Renewable adsorbents from the solid residue of sewage sludge hydrothermal liquefaction for wastewater treatment

Remarkable purification of organic dyes by NiOOH-modified industrial waste residues

Extracting functional materials from industrial waste residues to absorb organic dyes can maximize waste reuse and minimize water pollution. However, the extraordinarily low purification efficiency still limits the practical application of this strategy. Herein, the lamellar NiOOH is in-situ anchored on the industrial waste red mud surface (ARM/NiOOH) as an adsorbent to purify organic dyes in wastewater. ARM/NiOOH adsorbent with high specific surface area and porosity provides considerable active sites for the congo red (CR), thereby significantly enhancing the removal efficiency of CR. Besides, we fit a reasonable adsorption model for ARM/NiOOH adsorbent and investigate its adsorption kinetics. Resultantly, ARM/NiOOH adsorbent can remarkably adsorb 348.0 mg g-1 CR within 5 min, which is 7.91 times that of raw RM. Our work provides a strategy for reusing industrial waste and purifying sewage pollution, which advances wastewater treatment engineering.

Removal of Benzene and Toluene from Synthetic Wastewater by Adsorption onto Magnetic Zeolitic Imidazole Framework Nanocomposites

Considering the risk associated with exposure to benzene and toluene in water resources, researchers have been motivated to conduct studies to remove them from aqueous solutions. Thus, by performing the present study, the potential of Fe₃O₄/zeolite imidazolate framework nanoparticles (Fe₃O₄@ZIF-8) was evaluated for the adsorption of benzene and toluene. Accordingly, the solution pH, Fe₃O₄@ZIF-8 dosage, mixing time, concentration of benzene and toluene, and temperature, were the parameters considered for conducting the batch experiments, for which their effect on adsorption efficiency was evaluated. Our conducted experiments introduced the neutral pH as the best pH range to obtain the maximum removal. Fitting the adsorption data into the various models revealed the aptness of the Langmuir isotherm equation in describing experimental information and highest adsorption capacity; for benzene it was 129.4, 134.2, 137.3, and 148.2 mg g^-1, but for toluene it was 118.4, 125.2, 129.6, and 133.1 mg g^-1, for temperature 20, 30, 40, and 50 °C, respectively. Using obtained optimal conditions, the adsorption efficiencies of benzene and toluene were obtained to be 98.4% and 93.1%, respectively. Kinetic studies showed acceptable coefficients for PSO kinetics and confirmed its suitability. Also, the recyclability results showed that for six consecutive periods of the adsorption-desorption process, the percentage of removal decreased by only 6% for benzene and toluene. Moreover, calculating thermodynamic parameter changes for benzene and toluene removal confirmed the favorability and spontaneity of the studied process and its endothermic nature. Considering the above findings, Fe₃O₄@ZIF-8 was found to be an operative adsorbent for removing pollutants.