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- Nanofibrillated cationic cellulose derivatives as flocculants for domestic wastewater treatmentPublication . Ribau Teixeira, Margarida; Ismail, Abdullah; Medronho, Bruno; Alves, Luís; Pedrosa, Jorge F.S.; Ferreira, Paulo J.T.; Serrão Sousa, Vânia; Rosa Da Costa, AnaNatural-based coagulants have emerged as a reliable option to implement more sustainable operations and management of wastewater treatment plants. This work aims at evaluating the use of cationic nanofibrillated celluloses (cNFC) as novel bio-based flocculants to treat domestic wastewaters by the most widely employed treatment process – coagulation/flocculation. Two cNFC samples were prepared with different charge densities and tested as coagulant/flocculants using different water characteristics. The effect of cNFCs was studied by measuring the residual turbidity and dissolved organic carbon. The aggregation mechanism and kinetics of flocculation were also evaluated. Results show that cNFC can be used as an efficient flocculant to treat medium and high DOC waters since they considerably reduce turbidity (turbidity removals varied between 66.0 % and 85.7 % for the waters and cNFCs tested) without increasing dissolved organic carbon. Instead, cNFC removed dissolved organic carbon from domestic wastewaters (between 22.1 % and 65.5 % of DOC removals for the waters and cNFCs tested), which is a novel remarkable finding and a step forward in this knowledge area. High density charged cNFC revealed superior removal capacity at lower doses than the commercial coagulant FeCl3.
- Investigating the adsorption potential of coconut coir as an economical adsorbent for decontamination of lanthanum ion from aqueous solutionPublication . Javed, Tariq; Kausar, Fahmida; Zawar, Muhammad Danish; Khalid, Nasir; Thumma, Anusha; Ismail, Abdullah; Alzaidy, Asaad H.; Abed, May Jaleel; Jasim, Layth S.; Taj, Muhammad Babar; Tirth, Vineet; Haider, Muhammad NoumanCoconut coir was explored as economical sorbent for the adsorptive removal of lanthanum ion (La3+) from aqueous media. Both column and batch studies were conducted to assess the effective removal of La3+ on coconut coir by optimizing different adsorption variables such as bed height, flow rate, pH, adsorbent dosage, shaking time, initial metal concentration, and temperature. Characterization of coconut coir was carried out by scanning electron microscopy (SEM), FT-IR, and BET studies prior and subsequent to adsorption. The effective removal of La3+ was defined in certain media by the pHzpc, which was found to be 5.7 +/- 0.1. The optimum 94.04 +/- 0.2% adsorption of La3+ on coconut coir was observed by shaking 4 cm3 of 90 mol/L solution of La3+ with 0.3 g adsorbent dose for 10 min at neutral pH. The Langmuir adsorption capacity was found to be qe=2.88 +/- 0.02 mg g-1 and Freundlich adsorption capacity was KF =0.1294 +/- 0.03 mg g-1. The pseudo-second-order kinetic and Langmuir isotherm models provided an ideal fit for the adsorption process. The column analysis also showed direct correlation of bed height and initial metal concentration with % adsorption, while % removal decreased as flow rate increased. The high regression coefficient values confirm that the BDST model is in line with the test data. Van't Hoff equation proved the spontaneous endothermic process. Effect of external ions and desorption are also studied. The results suggest that coconut coir is a cost effective and efficient bio-sorbent for La3+ ion adsorption from aqueous solution.