Preparation and coagulation efficiency of polyaluminium ferric silicate chloride composite coagulant from wastewater of high-purity graphite production

Niu, Xiaoxia; Li, Xi-Li; Zhao, Jihong; Ren, Yigang; Yang, Yan

doi:10.1016/s1001-0742(10)60537-2

Cited by 41 publications

(16 citation statements)

References 18 publications

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“…Numerous studies have been published in order to assess the effect of OH/Fe molar ratio on the coagulation behaviour of PFC. All these studies have proven that the effectiveness of PFC solutions not only depends on the iron dosage and OH/Fe molar ratio, but also on the type of wastewater due to its effect on the resultant pH after PFC is added. This fact means that the same OH/Fe composition and dosage can lead to different results, depending on the wastewater studied.…”

Section: Resultssupporting

confidence: 93%

Treatment of an agrochemical wastewater by combined coagulation and Fenton oxidation

Molina

Pariente

Rodriguez

et al. 2014

J of Chemical Tech & Biotech

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BACKGROUND: Growing environmental concern about the presence of pesticides in water demands their removal, particularly in industrial wastewater effluents. These streams are characterized by high content of organic colloidal matter. Physicochemical treatments based on the combination of coagulation-flocculation processes have been well studied. An integral treatment of a non-biodegradable agrochemical wastewater has been tackled by physicochemical treatment with polyferric chloride (PFC) followed by a homogeneous Fenton oxidation process. RESULTS:The potential coagulation and flocculation properties of PFC were evaluated for PFC solutions of different OH/Fe molar ratios. TOC removal of 81% was obtained in the coagulation-flocculation pre-treatment under the best operating conditions. The Fenton process with moderate dosage of hydrogen peroxide and 90 ∘ C also provided an extra 37% TOC reduction. The sludge from the physicochemical process was successfully activated with KOH at 750 ∘ C, obtaining a highly microporous material of 1240 m 2 g −1 of surface area. CONCLUSION: This work proposes a cost-effective approach to the treatment of a non-biodegradable agrochemical wastewater, achieving overall TOC reduction of 88%. The iron-containing sludge generated in the primary physicochemical treatment when treated by thermal treatment provides a promising adsorbent.

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Section: Resultssupporting

confidence: 93%

Treatment of an agrochemical wastewater by combined coagulation and Fenton oxidation

Molina

Pariente

Rodriguez

et al. 2014

J of Chemical Tech & Biotech

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“…Similar trends can be observed for the COD and UV 254 removal and the optimal (Al + Fe)/Si molar ratio was identified as 13:1. These results were in good agreement with the relevant previous research and may be attributed to the degree of polymerization of PAFSiC with different (Al + Fe)/Si molar ratios. By the dissolution of aluminum salt, iron salt and polysilicate, various reactions occurred immediately, and hydroxyl aluminum ferrous silicate species was formed with Al‐O‐Si and Fe‐O‐Si bonds, which could to some extent retard the hydrolysis‐polymerization of Al and Fe.…”

Section: Resultssupporting

confidence: 93%

“…The characterization and coagulation behaviour of these coagulants were also studied. But investigations of the synthesis and optimization of PAFSiC from coal gangue are limited . To the best of our knowledge, the fabrication of a composite coagulant of PAFSiC customized for the tertiary‐treatment of coking wastewater has not been reported.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and optimization of a novel poly‐silicic metal coagulant from coal gangue for tertiary‐treatment of coking wastewater

Liu

Wang

et al. 2017

J of Chemical Tech & Biotech

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BACKGROUND Bio‐treated coking wastewater is difficult to treat further, mainly due to the bio‐refractory organic content. Coal gangue is the largest solid waste in China and it contains large amounts of aluminum, iron and silicon. This study attempts to recover the waste in coal gangue as a novel poly‐silicic metal coagulant for bio‐treated coking wastewater treatment. RESULTS The poly‐silicic metal coagulant was synthesized from coal gangue under different conditions. Fourier transform infrared spectroscopy, X‐ray diffraction and scanning electron microscopy confirmed that both amorphous and crystalline phases were present in the samples and new chemical bonds such as Si–O–Al and Si–O–Fe were formed. The results show that the composite coagulant was effective for organic removal from the bio‐treated coking wastewater and the optimal Al/Fe/Si molar ratios were Al/Fe = 3 and (Al + Fe)/Si = 13. The removal of organics exhibits a parabolic curve as the coagulant dosage increases. However, the optimal dosage (125 mg L‐1) for organic removal was not equal to the isoelectric point (100 mg L‐1). Furthermore, SEM images showed that the flocs start to disintegrate at a dosage of 150 mg L‐1, leading to deteriorating sludge settling. CONCLUSIONS It is feasible to fabricate poly‐silicic metal coagulants for coking wastewater treatment by using coal gangue as the raw material. The removal of the bio‐refractory organics by the composite coagulant was attributed to the combined effects of charge neutralization, bridge adsorption and the net capturing. © 2017 Society of Chemical Industry

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“…So 25 mg L −1 was our optimal dosage. This result was also in agreement with that by Niu et al [9]. .…”

Section: Orthogonal Test Designsupporting

confidence: 94%

“…Given COD removal performance described above and characteristics of chemical coagulants, the optimal coagulant combination for our study was selected as PAFC, for its great COD removal capacity as well as its non-toxic property. These results were in accordance with previous research, [9][10][11] which told an excellent capacity for PAFC as a coagulant. Aguilar et al [12] illustrated that PAM could aid coagulation by accelerating settling speed of colloidal particles for its large molar and electric density, which resulted in a slight increase of COD in slaughterhouse wastewater.…”

Section: Raw Water Qualitysupporting

confidence: 94%

Feasibility and optimization of wastewater treatment by chemically enhanced primary treatment (CEPT): a case study of Huangshi

Wang

et al. 2016

Chemical Speciation & Bioavailability

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Carbon and nutrients as well as suspended solids (SS) removal by chemically enhanced primary treatment (CEPT) were conducted in the Qingshan wastewater treatment plant in Huangshi, Hubei Province. Feasibility of this process for wastewater treatment were investigated in detail by comparing the removal performance of three inorganic chemical coagulants (polyaluminium chloride, polyaluminium ferric chloride [PAFC] and poly ferric sulfate) individual or couple with poly acrylamide, optimizing the conditions during CEPT by both single factor analysis and orthogonal test designs. The results of this study demonstrated that CEPT turned out to be an effective method for wastewater treatment, with PAFC as the optimal coagulant, which showed preeminent removal capacity for chemical oxygen demand, total phosphorus and SS. The optimal working condition could be at pH 7.0, settling time 15 min, and velocity gradient of 174.80 and 15.56 s −1 for mixing and reaction phase respectively. While the coagulant dosage depends on raw water attributes, which had a decisive effect on CEPT treatment performances. However, the three coagulants behaved poorly in nitrogen removal.

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Preparation and coagulation efficiency of polyaluminium ferric silicate chloride composite coagulant from wastewater of high-purity graphite production

Cited by 41 publications

References 18 publications

Treatment of an agrochemical wastewater by combined coagulation and Fenton oxidation

Treatment of an agrochemical wastewater by combined coagulation and Fenton oxidation

Synthesis and optimization of a novel poly‐silicic metal coagulant from coal gangue for tertiary‐treatment of coking wastewater

Feasibility and optimization of wastewater treatment by chemically enhanced primary treatment (CEPT): a case study of Huangshi

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