The impact of recycling alum-humic-floc (AHF) on the removal of natural organic materials (NOM): Behavior of coagulation and adsorption

Ya-tong, XU; Chen, Ting; Liu, Zhiquan; Zhu, Shijun; Cui, Fuyi; Shi, Wenxin

doi:10.1016/j.cej.2015.09.069

Cited by 38 publications

(14 citation statements)

References 29 publications

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“…According to our research, different coagulation mechanisms could influence breakage and regrowth process, because the surface properties of flocs changed. Charge neutralization, sweep coagulation, and bridging are the commonly encountered mechanisms in the flocculation (Xu et al 2016b). Charge neutralization becomes a major mechanism for polyelectrolytes where significance particles of surface sites with charge opposite to that of polymer functional groups are present, like PACl.…”

Section: Introductionmentioning

confidence: 99%

Breakage and regrowth of flocs formed by sweep coagulation using additional coagulant of poly aluminium chloride and non-ionic polyacrylamide

Nan

Yao

Chen

et al. 2016

Environ Sci Pollut Res

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The breakage and regrowth of flocs formed by sweep flocculation were investigated on different flocculation mechanisms using additional dosage coagulant of poly aluminium chloride (PACl) and non-ionic polyacrylamide (PAM) to explore the reversibility after floc breakage. The optimal dosage of PACl was 0.15 mM (as alum), and zeta potential exceeding 1 mV meant that sweep flocculation was dominant in the pre-flocculated process. Re-coagulation efficiency increased with additional coagulants dosing, and sedimentation rates of flocs re-formed by small additional dosage of non-ionic PAM are faster than that of flocs re-formed by additional PACl. For additional inorganic coagulant (PACl) during regrowth processes, few negatively charged particles that existed in water sample restricted the effect of charge neutralization. An amorphous aluminum hydroxide precipitation could re-activate the weaker points on the broken floc surface, but regrown flocs have loose structure indicating worse settleability. For additional non-ionic PAM dosing, lower dosage showed large values of fractal dimension and average size, probably due to that unfolded curly molecular chain and exposed amide groups of non-ionic PAM which provide superb conditions for amide group interacting with particles. The use of non-ionic PAM in flocculation has advantage of being more effective than the cationic PACl, probably because it may avoid the re-stabilization of broken flocs by polymer adsorption driven by electrostatic attraction. Hence, appropriate dosing of PAM after breakage could improve the flocs characteristics with large size and compact structure.

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Section: Introductionmentioning

confidence: 99%

Breakage and regrowth of flocs formed by sweep coagulation using additional coagulant of poly aluminium chloride and non-ionic polyacrylamide

Nan

Yao

Chen

et al. 2016

Environ Sci Pollut Res

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“…As stated above, Xu et al . () found that the coagulated flocs formed by the alum sludge PACl were larger than those of PACl alone. Therefore, the higher limit flux obtained in our case after a coagulation with alum sludge can be explained by the fact that the flocs formed during the coagulation process with alum sludge are larger and more compact than those resulted after a coagulation with Al 2 (SO 4 ) 3 .…”

Section: Resultsmentioning

confidence: 94%

“…Floc characteristics are of a great importance because they generally affect contaminants removal and particle behaviour, particularly with regards to collision and, settling rates (Johnson et al 1996). When treating HA-kaolin synthetic water, Xu et al (2016) found that the coagulated flocs formed after the re-growth phase by the alum sludge produced under jar test coagulation conditions and the combined alum sludge with PACl were larger in size and more compact than those by PACl alone; this might result in a better settling performance. This is highly advantageous in terms of capital cost and footprint because a shorter retention time combined with larger and more compact flocs result in smaller and more compact flocculation and sedimentation units (Boller & Blaser 1998).…”

Section: Introductionmentioning

confidence: 99%

Assessment of coagulation‐ultrafiltration performance for the treatment of primary wastewater using alum sludge

Mazari

Abdessemed

Szymczyk

et al. 2018

Water & Environment J

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The main purpose of this research was to develop an effective and inexpensive pretreatment for ultrafiltration (UF) membrane process in order to treat a primary effluent for its reuse in several applications by avoiding biological treatment. For that the impacts of reuse alum sludge liquid recovered by the drinking water treatment plant of Boudouaou (Algiers area) has been examined on the water quality in coagulation–sedimentation processes. The tests were carried out on a primary effluent of wastewater treatment plant. The elemental analysis by x‐ray fluorescence showed that the tested sludge is composed mainly of Al2O3 (41%) and SiO2 (44%). The efficiency of alum sludge as primary coagulant was compared with a conventional metal‐ion coagulant (fresh alum) using a jar test apparatus for simultaneous removals of turbidity, UV254 and chemical oxygen demand (COD). For dose of 30 mg Al/L, the sludge was effective as primary coagulant for removing the turbidity, COD and UV254.

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“…This is consistent with previous studies. 31,32 Adsorption by activated carbon Adsorption isotherms As seen in Table 2, the experimental data for DOC adsorption by activated carbon shows a better fitting to the Freundlich model…”

Section: Dom Fractionation In Sro Concentratementioning

confidence: 93%

Potential of coagulation/GAC adsorption combined with UV/H₂O₂ and ozonation for removing dissolved organic matter from secondary RO concentrate

Zhang

Lin

et al. 2018

J of Chemical Tech & Biotech

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BACKGROUD Organic contaminants in secondary reverse osmosis (SRO) concentrate pose a severe threat to the ecosystem, due to their potential toxicity. In this study, potential of coagulation/granular activated carbon (GAC) adsorption combined with UV/H2O2 and ozonation for removing organic matter from industrial secondary RO concentrate was systematically investigated. RESULTS Coagulation with 2.0 mmol L−1 FeCl3 yielded 40% removal of dissolved organic carbon (DOC), while adsorption with 5 g L−1 GAC could boost the removal efficiency up to 78.2%. Fractionation results showed that both coagulation and GAC adsorption favored hydrophobic organics. UV/H2O2 oxidation was capable of removing 87.4% of DOC, which outperformed ozonation (58.2%). UV/H2O2 and ozonation showed similar behavior in dissolved organic matter (DOM) degradation: a portion of hydrophobic organics were first transformed into hydrophilic fractions prior to final mineralization. Conclusion Coupling of GAC as post‐treatment with a UV/H2O2 process yielded 97.9% removal of DOC and the corresponding electrical energy per order (EE/O) was decreased from 66.7 to 35.8 kWh m−3. Consequently, a simple UV/H2O2 and GAC hybrid process was proposed to be a suitable method for removing DOM from SRO concentrate. © 2018 Society of Chemical Industry

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The impact of recycling alum-humic-floc (AHF) on the removal of natural organic materials (NOM): Behavior of coagulation and adsorption

Cited by 38 publications

References 29 publications

Breakage and regrowth of flocs formed by sweep coagulation using additional coagulant of poly aluminium chloride and non-ionic polyacrylamide

Breakage and regrowth of flocs formed by sweep coagulation using additional coagulant of poly aluminium chloride and non-ionic polyacrylamide

Assessment of coagulation‐ultrafiltration performance for the treatment of primary wastewater using alum sludge

Potential of coagulation/GAC adsorption combined with UV/H₂O₂ and ozonation for removing dissolved organic matter from secondary RO concentrate

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The impact of recycling alum-humic-floc (AHF) on the removal of natural organic materials (NOM): Behavior of coagulation and adsorption

Cited by 38 publications

References 29 publications

Breakage and regrowth of flocs formed by sweep coagulation using additional coagulant of poly aluminium chloride and non-ionic polyacrylamide

Breakage and regrowth of flocs formed by sweep coagulation using additional coagulant of poly aluminium chloride and non-ionic polyacrylamide

Assessment of coagulation‐ultrafiltration performance for the treatment of primary wastewater using alum sludge

Potential of coagulation/GAC adsorption combined with UV/H2O2 and ozonation for removing dissolved organic matter from secondary RO concentrate

Contact Info

Product

Resources

About

Potential of coagulation/GAC adsorption combined with UV/H₂O₂ and ozonation for removing dissolved organic matter from secondary RO concentrate