Coagulation–flocculation process with metal salts, synthetic polymers and biopolymers for the removal of trace metals (Cu, Pb, Ni, Zn) from municipal wastewater

Abstract

To ensure compliance with regulatory standards, it is important to examine the potential of treatment technologies to enhance trace metal removal from wastewater. This study investigated the effectiveness of coagulation-flocculation at removing trace metals from humus effluent with ferric chloride (FeCl 3), the synthetic polymer polyethyleneimine (PEI) and the biopolymers chitosan and floculan. Effluent samples were collected from a trickling filter treatment works operating in the UK and contained 21 ± 4 μg/L Cu, 0.8 ± 0.1 μg/L Pb, 4 ± 1 μg/L Ni and 43 ± 9 μg/L Zn. The influence of coagulant dosage and the velocity and time of the slow mixing stage were studied via a series of jar tests. Chitosan and PEI had a moderate effect on the removal of trace metals (≤ 35%). FeCl 3 removed 48% Cu, 56% Pb and 41% Zn at the optimised dose of 0.10 mg/L. At the optimised dose of 0.25 mg/L, floculan removed 77% Cu, 68% Pb and 42% Zn. The dominant mechanism for particle removal by FeCl 3 was enmeshment in the precipitates (i.e. sweep flocculation), whereas, for floculan, inter-particle bridging was the dominant removal mechanism. Overall, FeCl 3 and floculan were found to be most effective at removing trace metals from wastewater.

Hydrosoluble phosphonic acid functionalized poly(2‐ethyl‐2‐oxazoline) chelating polymers for the sorption of metallic cations

“…[7][8][9] Processes based on ions exchangers proved to be robust but led to limited selectivity. [10][11][12][13][14][15] Chemical precipitation 16,17 was also largely employed despite a limited recovery. Side to these processes, the use of membrane was a promising approach when coupled with hydrosoluble polymers bearing chelating agents.…”

Novel PVDF-PVP Hollow Fiber Membrane Augmented with TiO2 Nanoparticles: Preparation, Characterization and Application for Copper Removal from Leachate

“…Several techniques have been employed for the removal of copper from wastewater [ 14 , 15 , 16 , 17 ]. These techniques include adsorption [ 18 , 19 ], chemical precipitation [ 20 ], photocatalysis [ 21 ] coagulation-flocculation [ 22 ], and electrochemical treatment [ 23 ]. Most of these methods are energy consuming, require high operational and maintenance costs, and generate poisonous secondary sludge and liquid waste [ 24 ].…”

N-(((2-((2-Aminoethyl)amino)ethyl)amino)methyl)-4-sulfamoylbenzamide Impregnated Hydrous Zirconium Oxide as a Novel Adsorbent for Removal of Ni(II) from Aqueous Solutions: Optimization of Variables Using Central Composite Design

“…Several approaches have been utilized for removal of Ni(II) from water and wastewater, which include nanofiltration, 15 coagulation–flocculation, 16 electrocoagulation, 17 electroflotation, 18 ion exchange, 19 photocatalytic removal, 20 adsorption, 21 and so forth. Among these treatment technologies, adsorption is recognized as a highly potential process for removal of Ni(II) from wastewater.…”