This work presents studies on the co-combustion of anthracite coal and wood pellets in fluidized bed. Prior to the fluidized bed combustion, thermogravimetric analysis are performed to investigate the thermodynamic behavior of coal and wood pellets. The results show that the thermal decomposition of blends is divided into four stages. The co-firing of coal and wood pellets can promote the combustion reaction and reduce the emission of gaseous pollutants, such as SO₂ and NO. It is important to choose the proportion of wood pellets during co-combustion due to the low combustion efficiency caused by large pellets with poor fluidization. Wood pellets can inhibit the volatilization of trace elements, especially for Cr, Ni and V. In addition, the slagging ratio of wood pellets ash is reduced by co-firing with coal. The research on combustion of coal and wood pellets is of great significance in engineering.

Antibiotics residuals in the environments receive wide concerns due to the high risk of generating antibiotic resistance. Natural organic matters (NOM) existed in the environments are considered to have the capacity of binding with organic contaminants, consequently influencing their speciation and transformation in the natural environments. To assess the migration of antibiotics in the environments, it is crucial to understand the binding mechanisms between NOM and antibiotics, which is still unclear due to the limit of available research methods. In this study, the interaction between fulvic acids (FA), one of the main components of NOM, and sulfamethazine (SMZ) was characterized by nuclear magnetic resonance (NMR) combined with surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC) technology. The parameters related to kinetics and thermodynamics of the interaction were determined, and the possible mechanisms driving the interaction were also proposed. In addition, density functional theory (DFT) was used to predict the binding mode between FA and SMZ to reveal the interaction mechanism. Results indicate that FA can effectively bound with SMZ to form a stable complex with a binding constant at the level of 10³ L/mol. The kinetic parameters including association and dissociation constants were 29.4 L/mol/s and 6.64 × 10⁻³ 1/s, respectively. Hydrophobic interaction might play significant roles in the binding interaction with ancillary contribution of π-π conjunction arising from the aromatic rings stacking of FA and SMZ.

The hierarchical core-shell and yolk-shell magnetic titanate nanosheets (Fe3O4@TNS) were successfully synthesized by employing magnetic nanoparticles (NPs) as interior core and intercrossed titanate nanostructures (NSs) as exterior shell. The as-prepared magnetic Fe3O4@TNS nanosheets had high specific areas (114.9 m2 g−1 for core-shell Fe3O4@TNS and 130.1 m2 g−1 for yolk-shell Fe3O4@TNS). Taking advantage of the unique multilayer structure, the nanosheets were suitable for eliminating U(VI) from polluted water environment. The sorption was strongly affected by pH values and weakly influenced by ionic strength, suggesting that the sorption of U(VI) on Fe3O4@TNS was mainly dominated by ion exchange and outer-sphere surface complexion. The maximum sorption capacities (Qmax) calculated from the Langmuir model were 68.59, 121.36 and 264.55 mg g−1 for core-shell Fe3O4@TNS and 82.85, 173.01 and 283.29 mg g−1 for yolk-shell Fe3O4@TNS, at 298 K, 313 K and 328 K, respectively. Thermodynamic parameters (ΔH0, ΔS0 and ΔG0) demonstrated that the sorption process was endothermic and spontaneous. Based on X-ray photoelectron spectroscopy (XPS) analyses, the sorption mechanism was confirmed to be cation-exchange between interlayered Na+ and UO22+. The yolk-shell Fe3O4@TNS had more extraordinary sorption efficiency than core-shell Fe3O4@TNS since the yolk-shell structure provided internal void space inside the titanate shell to accommodate more exchangeable active sites. The flexible recollection and high efficient sorption capacity made core-shell and yolk-shell Fe3O4@TNS nanosheets promising materials to eliminate U(VI) or other actinides in wastewater cleanup applications.

Most drugs are synthesized by human medicine both for the treatment of men and animals and are also produced to maintain their physical and chemical properties for a time sufficient to serve a therapeutic purpose in treatments of some kind of illness. Ciprofloxacin is an antibiotic synthetically obtained in 1987 and belongs to the family of fluoroquinolones and is currently prescribed in certain treatments. This work was developed with the objective of evaluating the adsorption of the ciprofloxacin antibiotic in solution on zinc oxide (ZnO) supported on SBA-15-type mesoporous silica. The results showed that the post-synthesis method is effective in impregnating zinc oxide in SBA-15 and its structure has not been damaged and has not lost its organization in the hexagonal 2D planes. The ZnO-SBA-15 (10%) sample adsorbed 69.10% of ciprofloxacin (25 mg/L) in 180 min. Freundlich adsorption model was observed with the correlation factor of R² = 0.9999, for the adsorbent ZnO-SBA-15 (10%), which showed the best sample. The kinetics was classified as pseudo-second order, as well as the thermodynamic parameters were determined, showing that the process has a spontaneous nature and a value of ΔH° = 4.677 kJ/mol, evidencing that the process has the nature of physiosorption.

The nanoporous carbon using waste straw as carbon source was well prepared for effective dye removal from aqueous solution. The structure and surface properties of nanoporous carbon were characterized by X-ray diffraction, Raman spectroscopy, N₂ adsorption–desorption, and X-ray photoelectron spectroscopy. The results revealed that the nanoporous carbon exhibited large specific surface area and porous structure with abundant functional groups on the surface. In the adsorption experiments, the nanoporous carbon showed high dye adsorption capacity and rapid removal rate under higher pH value, initial dye concentration, and dosage of adsorbents. Moreover, the adsorption isotherm data fitted well to the Langmuir model, suggesting the monolayer adsorption. The maximum adsorption capacity could reach 555.56 mg/g, much higher than the recent reports. Besides, the adsorption kinetics fitted well to the pseudo-second-order model and the correlation coefficients were greater than 0.999. Thermodynamic study results indicated that dye adsorption onto the hierarchical nanoporous carbon was spontaneous and thermodynamically favorable. Therefore, with larger specific surface area and porous structure, the nanoporous carbon showed great potential as efficient adsorbents for dye in the aqueous environment.

Adsorption has been researched attempting to minimize the pollution caused by dyes, which represents a serious environmental problem as contamination of surface and ground water. Therefore, cellulose and its modified forms with amine and thiols groups constitute a class of versatile adsorbents for the removal of anionic dyes in aqueous solution. In this context, this work reports the preparation of cellulose modified by ethylene sulfide and ethylenediamine (Cel-ESEN), through the reaction of the cellulose modified by ethylene sulfide (CEL-ES) and ethylenediamine (EN). Materials were characterized by elemental analysis, which showed in the Cel-ESEN matrix 10.12 ± 0.10%, 5.52 ± 0.06% of sulfur and nitrogen, respectively. Nuclear magnetic resonance in the solid state of ¹³C (¹³C NMR) showed, for the Cel-ESEN matrix, a peak related to CH₂ groups from the molecules incorporated in the cellulose biopolymer. Crystalline Index obtained by X-ray diffraction (XRD) was in the order pure Cellulose > Cel-Cl > Cel-ES > Cel-ESEN. The adsorbent matrix (Cel-ESEN) was used in the removal of the remazol yellow GR (RY) dye in aqueous medium. Data obtained experimentally from kinetic study had the best adjustment to the proposed pseudo-second-order model. The adsorption process occurs in monolayer, is endothermic and thermodynamically favorable. Adsorption capacity of the modified material became 118 times higher than the starting material. These results suggest that the obtained biopolymer can be used as an alternative material to remove RY in aqueous solution.

In this paper, reduced graphenoxide/attapulgite (rGO/APT)-supported nanoscale zero-valent iron (nZVI) composites (rGO/APT-nZVI) were synthesized to remove acid red 18 (AR18) and other organic dyes from aqueous solutions. The structure of synthetic rGO/APT-nZVI composite was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD), and the removal properties of rGO/APT-nZVI on AR18 were investigated. The factors of various experimental parameters (ratio, pH, initial concentration, temperature, and time) impacting on removal of AR18 were studied as well. Comparison experiment of different materials showed that 93.5% of AR18 was removed using rGO/APT-nZVI, while only 7.9% and 64.8% of AR18 were removed using rGO/APT-nZVI after reacting for 30 min with an initial AR18 concentration of 100 mg L⁻¹, respectively. Moreover, kinetic and thermodynamic analyses were used to study the reduction process, and possible mechanism of AR18 removal was discussed. The results show that the rGO/APT-nZVI composites can effectively degrade AR18 over a wide range of pH and keep degradation activity in a long storage. In addition, the superior behaviors for other organic dyes removal highlight the great potential as an efficient adsorbent for water pollution.

A peanut shell-derived oxidized activated carbon (OAC) with high surface area was prepared by zinc chloride (ZnCl₂) chemical activation and subsequent nitric acid oxidation. OAC was characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), and N₂ adsorption-desorption. The results showed that OAC had the surface area of 1807 m² g⁻¹, with the total pore volume of 0.725 cm³ g⁻¹ and average pore diameter of 3.8 nm. More importantly, when OAC acted as an adsorbent, it exhibited high efficiency to remove basic blue 41 (BB-41), congo red (CR), phenol, Cr(VI), and Pb(II) from aqueous solution due to its universality in adsorption. Batch adsorption experiments were carried out to study the effect of various parameters such as pH, initial concentration, temperature, and contact time. Also, the isotherms, kinetic models, and thermodynamics of adsorption process were investigated. The equilibrium data for CR and Pb(II) were fitted to Langmuir isotherm model, while Freundlich model was suitable for the equilibrium isotherm of BB-41, phenol, and Cr(VI), respectively. As the result indicated, peanut shell was a suitable raw material to synthesize OAC which could be employed as an efficient and universal adsorbent for removing organic pollutants and heavy metal ions from wastewater.

Mn-Zn ferrite (Mn₁ ₋ ₓZnₓFe₂O₄, x = 0.2, 0.4, 0.6, and 0.8) nanomaterials were prepared by bioleaching and hydrothermal synthesis from waste Zn-Mn batteries. The materials were characterized by XRD, SEM, BET, VSM, CEC, and isoelectric point. It turned out when x = 0.4, synthesized Mn-Zn ferrite had best performance which was nanoferrite crystal structure with a specific surface area that reached 37.77 m²/g, the saturation magnetization was 62.85 emu/g, and isoelectric point and the CEC value were 7.33 and 43.51 mmol/100 g, respectively. In addition, the adsorption characteristics on Ni²⁺ were explored. The results of experiment suggested that data was more in line with the Freundlich model compared with Langmuir and Dubinin-Radushkevich isotherm models. Kinetics studies showed that pseudo-second-order kinetics was more suitable for describing the Ni²⁺ adsorption process where the maximum theoretical adsorption quantity was 52.99 mg/g. Thermodynamic parameters indicated the adsorption process can be spontaneous as an endothermic reaction, and warming was advantageous to adsorption. Besides, the adsorbent could be reused for six cycles with high removal efficiency. The magnetic and adsorptive properties of the adsorbent were promising, which had a high application value. Graphical abstract Fabrication process of nanometer ferrite by biological technology and hydrothermal synthesis for removal of Ni2+

The time-dependent uptake of metal ions (Al, Cr, Fe, Zn, Sr, and Ba) by cyanobacterium Arthrospira platensis from the complex industrial effluents of an engineering company (electroplating units of the Tactical Missiles Corporation, Dubna, Russia) was investigated. The preference of spirulina biomass for metal ions was observed as follows: Ba >Fe > Sr > Al > Zn > Cr. According to neutron activation analysis data, the degree of metal retention increased rapidly in the first 5–15 min of the reaction but remained the same or slightly decreased after this period. The efficiency of metal removal varied from 37% for chromium to 100% for barium. The thermodynamic analysis of wastewater chemical composition was performed in order to determine the speciation of heavy metals. Ion exchange, precipitation, and metal ion interaction with functional groups of the cyanobacteria cell wall were defined as the main mechanisms of metal ion removal.