Phosphorus (P) recovery from sewage sludge (SS) have been regarded as an effective method of P recycling. The effects of incineration temperature, incineration time, and chlorine additives on the distribution of P speciation during sludge incineration were studied. Moreover, the reactions between model compounds AlPO₄ and additives (MgCl₂ and CaCl₂) were investigated by thermogravimetric differential thermal analysis and X-ray diffraction measurements. The results demonstrated that the increase in temperature and time stimulated the volatilization of non-apatite inorganic phosphorus (NAIP) instead of apatite phosphorus (AP). MgCl₂ and CaCl₂ can greatly promote the conversion of NAIP to AP. Additionally, AlPO₄ reacted with MgCl₂ are incinerated at 500–600 °C to form Mg₃(PO₄)₂, which is mainly due to the reaction of the intermediate product MgO and AlPO₄. Reactions between AlPO₄ and CaCl₂ occurred at 700–750 °C and produced Ca₂PO₄Cl, which can be directly used with high bioavailability. These findings suggested that chlorine additives in the SS incineration process can obtain phosphorus-containing minerals with higher bioavailability to realize the resource utilization of P in sludge.

Photosynthetic microalgal growth is a promising tool for mitigation of gaseous effluent from the cement production, which is highly implicated in global warming and climate change. We investigated the effects of actual cement industry flue gas on the physiology of Chlorella vulgaris under laboratory-controlled conditions. We evaluated the growth, photosynthetic performance, intracellular metal content, total proteins, and carbohydrates of C. vulgaris under three gas input rates: 9, 36, and 54 L d⁻¹; compressed air (54 L d⁻¹) was used as control. The results showed no correlation between the flue gas input rates on total proteins and carbohydrates in the algal biomass, and no effects on growth rates. However, rapid light curves indicated that the light use efficiency (α) and the maximum relative electron transport rate (rETRₘₐₓ) were stimulated when applying 9 and 36 L d⁻¹. Metal analysis revealed an accumulation of Cr, Zn, and Ni in the algal biomass exposed to flue gas (54 L d⁻¹) compared to the control. Thermogravimetry and differential thermal analysis showed that 70% of the cement kiln dust were composed by uncalcined limestone, which may have stimulated photosynthesis, as indicated by the rapid light curve parameters. In general, C. vulgaris can be considered a robust organism for cement flue gas bioremediation.

The efficiency of the as-prepared Mg₀.₂₅Co₀.₇₅Fe₂O₄ spinel nanoparticles for adsorption of crude oil from aqueous solution was improved by blending them with chitosan hydrogel (CH) prepared using epichlorohydrin as cross-linker resulting (CH/Mg₀.₂₅Co₀.₇₅Fe₂O₄) nanocomposites. Mg₀.₂₅Co₀.₇₅Fe₂O₄ nanocrystals was prepared by the chemical co-precipitation method and characterized by using X-ray diffraction (XRD), infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM), and differential thermal analysis (DTA)/thermogravimetric analysis (TGA). DTA/TGA results showed that the net weight loss of the samples heated from room temperature up to 1000 °C lies in the range 2.2–26.5% weight, where the maximum weight loss appeared at 100 °C and 614 °C. The blending nanocomposites prepared, were characterized by FT-IR and SEM micrographs. The effect of the nanoparticles ratio on the water uptake of nanocomposites and their capability to adsorb the crude oil was estimated by the gravimetric method. TEM results showed that the average nanoparticle size (Z) of Mg₀.₂₅Co₀.₇₅Fe₂O₄ is 30.06 nm and the SEM illustrated the presence of a very clear and rough layer of pores which are homogenously arranged structures that could play an important role in the adsorption and stability of crude oil on polymers. The adsorption ability of crude oil from waste water on the CH/Mg₀.₂₅Co₀.₇₅Fe₂O₄ nanocomposites hydrogel was reported and it was found that the CH/Mg₀.₂₅Co₀.₇₅Fe₂O₄ with 95/5% ratio showed the improvement in the oil adsorption (72.5%) than the 0/100% one (50.2%). As a consequence, it is highly suggested that the potential of blending CH with Mg₀.₂₅Co₀.₇₅Fe₂O₄ to obtain CH/Mg₀.₂₅Co₀.75Fe2O₄ for enhancing crude oil adsorption in oily waste water treatment with a low cost.

As a commonly used surfactant, sodium dodecyl sulfate (SDS) usually coexists with inorganic anions in the industrial wastewater. These anions have a significant influence on SDS removal, indirectly threatening the environment. It is important to understand the relationship between the adsorption of SDS and inorganic anions. In this study, calcium-based layered double hydroxide (CaAl-LDH-Cl) as an efficient adsorbent was synthesized for investigating the effect of SO₄²⁻ on SDS removal. The SDS adsorption capacities were enhanced to 3.21 and 4.21 mmol g⁻¹ in the presence of SO₄²⁻ with low/high SDS concentration, respectively. The phenomenon and mechanism were confirmed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and Scanning electron microscopy (SEM). Anionic exchange played a dominant role in the adsorption of SDS onto CaAl-LDH-Cl at DS⁻/SO₄²⁻ < 2, while both anion exchange and precipitation occurred when DS⁻/SO₄²⁻ exceeded 2. Moreover, the thermal analysis (TG–DTA) was employed to further reveal the interaction mechanism. The results showed the highest total mass loss and the lowest loss temperature of interlayer water in the sulfate coexist system, confirming the enhancement of SDS adsorption amount in the presence of SO₄²⁻.

ZnAl-layered double hydroxide-loaded banana straw biochar (ZnAl-LDH-BSB) was prepared via the hydrothermal method, and the efficient phosphorus removal agent ZnAl-LDO-BSB was obtained by calcination at 500 °C. Based on the ZnAl-LDO-BSB adsorption characteristics, the adsorption mechanism was evaluated via TG/DTA, FTIR, XRD, SEM, HRTEM, and other characterization methods. The results showed that the ZnAl-LDO-BSB assembled into microspheres with typical hexagonal lamellar structures and presented good thermal stability. The adsorption of total phosphate (TP) by ZnAl-LDO-BSB conforms to the Langmuir model, and the theoretical maximum adsorption capacity is 185.19 mg g⁻¹. The adsorption kinetics were in accordance with the second-order kinetic model, and the anion influence on TP adsorption followed the order CO₃²⁻ > SO₄²⁻ > NO₃⁻. The combination of zeta potential measurements with the FTIR, XRD, SEM, HRTEM, and XPS results suggested that ZnAl-LDO-BSB adsorbs TP mainly by electrostatic adsorption, surface coordination, and anion intercalation. Graphical abstract

High concentrations of antibiotic compounds within pharmaceutical wastewater have hazardous impacts toward environment and human health. Therefore, there is an immediate requirement of efficient treatment method for removal of antibiotics from aquatic environment. In the present study, the cryptomelane catalyst-type manganese oxide octahedral molecular sieve (K-OMS-2) was synthesized in the presence of benzyl alcohol as a reducing agent and cetyltrimethylammonium bromide as a structure-directing agent and then utilized to reduce the metronidazole. The central composite design method was the experimental design adopted. The FESEM analysis revealed that the K-OMS-2 surface contained many uniformly cylindrical aggregates less than about 40 nm in diameter and about 80–100 nm in length. Besides, a high specific surface area of 129 m²/g and average pore size of 45.47 nm were recorded. According to the TGA/DTA analysis, the prepared catalyst revealed high thermal stability. The maximum metronidazole degradation (95.36%) was evident at conditions of pH = 3, catalyst mass = 0.97 g/L, contact time = 200 min, and metronidazole concentration = 20 mg/L. Metronidazole did not form a complex with nitrate, fluoride, sulfate, or hardness. These ions exerted a negligible effect on metronidazole reduction using the K-OMS-2 catalyst, except for hardness, which reduced the removal efficiency of metronidazole by 17%. The FTIR and LC-MS revealed a complex mechanism involved in the metronidazole degradation by the K-OMS-2 involving the formation of an amino group, a hydroxyelated compound via N-denitration, and hydrogenation process on the K-OMS-2 catalyst surface.

In this paper, we have analyzed parts of printed circuit board (PCB) and liquid crystal display (LCD) screens of mobile phones and computers, quantitative and qualitative chemical compositions of individual components, and complete PCBs were determined. Differential thermal analysis (DTA) and differential scanning calorimetry (DSC) methods were used to determine the temperatures of phase transformations, whereas qualitative and quantitative compositions of the samples were determined by X-ray fluorescence spectrometry (XRF), inductively coupled plasma optical emission spectrometry (ICP-OES), and scanning electron microscopy (SEM)-energy dispersive X-ray spectrometry (EDS) analyses. The microstructure of samples was studied by optical microscopy. Based on results of the analysis, a procedure for recycling PCBs is proposed. The emphasis was on the effects that can be achieved in the recycling process by extraction of some parts before the melting process. In addition, newly developed materials can be an adequate substitute for some of the dangerous and harmful materials, such as lead and arsenic are proposed, which is in accordance with the European Union (EU) Restriction of the use of certain hazardous substances (RoHS) directive as well as some alternative materials for use in the electronics industry instead of gold and gold alloys.

Fluoride can cause some diseases to humans when ingested in large quantities and for a long time. Due to this, it is necessary to remove or reduce the amount of fluoride in effluents before release into the water bodies. This work aimed to evaluate the ability of hydrocalumites synthesized by two different methodologies and calcined hydrocalumite in reducing the content of fluoride in aqueous solutions. The materials were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), N₂ physisorption, thermogravimetric analysis (TGA), and differential thermal analysis (DTA). The removal capacity of fluoride ions ranged from 14.9 to 189.6 mg F⁻ g⁻¹. The removal mechanisms by hydrocalumites were ion exchange and adsorption at low concentrations, while at high concentrations were adsorption and precipitation of calcium fluoride. In relation to the use of calcined hydrocalumite, the removal mechanisms were ion exchange and reconstruction of structure (memory effect) in low concentrations. By the adsorption tests, it was observed that the results fit better the Langmuir isotherm model.

Preparation of Ce₂(MoO₄)₃ nanoparticles is reported via the microemulsion method by using two different surfactants, i.e., cationic surfactant, cetyltrimethylammonium bromide (CTAB), and nonionic surfactant, Triton X-100. The water pools produced in the microemulsion systems behave as nanoreactors for reaction of the cerium (3+) and molybdate ions to produce Ce₂(MoO₄)₃ nanoparticles. The structure and morphology of the products were characterized by using Fourier-transform infrared (FT-IR) spectroscopy, energy-dispersive X-ray analysis (EDX), UV-Vis spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA-DTA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The prepared Ce₂(MoO₄)₃ nanoparticles were successfully utilized as photocatalysts to remove crystal violet from aqueous solution in which the maximum percentage of dye degradation was about 89% after 5 h under the visible light irradiation. Also, kinetic study of the photocatalytic degradation revealed that pseudo-second order model is the best one for describing kinetic of the reaction.

In this study, we investigated the effects of SiO₂ nanoparticles (SiO₂-NPs) (1, 10, 25, 50, and 100 mg/L) for 24 h in vitro on the motility parameters and oxidative stress markers such as total glutathione (TGSH), catalase (CAT), and malondialdehyde (MDA) of rainbow trout, Oncorhynchus mykiss sperm cells. Therefore, SiO₂-NPs were synthesized with sol-gel reaction from tetraethoxy orthosilicate (TEOS). The prepared nanoparticle structures were characterized for chemical structure, morphology and thermal behavior employing Fourier transform infrared spectroscopy, X-ray spectroscopy, scanning electron micrograph, and thermal analysis (DTA/TGA/DSC) techniques. After exposure, there was statistically significant (p < 0.05) decreases in velocities of sperm cells. CAT activity significantly (p < 0.05) decreased by 9.6% in sperm cell treated with 100 mg/L. In addition, MDA level significantly increased by 70.4% and 77.5% in sperm cell treated with 50 and 100 mg/L SiO₂-NPs, respectively (p < 0.05). These results showed that SiO₂-NPs may have toxic effect on rainbow trout sperm cells in 50 mg/L and more.