In this study, a dual-ligand collector, N1, N2-oxalyl-N3, N4-di-n-butyldithiourea (BDBAO), was designed and synthesized, which contains two thiourea groups in its structure. It was used as a chalcopyrite collector for flotation separation of chalcopyrite and pyrite. The impact of BDBAO on the flotation behavior of chalcopyrite and pyrite was systematically investigated by micro-flotation experiments, and the adsorption mechanism of BDBAO at chalcopyrite interface was studied in details by contact angle measurements, FT-IR, XPS, SEM-EDS and DFTB+ simulation. Compared to the traditional collector O-isopropyl-N-ethyl thionocarbamate (Z-200), BDBAO exhibited the stronger collecting ability and excellent selectivity for chalcopyrite. BDBAO was capable of effectively separating chalcopyrite and pyrite at pH 9.0 similar to 11.0. The adsorption mechanism study indicated that BDBAO undergoes chemical adsorption onto the chalcopyrite surface, primarily via the interaction between two C = S groups in the BDBAO structure and Cu+ ions present on the chalcopyrite surface, resulting in the formation of a C-S-Cu bonds. This interaction resulted in the formation of a stable double-chelate ring structure on chalcopyrite surface, thereby enhancing the adsorption capacity of BDBAO, which was well confirmed by FT-IR, XPS spectrum analysis results and DFTB+ simulations.

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.

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.

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.

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.