Pyrolysis bio-oil was used to partially substitute for phenol in reacting with formaldehyde for the production of bio-oil phenol formaldehyde plywood (BPFP) panels, with the phenol substitution ratio being 20%, 40%, or 60%. Emissions of formaldehyde and volatile organic compounds (VOCs) from the BPFP panels were studied using solid-phase micro-extraction (SPME) followed by headspace gas chromatography/mass spectrometry (GC/MS), and were compared to those from the phenol formaldehyde plywood (PFP) panels. The sources for VOCs were analyzed, and the health risks associated with the BPFP were examined. Results showed that at 80 °C: (1) Formaldehyde emissions from the BPFP panels were increased to about 4 times that of PFP; (2) VOCs emissions were significantly reduced by up to 84.9% mainly due to the greatly reduced phenol emissions, although the total number of VOCs was increased from 20 to 35; (3) BPFP presents greatly increased carcinogenic and non-carcinogenic health risks because of its much stronger emissions of formaldehyde, N,N-dimethylformamide, benzofuran, furfural, and many chemicals from the bio-oil. It is highly advisable that the health risks are properly taken care of before the wide application of BPFP, or similar bio-oil based engineered wood products.

Norfloxacin (NOR) is a persistent organic pollutant and can be effectively removed from effluent by adsorption of biochar. However, the presence of other emerging contaminants, such as surfactants, will potentially alter adsorption performance of norfloxacin by biochar and the molecular-scale mechanisms of the interaction between surfactants and biochar remain poorly understood. In this study, adsorption of norfloxacin on magnetic biochar prepared with iron-containing furfural residue (FRMB) in the presence or absence of anionic surfactants was investigated. The adsorption of NOR was significantly affected by the initial pH and anionic surfactants-sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS). In the presence of SDS and SDBS, the maximum sorption capacities of NOR were 2.33 and 1.97 times higher than that in the absence of surfactants, reached to 698.6 mg g⁻¹ and 589.9 mg g⁻¹, respectively. The optimal pH condition which was 4 indicated that electrostatic adsorption played a decisive role in the adsorption process after introduction of SDS/SDBS. The adsorption data were fitted well by the Elovich model and Freundlich model at the optimal conditions in which both SDS and SDBS were hemimicelle (0.8 mM SDS or 0.4 mM SDBS), indicating surface heterogeneity of FRMB and the adsorption mechanism was related to the assembly of surfactants on biochar. FTIR results showed that FRMB and SDS/SDBS interacted through hydrophobic action, and more complex or aggregates were formed between the NOR and biochar/SDS/SDBS. This work highlights the synergistic enhancement effects of tested surfactants on the removal of NOR by magnetic biochar from aqueous systems.

The botanical substances constitute valuable alternatives to synthetic insecticides. In the last decades, numerous substances of natural origin have been tested against stored-product insects, mostly as fumigants or for contact toxicity, while there is limited knowledge on the efficacy of plant secondary metabolites if used as grain protectants. In the present study, we evaluated the lethal activity of 2-undecanone, acetic acid, trans-anethole, furfural, (E)-2-decenal and (E, E)-2,4-decadienal as wheat protectants for the management of larvae and adults of two important storage pests, Tenebrio molitor (Coleoptera: Tenebrionidae) and Trogoderma granarium (Coleoptera: Dermestidae). 2-undecanone caused 98.9% mortality to the exposed T. molitor adults at 1000 μl/kg wheat 7 days post-exposure, while acetic acid and furfural followed providing 94.4% and 92.2% mortality respectively. 2-Undecanone and (E)-2-decenal caused the highest mortalities to T. molitor larvae (i.e., 87.8% and 80.0% respectively) exposed to 1000 μl/kg wheat for 7 days. All T. granarium adults were dead at 1000 μl (E)-2-decenal or acetic acid/kg wheat 5 or 7 days post-exposure respectively. Complete (100%) mortality was assessed for larvae exposed to (E, E)-2,4-decadienal and (E)-2-decenal at 1000 μl/kg wheat after 4 and 6 days respectively. Our findings report for the first time that 2-undecanone, (E)-2-decenal, and (E, E)-2,4-decadienal are effective new candidate control agents of different developmental stages of T. molitor and T. granarium.

Three-dimensional carbon aerogel (CA800) was prepared from waste corrugated cardboard (WCC) by the procedure of slurrying, solvent replacement, drying, and carbonization in turn, and the product was explored as an all-in-one evaporator for solar steam generation without bulk water. Carbonization of the precursor was investigated using thermogravimetric analyzer coupled with Fourier transform infrared spectrometer. Results showed that CO₂, CO, furfural, and levoglucosan were released during pyrolysis of WCC within the range of 300 to 390 °C, while polymerization of newly formed char between 390 and 580 °C mainly resulted in the formation of CO₂ and CO. Both pyrolysis and polymerization reactions can be described by diffusion-controlled mechanisms, and the activation energies were 155.62 and 11.17 kJ mol⁻¹, respectively. CA800 possessed a BET surface area of 210 m² g⁻¹. Light can be effectively absorbed and converted into heat by CA800, and its surface temperature achieving 73 °C under 1 kW m⁻² irradiation. CA800 had outstanding wettability due to the presence of hydrophilic minerals in carbon matrix, and it was able to store as much as 15 times its own weight in water due to its abundant interconnected channels and hierarchical nanopores. Solar-driven water evaporation rate over CA800 achieved 1.72 kg m⁻² (normalized to projection area), which was nearly 6 times higher than the value achieved by the bare water system. The photothermal conversion efficiency was calculated to be 118 %, and the overestimated efficiency was caused by the environmental energy gained by the cold evaporation surface of CA800.

Biochars from Chinese medicine material residues and furfural residues at 300–600 °C (MBC300–MBC600 and FBC300–FBC600) were used as adsorbents for removing tetracycline (TC) from water. The influence of pH and co-existing of cations or low molecular weight organic acids (LMWOAs) was investigated on TC adsorption. Further, the bulk biochars were treated by ball milling into sub-micron particles, and their properties and adsorption performance toward TC were also characterized. For pristine biochars, TC adsorption was nonlinear and heterogeneous. Heterogeneity of biochars resulted in multiple sorption mechanisms, including H-bonding, π-π interaction, and pore filling. FBC300 and FBC600 had maximum sorption at pH 5–7. Electrostatic repulsion of positively charged biochar surfaces with TCH₃⁺ at pH < 3 or negatively charged biochar surfaces with TCH⁻ and/or TC²⁻ at pH > 7 was not favorable for TC removal. TC sorption decreased with increasing Na⁺ concentrations from 0 to 0.1 mol/L, and bivalent cations (Ca²⁺ and Mg²⁺) showed greater inhibiting effect relative to monovalent ones (Na⁺ and K⁺). The LMWOAs could combine with co-existing cations, thus reducing the inhibitory effect of cations and improving TC sorption. The ball milling caused remarkable size reduction of biochar particles, thus exposing more active surfaces to capture more TC molecules from water. This study provided low-cost and high-efficiency biochar absorbents to remove antibiotics from water and will benefit for understanding the relationship between TC sorption characteristics/mechanisms and biochar properties.

Furanic and phenolic compounds are problematic compounds resulting from the pretreatment of lignocellulosic biomass for biofuel production. Microbial electrolysis cell (MEC) is a promising technology to convert furanic and phenolic compounds to renewable H₂. The objective of the research presented here was to elucidate the processes and electron equivalents flow during the conversion of two furanic (furfural, FF; 5-hydroxymethyl furfural, HMF) and three phenolic (syringic acid, SA; vanillic acid, VA; 4-hydroxybenzoic acid, HBA) compounds in the MEC bioanode. Cyclic voltammograms of the bioanode demonstrated that purely electrochemical reactions in the biofilm attached to the electrode were negligible. Instead, microbial reactions related to the biotransformation of the five parent compounds (i.e., fermentation followed by exoelectrogenesis) were the primary processes resulting in the electron equivalents flow in the MEC bioanode. A mass-based framework of substrate utilization and electron flow was developed to quantify the distribution of the electron equivalents among the bioanode processes, including biomass growth for each of the five parent compounds. Using input parameters of anode efficiency and biomass observed yield coefficients, it was estimated that more than 50% of the SA, FF, and HMF electron equivalents were converted to current. In contrast, only 12 and 9% of VA and HBA electron equivalents, respectively, resulted in current production, while 76 and 79% remained as fermentation end products not further utilized in exoelectrogenesis. For all five compounds, it was estimated that 10% of the initially added electron equivalents were used for fermentative biomass synthesis, while 2 to 13% were used for exoelectrogenic biomass synthesis. The proposed mass-based framework provides a foundation for the simulation of bioanode processes to guide the optimization of MECs converting biomass-derived waste streams to renewable H₂.

Composition of three types of honey (mixed forest honey and monofloral—black locust and rapeseed honeys) originated from the vicinity of an industrial town (Košice, Slovak Republic) was compared. Higher content of minerals including toxic metals in forest honey (1358.6 ng Ni/g, 85.6 ng Pb/g, and 52.4 ng Cd/g) than in rapeseed and black locust honeys confirmed that botanical origin rather than the distance for eventual source of pollution (steel factory) affects metal deposition. Benzoic acid derivatives were typically more accumulated in forest but cinnamic acid derivatives and some flavonoids in rapeseed honey (in free and/or glycoside-bound fraction). In terms of quantity, p-hydroxybenzoic and p-coumaric acids were mainly abundant. Total phenols, thiols, and proteins were abundant in forest honey. Some metals and phenols contributed to separation of honeys based on principal component analysis (PCA). Native amount of 5-(hydroxymethyl)furfural was not related to honey type (~11 μg/g) and was elevated after strong acid hydrolysis (200–350 μg/g) but it did not interfere with the assay of phenols by Folin-Ciocalteu reagent. This is the first report of metals and metabolites in the same study, and data are discussed with available literature. We conclude that black locust (acacia) honey is the most suitable for daily use and that central European monofloral honeys contain lower amounts of toxic metals in comparison with other geographical regions.

The photocatalytic degradation of furfural in aqueous solution was investigated using N-doped titanium dioxide nanoparticles under sunlight and ultraviolet radiation (N-TiO₂/Sun and N-TiO₂/UV) in a lab-scale batch photoreactor. The N-TiO₂ nanoparticles prepared using a sol-gel method were characterized using XRD, X-ray photoelectron spectroscopy (XPS), and SEM analyses. Using HPLC to monitor the furfural concentration, the effect of catalyst dosage, contact time, initial solution pH, initial furfural concentration, and sunlight or ultraviolet radiation on the degradation efficiency was studied. The efficiency of furfural removal was found to increase with increased reaction time, nanoparticle loading, and pH for both processes, whereas the efficiency decreased with increased furfural concentration. The maximum removal efficiencies for the N-TiO₂/UV and N-TiO₂/Sun processes were 97 and 78 %, respectively, whereas the mean removal efficiencies were 80.71 ± 2.08 % and 62.85 ± 2.41 %, respectively. In general, the degradation and elimination rate of furfural using the N-TiO₂/UV process was higher than that using the N-TiO₂/Sun process.

In this study, thermochemical degradation of furfural by sulfate radical has been investigated to find the best-operating conditions. For this purpose, the response surface methodology (RSM) based on central composite design (CCD) was applied to optimize the five independent variables of thermally activated persulfate (TAP)/nZVI oxidation process including pH, PS concentration, furfural concentration, nZVI dosage, and heat. The ANOVA results (“P > F value” < 0.0001 and [Formula: see text] = 0.9701) showed the obtained quadratic model is acceptable to predict furfural removal. Based on the reduced quadratic model PS concentration, nZVI dosage, and heat revealed the positive effects on removal efficiency, while pH and furfural concentration had a negative effect. Accordingly, 98.4% of furfural could be removed within 60 min of reaction under the optimum conditions: pH 5.26, PS concentration of 20.52 mM, furfural concentration of 84.32 mg/L, nZVI dosage of 1.15 mg/L, and a temperature of 79 °C. In such circumstances, the furfural removal efficiency for TAP, PS/nZVI, PS, and nZVI was 94.5, 9, 3, and 2%, respectively. Therefore, based on the synergy index (SI) values, the combination of PS, nZVI, and heat can lead to a synergistic effect in the performance of the thermochemical process.