Highly efficient treatment of real benzene dye intermediate wastewater by simple limestone and lime neutralization-coagulation with improved Fenton oxidation

Abstract

Multistage Fenton oxidation is a favored method for the treatment of benzene dye intermediate (BDI) wastewater, but the pH adjustments required after each stage of the Fenton process with a simple way is still a challenge. Limestone pretreatment and lime neutralization-coagulation were used to solve the problem in multistage Fenton process. First, we determined the optimal conditions of Fenton oxidation using the Box-Behnken response surface method. Limestone pretreatment before the multistage Fenton process allowed for simultaneous pH adjustment and 14.15% COD removal. Most notably, the lime cream neutralization-coagulation process effectively adjusted the pH after each stage of the Fenton process. The optimum CaO particle size, lime mass fraction, mixing time, and stirring speed were determined by orthogonal tests. COD removal (89.23%) was obtained when lime cream neutralization-coagulation was applied to the three-staged Fenton process, while only 58.57% COD removal was obtained by the unadjusted single-staged Fenton process. The COD and wastewater color were reduced from 10,600 mg/L and 12,200 multiples to 495 mg/L and 20 multiples, respectively, using the adjusted process. This improved method provides a promising cost-effective way to efficiently treat real BDI wastewater.

Fenton oxidation as pretreatment for biomass gasification condensate: cost and biomass inhibition evaluation

“…The removal rate of COD plateaued at 30% NSR and reached a maximum of 51% at H 2 O 2 dosage of 60% NSR. The removal efficiency of COD by Fenton reaction was efficiently improved through a multistage neutralization-coagulation process with limestone (Guo et al 2018). However, the precipitates must be treated as hazardous solid waste.…”

“…Advanced oxidation processes (AOPs) were widely applied to abate the organic pollutants, such as pharmaceutics, phenols, formaldehyde, dye intermediate in wastewater. (Muzyka et al 2015;Cetinkaya et al 2018;Guo et al 2018;Nidheesh et al 2021). The Fenton oxidation relies on the in-situ production of hydroxyl radical from hydrogen peroxide through catalysis by Fe 2þ at a low pH value.…”

BTEXS Removal From Aqueous Phase by MCM-41 Green Synthesis Using Rice Husk Silica

“…Different techniques and processes have been used to treat benzene and toluene-contaminated water and usually show different levels of success. Currently, conventional treatments include filtration [12], distillation [13], evaporation [14], reverse osmosis [15], and coagulation [16]. Although these techniques are particularly effective, some associated disadvantages such as high operating and maintenance costs and byproduct (such as toxic sludge), encourage researchers to find alternative therapies [17,18].…”