A new nano-silica/chitosan (SiO₂/CS) sorbent was created using a wet process to eliminate uranium(VI) from its solution. Measurements using BET, XRD, EDX, SEM, and FTIR were utilized to analyze the production of SiO₂/CS. The adsorption progressions were carried out by pH, SiO₂/CS dose, temperature, sorbing time, and U(VI) concentration measurements. The optimal condition for U(VI) sorption (165 mg/g) was found to be pH 3.5, 60 mg SiO₂/CS, for 50 min of sorbing time, and 200 mg/L U(VI). Both the second-order sorption kinetics and Langmuir adsorption model were observed to be obeyed by the ability of SiO₂/CS to eradicate U(VI). Thermodynamically, the sorption strategy was a spontaneous reaction and exothermic. According to the findings, SiO₂/CS had the potential to serve as an effectual sorbent for U(VI) displacement.

The need to get uranium out of leaching liquid is pushing scientists to come up with new sorbents. This study uses the wet technique to improve the U(VI) sorption properties of ZrO₂/chitosan composite sorbent. To validate the synthesis of ZrO₂/CS composite with Zirconyl-OH, -NH, and -NH₂ for U(VI) binding, XRD, FTIR, SEM, EDX, and BET are used to describe the ZrO₂/chitosan wholly formed. To get El Sela leaching liquid, it used 150 g/L H₂SO₄, 1:4 S:L ratio, 200 rpm agitation speed, four hours of leaching period, and particle size 149–100 µm. In a batch study, the sorption parameters are evaluated at pH 3.5, 50 min of sorbing time, 50 mL of leaching liquid (200 mg/L U(VI)), and 25 °C. The sorption capability is 175 mg/g. Reusing ZrO₂/CS for seven cycles with a slight drop in performance is highly efficient, with U(VI) desorption using 0.8 M acid and 75 min of desorption time. The selective U(VI) recovery from El Sela leachate was made possible using ZrO₂/CS. Sodium diuranate was precipitated and yielded a yellow cake with a purity level of 94.88%.

A schematic diagram of the proposed Phragmites australis biochar and anion interactions.

The rising volume of sludge production poses significant environmental threats. Sludge has a high moisture content (MC), which increases its disposal and transport expenses. On the other hand, sludge has low dewaterability due to its high concentration of soluble organic compounds. To reduce sludge production, understanding and improving preconditioning and mechanical dewatering are crucial for breakthroughs in advanced sludge dewatering. The sludge samples used in this analysis were obtained from the Sarabium municipal wastewater treatment plant, with a moisture content of 97% and a specific filtration resistance (SRF) of 9.15463 × 10¹⁵ m/kg. Sludge dewatering was enhanced by treating the samples chemically with ferric chloride, aluminum sulfate, Moringa olifera, and cationic polyacrylamide CPAM and physically with wood chips, slag, rice husk, and wheat straw. The experiments examined the sludge’s initial characterization (specific resistance to filtration (SRF) and time to filtrate (TTF)). To verify the structural characteristics (density), elemental composition, and the presence of various functional groups, a characterization investigation was conducted using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and energy-dispersive X-ray spectroscopy (EDS). The results showed that chemical conditioning with ferric chloride is better than aluminum sulfate and Moringa. Wood chips also provide better results for physical conditioning than rice husk, wheat straw, and slag. The reaction occurred at the carbonyl group, where FTIR showed more activated sites during SEM analysis, as evidenced by the FTIR results. Still, when CPAM was added to conditioned sludge, there was no difference in sludge dewatering performance, and the activated sites remained unchanged. Hence, this research found that mechanical sludge dewatering was improved by conditioning with ferric chloride (pH of 6 and dose of 0.12 g/g of dry solid) and wood chips (dose of 1.5 g/g of dry solid), which reduced sludge volume after dewatering by 82.5% under low pressure, which in turn minimizes transportation, energy, and handling costs. This study supports SDG 3 and SDG 6 by improving sludge dewatering efficiency and promoting sustainable wastewater management using natural wood chips.