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In this research, the potential application of Pistacia soft shell (PSS) was investigated as a novel bio-based flocculant for pulp and paper wastewater (PPWW) treatment. In line with this, after characterization of the PSS, the removal efficiencies of chemical oxygen demand (COD), turbidity and heavy metals (Cu2+ and Pb2+) from PPWW were investigated with different dosage of PSS. The results were compared with alum as a reference flocculant. In addition, the effect of pH adjustment on the flocculation-adsorption performance of PSS was studied under acidic and alkaline condition. Zeta potential, BET, FTIR and SEM as well as kinetics and isotherm analyses were conducted for mechanistic understanding. According to the results, PSS treatment could remove COD, turbidity, Cu2+ and Pb2+ up to 67%, 87%, 70% and 74%, respectively which were better than alum: 56%, 85%, 31% and 35%. It was observed that, pH adjustment significantly improved the performance of PSS treatment. Maximum removal efficiencies of 92%, 95%, 97% and 98% were achieved for COD, turbidity, Cu2+ and Pb2+, respectively, under optimal condition of using 2 g/L PSS at pH 9. The mechanism analysis revealed that the high removal efficiency of PSS is related to the dual flocculation-adsorption of bridging and sweeping mechanisms. The results of this study suggested PSS as a promising, sustainable and eco-friendly bio-based flocculant and adsorbent for industrial wastewater treatment. [Display omitted] • Pistacia soft sell can be used as a natural flocculant for wastewater treatment. • A removal of 67% and 87% were achieved for COD and turbidity, respectively. • 74% and 70% removal efficiencies were achieved for Pb2+ and Cu2+, respectively. • PH adjustment showed a synergy effect on Pistacia soft sell performance. • Optimum conditions were determined as Pistacia soft sell dosage of 2 g/L and pH 9. [ABSTRACT FROM AUTHOR]

Inverse vulcanized polysulfides have been used as low-cost and effective adsorbents to remediate heavy metals in wastewater. Inverse vulcanization introduces sustainable polysulfide synthesis by solving the rapid desulfurization problem of unstable polysulfides, and provides superior performance compared to conventional commercial adsorbents. The review discussed the brief applications of the inverse vulcanized polysulfides to remove heavy metal wastewater and emphasized the modified synthesis processes for enhanced uptake ratios. The characteristics of polysulfide adsorbents, which play a vital role during the removal process are highlighted with a proper discussion of the interaction between metal ions and polysulfides. The review paper concludes with remarks on the future outlook of these low-cost adsorbents with high selectivity to heavy metals. These polysulfide adsorbents can be prepared using a wide variety of crosslinker monomers including organic hydrocarbons, cooking oils, and agro-based waste materials. They have shown good surface area and excellent metal-binding capabilities compared to the commercially available adsorbents. Proper postmodification processes have enabled the benefits of repetitive uses of the polysulfide adsorbents. The improved surface area obtained by appropriate choice of crosslinkers, modified synthesis techniques, and regeneration through post-modification has made inverse vulcanized polysulfides capable of removing. [Display omitted] • Inverse vulcanized polysulfides (IVPs) can tackle heavy metal wastewater pollution. • IVPs are prepared in a simple technique and can be scaled up to kilograms or tones. • Surface area can be increased by carbonization, electrospinning, salt porogen, etc. • Choice of crosslinking monomers is important for a higher adsorption rate. • Postmodification can prevent leaching and introduce multiple uses of adsorbents. [ABSTRACT FROM AUTHOR]