initially, waste PET undergoes efficient hydrolysis to terephthalic acid (TPA)with a high yield of 92.36%, catalyzed by p-toluenesulfonic acid (PTSA). The acid catalyst exhibitsexcellent reusability, maintaining activity over five cycles. Subsequently, aone-pot, two-step whole-cell conversion system utilizing genetically modified Escherichia coli strains (E. coli PCA and E. coli 2,4-PDCA) converts thegenerated TPA into 2,4-PDCA. By integrating the PET hydrolysis module with the2,4-PDCA biosynthesis module, the study achieves an impressive overallefficiency of 94.01% in converting challenging PET waste into valuable2,4-PDCA. Our research presents a rational design strategy for PET upcyclingand 2,4-PDCA synthesis methods. This research provides a systematic approach toPET upcycling, demonstrating its feasibility and potential for industrialapplication.

Herbal medicine plays animportant role in modern medicine and separation of the active ingredients fromherbal medicine is vital for convenient and safe usage. Paeonol andpaeonoflorin are the active ingredients in the widely used herbal medicine ofmoutan bark. In this study, the composite of graphene oxide-Fe₃O₄ nanoparticles (GO-Fe₃O₄) was synthesized and used as a magneticabsorbent to extract paeonol and paeonoflorin from the herbal medicine ofmoutan bark. The adsorption of paeonol and paeoniflorin on GO-Fe₃O₄ rapidly reached equilibrium (within 10 min) due to the high absorptioncapability of GO. Thermodynamics and kinetics for the absorption process werestudied. The optimal condition for the elution of the target compound from GO-Fe₃O₄ was the use of 2 mL of a mixed solvent (methanol and dichloromethane, 1:1 byvolume) with 0.2% formic acid for 5 min. The GO-Fe₃O₄ adsorbent possesses the advantages of rapid adsorption and convenientseparation. GO-Fe₃O₄ can be used over 6 times withoutlosing absorbing capacity. This method is efficient, convenient and rapid, thuspossesses a high potential for the separation of active ingredients from herbalmedicine.

Ammoniagas (NH₃) is a notorious malodorous pollutant released mainly inagriculture and industry. With the increasing demand for ammonia, environmentalpollution caused by ammonia discharge has seriously threatened human health andsafety. Due to the discrete emission and low concentration of NH₃,photocatalytic oxidation is an economical and efficient treatment strategy. TiO₂,as a common photocatalyst, has been widely used by researchers for thephotocatalytic removal of NH₃. In addition, surface modification,element doping, semiconductor recombination and metal loading are used toimprove the utilization rate of solar energy and carrier of TiO₂ soas to find a catalyst with high efficiency and high N₂ selectivity.Further, at present, there are three main removal mechanisms of NH₃ photocatalytic oxidation: ·NH₂ mechanism, iSCR mechanism and N₂H₄ mechanism. Among them, N₂H₄ mechanism is expected to bethe main removal path of NH₃ photocatalytic oxidation in the futurebecause the removal process does not involve NO_x and nitrate. Thisreview summarizes recent studies on the photocatalytic oxidation of NH₃,focusing primarily on NH₃ removal efficiency, N₂ selectivity, and the underlyingremoval mechanisms. Additionally, the potential future applications of NH₃photocatalytic oxidation are discussed.