The study was enforced to probe the conversion and migration behavior of phosphorus speciation in sludge and the biochar received from pyrolysis of municipal sludge (MS), town sludge (TS), and slaughterhouse sludge (SS). This study creatively used fractionation of soil phosphorus to further differentiate speciation of phosphorus in three sludges (MS, TS, and SS). According to the x-ray diffraction (XRD) analysis and sequential extraction, the study proved the dependence of P speciation conversion on pyrolysis temperature and different types of raw sludge. The results of P-fractionation indicated that Ca-bound IP (Ca-IP) content in all biochars significantly increased at pyrolysis temperature of 350–800 °C, and the proportion of soluble and loosely bound IP (SL-IP), aluminum-bound IP (Al-IP), and Fe-bound IP (Fe-IP) of MS and SS decreased. The difference is that the Al-IP in the TS increased slightly as the pyrolysis temperature increased. Among the three kinds of sludge, the Olsen-P of TS is the lowest because the content of Olsen-P in sludge will decrease with the decrease of pH in the process of sewage treatment after acidification. In addition, XRD patterns of three sludges and biochar further confirmed the low crystallinity of AlPO₄ minerals. Through in-depth research on the environmental behavior of phosphorus, this study might additionally provide essential knowledge for the recovery and utilization of phosphorus in sludge.

We synthesized and characterized amidoxime-modified Fe₃O₄/SiO₂ core-shell magnetic microspheres tailored for maximal U(VI) sorption efficiency from seawater. Through meticulous structure and spectroscopy analyses, the microspheres, which were designed with amidoxime functionality, exhibited remarkable U(VI) sorption capabilities compared to raw silica-coated Fe₃O₄ counterparts. The maximum percent uranium adsorption (98.57%) was achieved at 60 minutes with 0.05 g of adsorbent, using a synthetic solution of 25 mg L⁻¹ UO₂(CH₃COO)₂. 2H₂O at pH 7 and 25 ºC (298 K). The kinetic studies highlighted rapid equilibrium achieved within 1 hours. Following the pseudo-second-order model, the microspheres reflected a maximum sorption capacity of 24.286 mg g^-1 at pH 7 and 298 K. The U(VI)-loaded microspheres could be efficiently separated via an external magnetic field with adsorption efficiency of 91.67% at pH 6.5 and efficiently regenerated by HCl, indicating their potential for U(VI) preconcentration and separation from seawater. This research contributed to the development of high-performance sorbents for U(VI) removal and holds promise for solving the radioactive element elimination and enrichment, performing its stability, selectivity, and reusability across multiple cycles.

This study primarily focused on optimizing the performance of nipa (Nypafruticans)frond as an adsorbent for methylene blue (MB) dye, using the response surface methodology (RSM). The process of preparing nipafrond includes several key steps, such as washing, drying, and size reduction to 100 mesh. Subsequently, the adsorbent is activated using a 5%v/v HCl activator for 24 hours, and it is characterized by its functional groups using Fourier transform infrared spectroscopy (FT-IR). The composition of both the natural and activated nipa frond is examined through X-ray fluorescence (XRF), while the surface area of the samples is characterized using Brunauer-Emmett-Teller surface srea (BET) analysis. The adsorption characteristics are then tested as a function of two independent factors, including adsorbent mass (2.0, 3.0, and 4.0 g) and contact time (80–100 minutes), with an initial concentration of 50 mg/l MB. The statistical analysis, specifically analysis of variance (ANOVA), shows the substantial influence of these variables on the adsorption process. By applying the RSM model, the optimal conditions for MB adsorption are determined. These optimal conditions include nipa frond powder mass of 3.7071 g and a contact time of 83.1142 minutes, resulting in an optimum adsorption capacity of 2499 mg/g. The corresponding optimum adsorption efficiency is 99.7224%, with a desirability value of 0.974.

Worldwide population growth and consumerism have elevated the water pollution problem to the top of the environmental priority list, with severe consequences for public health, particularly in agricultural countries such as India, where water scarcity is a big challenge. Hence, greywater has the potential to be one of the most sustainable options to meet the growing need for freshwater with satisfying treatment options. This study focused on the assessment of electrocoagulation coupled with the filtration and adsorption processes in continuous modes and different electrode arrangements including (Al-Fe-Al-Fe), (Fe-Al-Fe-Al), (Al-Al-Al-Al) and (Fe-Fe-Fe-Fe) to investigate the effect of specific flow rates (i.e., 0.05 and 0.1 liters per minute) on the removal efficiency. The findings show that a 0.05 lit/min flow rate produces a higher removal efficiency approximately between 85 to 90% with an energy consumption of between 0.5 to 4.75 KWh/m³as compared to the 75 to 85% removal efficiency and 0.4 to 4 KWh/m³energy consumption at a flow rate of 0.1 lit/min. The operational cost is variable and mainly depends upon the energy consumption; moreover, it was found that the optimal results and economy variation shown by the electrode assembly of Al-Fe-Al-Fe was between 20 to 22 Indian rupees at a 24 volt current density and in each combination of electrodes.

Initial research was focused on the production of calcium-based alginate-chitosan membranes from coral skeletons collected from the Gulf of Prigi. The coral skeleton's composition was analyzed using XRF, revealing a calcium oxide content ranging from 90.86% to 93.41%. These membranes showed the significant potential for salt adsorption, as evidenced by FTIR analysis, which showed the presence of functional groups such as -OH, C=O, C-O, and N-H involved in the NaCl binding process. SEM analysis showed the particle size diameter of 185.96 nm, indicating a relatively rough and porous morphology. Under optimized conditions, the resulting calcium-based alginate-chitosan membrane achieved 40.5% Na⁺ and 48.39% Cl^- adsorptions, using 13.3 mL of 2% (w/v) chitosan and 26.6 mL of 2% (w/v) alginate with a 40-minutes contact time. The subsequent we applied for the desalination potential of calcium alginate, revealing the efficient reduction of NaCl levels in seawater. The calcium of coral skeletons collected was 90.86% and 93.41% before and after calcination, respectively, affirming the dominant calcium composition suitable for calcium alginate production. We identified an optimal 8-minute contact time for calcium alginate to effectively absorb NaCl, resulting in an 88.17% and 50% for Na⁺ and Cl^- absorptions. We applied the addition of chitosan into calcium-alginate membranes and its impact on enhancing salt adsorption efficiency for seawater desalination.

Novel catalysts for recycling PET bottles into monomers have been developed by depositing zinc onto the surface of SBA-15, mitigating ZnO catalyst agglomeration in glycolysis separation processes to enhance reaction yields. Various zinc compounds (Zn(OAc)₂, ZnCl₂, and ZnSO₄) were employed as substrates for catalyst design on the porous, high-surface-area material SBA-15 via impregnation. The presence of distinct Zn species on SBA-15 was confirmed through XRD and EDS analyses. The acidity of the catalyst, a crucial factor in the PET glycolysis process, was assessed using different Zn-containing precursors. NH₃-TPD measurement has revealed the highest acidity in ZnCl₂, followed by Zn(OAc)₂and ZnSO₄, respectively. Glycolysis reactions with a PET:EG ratio of 1:5 and a 1% catalyst at 200°C for 2 hours revealed the catalytic efficacy of zinc-deposited compounds in the sequence ZnCl₂ > Zn(OAc)₂ > ZnSO₄. Surprisingly, the ZnCl₂ catalyst produced the highest yield of bis-2-hydroxyethyl terephthalate (BHET) at 75% and displayed exceptional recycling capability over three cycles, contributing significantly to resource recovery objectives aligned with the Sustainable Development Goals (SDGs).