New insights into the cooperative adsorption behavior of Cr(VI) and humic acid in water by powdered activated carbon

Biological powdered activated carbon (BPAC) was incorporated with a microfiltration (MF, 0.2 μm pore size) system to remove the refractory organic matter contained in secondary sewage effluent. A synthetic secondary sewage effluent was used as influent in this study, containing both non-biodegradable organic substances (such as humic acid, lignin sulfonate, tannic acid and arabic gum powder) and biodegradable ones. These refractory organic materials were possibly degraded in contact with microorganisms for 20-27 days. Although humic acid and arabic gum were weakly adsorbed on the activated carbon, they could be effectively removed in the BPAC reactor. The TOC removal at a powdered activated carbon (PAC) concentration of 20 g/L was higher than at 0.5-2 g PAC/L (83% and 66-68%, respectively). The higher removal efficiency was due to the increased rejection at the membrane module in which most of the PAC was accumulated. More than 90% of non-biodegradable compounds removal (detected as E280 , UV absorption at 280 nm) occurred in the BPAC reactor. The biological growth parameter b/Y, used in system design, was estimated to be 0.017 d-1. Relatively high permeate flux of 1.88 m/d could be obtained even at higher PAC concentration of 20 g/L.

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The impact of humic acid on metaldehyde adsorption onto powdered activated carbon in aqueous solution

RSC Advances ◽

10.1039/c8ra06802j ◽

2019 ◽

Vol 9 (1) ◽

pp. 11-22 ◽

Cited By ~ 5

Author(s):

Zhuojun Li ◽

Yuchen Yang ◽

Ulises Jáuregui-Haza ◽

Zhengxiao Guo ◽

Luiza Cintra Campos

Keyword(s):

Aqueous Solution ◽

Activated Carbon ◽

Humic Acid ◽

Powdered Activated Carbon ◽

The Impact

Powdered activated carbon with abundant micropores and mesopores can effectively remove metaldehyde from aqueous solution in the presence of humic acid.

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TiO2Photocatalyst Nanoparticle Separation: Flocculation in Different Matrices and Use of Powdered Activated Carbon as a Precoat in Low-Cost Fabric Filtration

Advances in Materials Science and Engineering ◽

10.1155/2014/602495 ◽

2014 ◽

Vol 2014 ◽

pp. 1-12 ◽

Cited By ~ 5

Author(s):

Carlos F. Liriano-Jorge ◽

Ugur Sohmen ◽

Altan Özkan ◽

Holger Gulyas ◽

Ralf Otterpohl

Keyword(s):

Activated Carbon ◽

Humic Acid ◽

Photocatalytic Oxidation ◽

Low Cost ◽

Powdered Activated Carbon ◽

Widespread Application ◽

Fabric Filter ◽

Nanoparticle Separation ◽

Ph Range ◽

The Impact

Separation of photocatalyst nanoparticles is a problem impeding widespread application of photocatalytic oxidation. As sedimentation of photocatalyst particles is facilitated by their flocculation, the influence of common constituents of biologically pretreated wastewaters (NaCl, NaHCO3, and their combination with humic acid sodium salt) on flocculation was tested by the pipet method. Results showed that the impact of these substances on TiO2nanoparticle flocculation is rather complex and strongly affected by pH. When humic acid was present, TiO2particles did not show efficient flocculation in the neutral and slightly basic pH range. As an alternative to photocatalyst separation by sedimentation, precoat vacuum filtration with powdered activated carbon (PAC) over low-cost spunbond polypropylene fabrics was tested in the presence of two PAC types in aqueous NaCl and NaHCO3solutions as well as in biologically treated greywater and in secondary municipal effluent. PAC concentrations of≥2 g/L were required in order to achieve a retention of nearly 95% of the TiO2nanoparticles on the fabric filter when TiO2concentration was 1 g/L. Composition of the aqueous matrix and PAC type had a slight impact on precoat filtration. PAC precoat filtration represents a potential pretreatment for photocatalyst removal by micro- or ultrafiltration.

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