To achieve the high-value utilization of furfural residue (FR), this study innovatively employed a phenol-ultrapure water mixture to liquefy the entire components of FR, obtaining liquefied products (FRP) for the synthesis of modified phenolic resin (FRPF). The physicochemical properties of FRPF resin were systematically evaluated, and its structure and thermal performance were characterized using SEM, FT-IR, GPC, TG, and DSC. The results demonstrated that: 1) Under optimized conditions (20 % substitution rate, 170 degrees C liquefaction temperature, 2.5 h liquefaction time, and 15 wt% catalyst dosage), the FRPF resin exhibited a wet bond strength of 1.39 MPa and a formaldehyde emission of 1.326 mg/L, indicating its potential as an exterior-grade structural adhesive; 2) The FT-IR spectrum of FRPF resin was similar to that of pure phenolic resin (PF), suggesting analogous structures. However, condensation reactions between FRP molecules resulted in a broader molecular weight distribution and higher Z-average molecular weight. Additionally, the presence of liquefaction residues and sodium sulfate crystals on the resin surface collectively contributed to reduced bond performance; 3) Compared with PF resin, FRPF resin exhibited superior thermal stability. However, its curing onset temperature decreased from 39.55 degrees C to 35.84 degrees C, the peak temperature decreased from 55.31 degrees C to 53.19 degrees C, and the termination temperature increased from 67.68 degrees C to 79.63 degrees C, indicating an earlier initiation but slower reaction progress. This characteristic necessitates longer hot-pressing cycles and higher energy consumption in wood-based panel production. Overall, FRPF resin demonstrates potential feasibility for replacing PF resin.

Agricultural waste is an economically and environmentally beneficial precursor material for the development of activated carbon (AC) due to its low price, wide sources, and large production scale. This makes it a crucial field for agricultural waste treatment and AC development. This paper reviews the research progress of agricultural waste-based activated carbon (AWAC), including the sources and characteristics of agricultural waste, and the effects of raw material characteristics and activation conditions on the performance of AWAC. It analyzes the advantages and disadvantages of various preparation methods of AWAC. Additionally, it explains the research status of AWAC in wastewater treatment, gas adsorption, catalyst carrier, and energy carrier. Finally, this paper summarizes the advantages and limitations of using agricultural wastes as raw materials for AC, and provides a prospect for raw material development, process optimization, and application expansion, taking into account the shortcomings of current research.

This study focused on measuring the concentration of formaldehyde in furniture markets, malls, hotels, and restaurants in Guilin, Liuzhou, and Nanning in Guangxi, China. Correlations between the indoor formaldehyde concentration and temperature, humidity, and air change rate were also obtained. The sixty sampled public places selected for this study represented the typical public indoor environment in Guangxi. The percentages of measured formaldehyde concentrations exceeding the standard (0.1 mg m−3) in furniture markets, malls, and hotels were 94

Water pollution causes serious harm to aquatic plants and human health, which is an urgent problem in the world. In this paper, sugarcane leaf-based activated carbon (PSLAC and NiPSLAC) was prepared with sugarcane leaves as raw material and NH4H2PO4 and Ni(NO3)(2)/NH4H2PO4 as activators, respectively, which was applied to the adsorption of auramine in dyeing wastewater. At the same time, the water consumption of the sample preparation process was studied. X-ray diffraction (XRD), scanning electron microscope (SEM), thermogravimetric analysis (TG-DTG), fourier transform infrared spectrometer (FTIR), and Brunauer-Emmett-Teller (BET) were used to investigate the physicochemical properties of the samples. The water consumption of the NiPSLAC sample during the preparation process was 213.15 mL/g, which was 4.93%, 91.05%, 89.09%, 85.58%, and 54.18% of the NH4H2PO4, NaOH, KOH, K2CO3, and H3PO4 activated samples, respectively. The specific surface area and pore volume of the NiPSLAC sample were 1386.20 m(2)/g and 1.53 cm(3)/g, which were 410.57 m(2)/g and 0.46 cm(3)/g higher than the PSLAC sample, respectively. Compared with the PSLAC sample, the NiPSLAC sample had a higher graphitization degree and richer surface functional groups. Therefore, the NiPSLAC sample showed a higher adsorption capacity for auramine, reaching 164 mg/g, which was 1.12 times that of PSLAC, and the pseudo-second-order kinetic model and the Langmuir isotherm model could describe the adsorption process. This study provides a novel and advanced idea for developing a high-quality adsorbent for the removal of dyeing wastewater.

Formaldehyde (HCHO) is one of the major air pollutants, and its effective removal at room temperature has proven to be a great challenge. In this study, an Ag/Mn/CeO2 catalyst for the catalytic oxidation of low-concentration HCHO at room temperature was prepared by a hydrothermal-calcination method. The removal performance of the Ag/Mn/CeO2 catalyst for HCHO was systematically studied, and its surface chemical properties and microstructure were analyzed. The incorporation of Ag did not change the mesoporous structure of the Mn/CeO2 catalyst but reduced the pore size and specific surface area. The Ag species included metallic Ag as the main component and part of Ag+. The well-dispersed Ag species on the catalyst provided sufficient active sites for the catalytic oxidation of HCHO. The more the Ag active sites, the more the lattice defects and oxygen vacancies generated from the interaction of Ag with Mn/CeO2. Precisely because of this, the Ag/Mn/CeO2 catalyst exhibited high catalytic activity for HCHO at room temperature with a removal efficiency of 96.76% within 22 h, which is 22.91% higher than that of the Mn/CeO2 catalyst. Moreover, the Ag/Mn/CeO2 catalyst showed good cycling stability and the removal efficiency reached 85.77% after five cycles. Therefore, the as-prepared catalyst is an effective and sustainable material that can be used to remove HCHO from actual indoor polluted air. This paper provides ideas for the research and development of efficient catalysts.

The Co3O4/CN-x

As one of the significant pollutants in indoor air, formaldehyde (HCHO) has attracted increasing attention due to its negative effects on human health. Thus, to reduce formaldehyde pollution, herein, an Ag-promoted Cr/MnO2 catalyst (Ag/Cr/MnO2) was obtained via a hydrothermal-calcination method, which was employed for the catalytic oxidation of low-concentration indoor HCHO (∼1 ppm) at room temperature. The Ag/Cr/MnO2 catalyst eliminated approximately 98.62% HCHO within 14 h and maintained a high removal efficiency continuously under the dynamic test conditions. Furthermore, the catalyst exhibited good recycling stability and outstanding activity in a humid environment. Different characterization techniques were utilized to determine the physicochemical properties that contribute to improving the catalytic performance. The Ag substance contained metallic Ag (Ag0) as the main component and some Ag2O, and the Ag0 particles provided ample active sites for the catalytic oxidation of HCHO. Besides, the incorporation of Ag increased the reducibility of the catalyst and the content of Mn4+, Cr6+ and oxygen vacancies. The abundant active sites, high reducibility, rich Mn4+, Cr6+, oxygen vacancies, and surface lattice oxygen species, and the powerful interaction between Cr/MnO2 and Ag were the reasons for the splendid catalytic capability for HCHO by the Ag/Cr/MnO2 catalyst. In conclusion, the Ag/Cr/MnO2 catalyst can be a promising catalyst to degrade HCHO with practical application significance.

Exposure to formaldehyde (HCHO) may have serious harm to human health because of its existence in indoor air. It is a simple and effective solution to remove formaldehyde from the environment by adsorption. Activated carbon is the primary adsorbent for the formaldehyde pollution control strategy. In this study, bamboo-based activated carbon (BAC) was prepared from bamboo charcoal (BC) by boric acid activation method and applied to remove formaldehyde in the air at room temperature. The structure and physicochemical properties of BAC were investigated by N-2 adsorption-desorption, X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscope, thermogravimetric and X-ray photoelectron spectroscopy. The results showed that the oxygen-containing functional group, amorphous degree and specific surface area of BAC were improved compared with BC, which improved its formaldehyde removal performance. The specific surface area and formaldehyde removal rate of BAC were 289.21 m(2)/g and 93.25% respectively, which were 288.37 m(2)/g and 49.95% higher than those of BC. This study provides a new idea for a better understanding of BC adsorbent that controls HCHO pollutant.

The polycarboxylate superplasticizer (PCE) has been widely used in concrete products, tunnels, bridges and water conservancy projects due to its excellent characteristics. With the rapid development of the construction industry and the depletion of high-quality raw materials for concrete, sand and gravel containing clay have been used in concrete, which reduces the properties of PCEs. Recent studies have found that many PCEs structures without PEG/PPG or polyamine side chains have been developed due to the influence of montmorillonite (MMT) in clay on the fluidity of concrete. However, the influence mechanism of clay minerals in concrete on PCEs and the improvement methods are not summarized, and this paper has systematically overviewed this aspect. Firstly, HPEG-PCEs and APEG-PCEs in the PCEs market have superior cost effectiveness for concrete, while specific efficient PCEs such as zwitterion PCEs are suitable for calcination of clay cement mixtures to reduce anthropogenic CO2 emissions. Secondly, the chemical adsorption of clay to PCEs in concrete leads to a sharp decline in concrete fluidity, in which montmorillonite has the greatest effect, followed by illite and kaolin. Finally, methods such as modifying clay, increasing or reducing the steric resistance of PCEs, introducing special functional groups and adding sacrificial agents are discussed to improve the fluidity of concrete containing clay by changing the structure of clay layers and PCEs, thus saving the construction cost caused by the amount of raw materials and PCEs. In addition, the efficient application and future research of clay minerals and PCEs are also prospected.

The Co 3 O 4 /CN- x %CeO 2 ( x = 0, 3, 6) composites for enhanced photocatalytic degradation of formaldehyde (HCHO) performance were prepared by hydrothermal-calcination method. The structure, microstructure and surface functional groups of samples were investigated by using the X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and Fourier transform infrared spectrometer, and the degradation mechanism of Co 3 O 4 /CN-3%CeO 2 was also discussed this paper. The results showed that the Co 3 O 4 /CN-3%CeO 2 sample could degrade 91.5% of HCHO within 9 h which was 190% higher than that of the CN, and maintained excellent performance for 24 h. The sample was in the form of irregular block-based flakes and particles, the specific surface area was 111.92 m 2 /g which was 2.5 times than that of the CN sample. The sample was composed of CN and Co 3 O 4 phases, existed O–H, N–H, C=O, C–N, Co–O, Ce–O functional group and mesoporous structure with pore size distribution of 2 to 20 nm.

以季铵盐氯化胆碱(ChCl)与乳酸(Lac)、尿素(U)、草酸(OA)、甲酸(FA)分别合成低共熔溶剂(DES)并对工业碱木质素(AL)进行改性,研究了由不同氢键供体与ChCl合成的DES体系、反应条件及催化剂对碱木质素改性的木质素提取率的影响.研究发现使用氯化胆碱/乳酸低共熔溶剂(ChCl/Lac)时,木质素的提取率最高.通过单因素试验得到ChCl/Lac改性的最优条件为:在120℃时,Lac与ChCl物质的量比值(nLac/nChCl)为12,DES添加量为碱木质素质量的20倍(mDES/mAL=20),反应时间12 h,木质素提取率达95.37％;当反应温度降低到100℃,无催化剂时,木质素提取率为40.39％,使用8％碳酸钠为催化剂时,木质素提取率提高至74.87％.采用FT-IR、13 C NMR、TG和DTG对木质素样品进行表征,由FT-IR、13 C NMR结果可得,改性中β-O-4键断裂并引入羟甲基和甲氧基,改性后木质素主要结构单元为紫丁香基结构.从TG和DTG分析得到碳酸钠催化改性后木质素放热峰向高温移动,热稳定性提高.

The highly promising formaldehyde (HCHO)-removing materials are essential for eliminating interior pollution to safeguard the public's health with increasing indoor HCHO contamination situations being recorded on a global scale. In the paper, bamboo charcoal (BC) was activated with boric acid to prepare bamboo-based activated carbon (BAC), and then impregnated with ammonium acetate solution to successfully develop porous adsorbent with ammonium acetate particles (N/BAC), which was applied to remove low concentration of HCHO at room temperature. The adsorption performance for HCHO was systematically investigated while the surface chemical properties and microstructure of the as-prepared adsorbents were described and analyzed. The specific surface area, total pore volume and microporous volume of N/BAC sample were 240.09 m2/g, 0.27 cm3/g and 0.12 cm3/g, which increased by 42.40 m2/g, 0.15 cm3/g and 0.03 cm3/g compared with BAC sample, respectively. The specific surface area and the microporous volume, as well as the content of oxygen- and nitrogen-containing functional groups of N/BAC sample were augmented by contrast with other samples, and numerous ammonium acetate particles were present on the surface. Precisely because of this, the N/BAC sample exhibited a high removal rate of 98.89%, which was 18.38% greater than that of BAC sample. A superior correlation coefficient (0.9999) from the experimental values of the kinetics and the fitted values of the pseudo-second-order kinetic model demonstrated that the adsorption process of HCHO on N/BAC sample was physical-chemical combined adsorption. The adsorption of HCHO on N/BAC sample was investigated under different humidity, and the results showed that the adsorbent yet had excellent adsorption capacity (87.93%) under RH 75%. Moreover, the N/BAC sample was renewable, and the removal rate still reached 82.81% after five cycles of regeneration. Therefore, the as-prepared adsorbent is an effective, economical and sustainable material, and could be used to remove HCHO from real contaminated indoor air.

The purpose of this work is to investigate the effects of copper (II) sulfate on the formaldehyde release and the mechanical properties of urea formaldehyde (UF) adhesive. Copper (II) sulfate has been used as a formaldehyde scavenger in UF resin, and its effects on the physical and chemical properties of UF adhesive have been studied. Moreover, the mechanical properties and formaldehyde release of plywood prepared with modified UF resin have been determined. The UF resin has been characterized by Fourier-transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). FTIR spectra showed that the addition of copper (II) sulfate to the UF resin does not affect the IR absorptions of its functional groups, implying that the structure of UF is not modified. Further results showed that the free formaldehyde content of the UF resin incorporating 3% copper (II) sulfate was 0.13 wt.%, around 71% lower than that of the untreated control UF adhesive. With a copper (II) sulfate content of 3%, the formaldehyde release from treated plywood was 0.74 mg·L−1, around 50% lower than that from the control UF adhesive, and the bonding strength reached 1.73 MPa, around 43% higher than that of the control.

In this paper, Cr/MnO2 catalysts were prepared by hydrothermal–calcination method and applied to the catalytic oxidation of formaldehyde (HCHO) at room temperature. The effects of calcination temperature on the physicochemical properties of Cr/MnO2 catalysts were investigated by means of N2 adsorption–desorption, X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscope, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. Based on this, the formaldehyde removal mechanism of Cr/MnO2 catalysts was proposed. The results showed that the specific surface area, OII/OI, Mn4+/Mn3+ and Cr6+/Cr3+ ratios of the Cr/MnO2 catalysts varied with the calcination temperature. The Cr/MnO2 catalyst calcined at 400 °C (CM400) has higher specific surface area (64.6 m2/g) and oxygen vacancy content, so it exhibits better formaldehyde removal performance, which could reach 92.1% within 22 h. It is concluded that the high specific surface area, abundant oxygen vacancy content, rich Mn4+ and Cr6+ species are primary reasons for the excellent formaldehyde removal performance of CM400 sample. The Cr/MnO2 catalysts reveal great application potential in indoor formaldehyde degradation, and will be promising industrial formaldehyde degradation catalyst.

In this study, the feasibility and mechanism of Pb2+ and malachite green (MG) adsorption from wastewater using KMnO4-modified bamboo biochar (KBC) was evaluated. The KBC was characterized by SEM–EDS, XRD, FTIR and XPS. The adsorption results for Pb2+ conformed to pseudo-second-order kinetics and the Langmuir model theory. Unlike the case for Pb2+, the Freundlich model better described the adsorption behaviour of MG, indicating that adsorption occurred within multiple molecular layers. Both pseudo-first-order kinetics and pseudo-second-order kinetics fit the MG adsorption data well, indicating that physical adsorption was involved in the adsorption process. In addition, the maximum adsorption capacity for Pb2+/MG was 123.47/1111.11 mg·g−1, KBC had high adsorption capacities for Pb2+ and MG, and the mechanisms of Pb2+ adsorption were mineral precipitation, functional group complexation, and cation-π interactions, while the main mechanisms for MG adsorption were pore filling, π–π interactions, and functional group complexation. In this study, KMnO4-modified biochar was prepared and used as an efficient adsorbent, and showed good application prospects for treatment of wastewater containing MG and Pb2+.

The effects of the hydrothermal co-precipitation factors of hydrothermal temperature, hydrothermal time, calcination temperature and calcination time on the crystal structure, microstructure, lattice defect and formaldehyde removal properties at indoor temperature of MnO x -NiO composite oxide catalysts were investigated by using the X-ray diffactiono (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and the catalytic activity testing apparatus. The results showed that the formaldehyde removal rate of the catalysts would increase first and then decrease with increasing in the hydrothermal temperature, or hydrothermal time, calcination temperature, calcination time. The maximum formaldehyde removal rate at indoor temperature is 95.57% with the best technology of the catalysts is as the following: 0.0125 mol potassium permanganate, 0.005 mol nickel nitrate, 5 ml sodium oxalate solution, 0.5 ml ammonia solution, hydrothermal 5 h at 130 °C and then calcination 5 h at 200 °C, the loose spherical accumulation specimen was composed of amorphous and crystal, and existed abundant Mn 4+ species and lattice oxygen on the catalyst surface.

A Au-Ga alloy layer is synthesized on a Au sheet substrate at low temperature and a new nanoporous Au material is then prepared based on Ga removal from the Au-Ga alloy by a electrochemical method. X-ray diffraction analysis confirms that the grains of the newly formed Au layer are refined and scanning electron microscopy suggests that the newly formed Au layer has a nanoporous structure with a pore size of∼16 nm. The cyclic voltammetry curve of the prepared nanoporous Au in a 1 M KCl solution presents a square structure of a supercapacitor with a specific capacitance of mF·cm-2, which is 86 times that of the smooth Au electrode. The 4-mercaptobenzoic acid (4-MBA) modified nanoporous Au material is used as a Raman substrate to detect Hg2+ with surface-enhanced Raman scattering. from 1.0×10−10 mol·L-1 to 1.0×10−5 mol·L-1), and the limit of detection is 1.0×10−10 mol·L-1.

This study focused on measuring the pollution characteristics, the monthly and seasonal variation rule of formaldehyde in the teaching machine room of Guangxi Normal University from March 2016 to February 2018, and the correlation between formaldehyde concentration and temperature or humidity were also analyzed. The results indicated that seasonal and monthly variation rule of formaldehyde changed with temperature and humidity in the teaching machine room. The concentration of formaldehyde was higher in summer and autumn, while was lower in winter and spring. Further analysis indicated that there was a strongly positive correlation (R2>0.87, R2>0.85, R2>0.81, p<0.01) between formaldehyde concentration and temperature, relative humidity or absolute humidity. It concluded that the formaldehyde concentration increased with the increase in the temperature and humidity. The maximum concentrations of formaldehyde in sitting breathing area and standing breathing area were 0.442mg/m3, 0.445mg/m3 and 0.184mg/m3, 0.213mg/m3 in July 2016, 2017, respectively. After eleven years, the formaldehyde in the teaching machine room was still seriously exceeded the standard (0.1mol/L), and decreased the temperature or humidity could effective alleviate the level of indoor formaldehyde concentration.

The metal-modified Co3O4 sample (metal: Zn or Cr, Zn and Cr) was prepared through hydrothermal approach, and applied in low concentration of HCHO removal under room temperature. The Cr/Zn/Co3O4 exhibited the best formaldehyde removal activity and stability. The effect of dopants on the physicochemical properties of the Co3O4 samples was characterized by X-ray diffraction, Raman, N2 adsorption–desorption, scanning electron microscopy, transmission electron microscopy, thermogravimetric (TG-DTG) and X-ray photoelectron spectroscopy, resulting that the Cr/Zn/Co3O4 sample possessed the optimal specific surface area (177.53 m2/g, 3.4 times that of pure Co3O4). Meanwhile, Cr and Zn incorporated into Co3O4 lattice simultaneously and promoted the formation of defects, which is the prerequisite for increasing the reactive oxygen species of Cr/Zn/Co3O4. In addition, Cr6+/Cr3+ ion pairs in the sample could be an important role in the removal of formaldehyde. It is concluded that the ideal HCHO removal performance and stability of Cr/Zn/Co3O4 were associated with its high vacancy oxygen content, excellent specific surface area and the promotion of Cr6+/Cr3+ ion pairs.

采用甲醛去除性能动态测试装置研究Mn/Fe物质的量比、水热温度、水热时间、焙烧温度、焙烧时间等工艺因素对锰铁氧化物催化剂室温甲醛去除性能的影响.采用X-射线衍射仪、扫描电子显微镜、能谱分析仪、透射电子显微镜、傅里叶变换红外光谱仪分析锰铁氧化物催化剂结构、形貌、微区成分、表面官能团等.结果表明,影响锰铁氧化物催化剂室温甲醛去除率强弱的顺序为:焙烧温度>煅烧时间>Mn/Fe物质的量比>水热时间>水热温度;催化剂的最佳制备工艺为:Mn/Fe物质的量比1.8:1,水热温度140℃,水热时间8.0 h,焙烧温度150℃时,焙烧时间4.5 h,该条件下制备催化剂的室温甲醛去除率为96.14％,经6次循环使用后活性仅下降5.06％;锰铁氧化物样品由MnO2、Fe2 O3和非晶相组成,样品呈球形,平均粒径6.73 nm,表面官能团主要有O H伸缩吸收、NH弯曲振动、CH弯曲振动等.