Combined physical and chemical activation of sludge-based adsorbent enhances Cr(Ⅵ) removal from wastewater

Zhang, Liguo; Pan, Jingshi; Liu, Lei; Song, Kang; Wang, Qilin

doi:10.1016/j.jclepro.2019.117904

Cited by 26 publications

(9 citation statements)

References 34 publications

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“…A study on urea NaOH-modified carbonized sewage sludge effectively removed Cr 6+ in water with a maximum adsorption capacity of 15.3 mg g −1 at 2.5 pH and temperature of 25 • C. The adsorption best fitted with the Langmuir isotherm model and pseudo-second-order model. The study also found that over 95% removal efficiency of Cr 6+ could be obtained by regenerating the adsorbent with NaOH until five regeneration cycles [113].…”

Section: Sewage Sludgementioning

confidence: 79%

“…Nevertheless, the adsorption of Cr 6+ into NaOH and urea-treated carbonized sewage sludge has been maximum in the acidic medium (pH 1-2.5) in a range of pH 1 to 8 at 25 • C due to the protonation of the adsorbent surface, making it positively charged at low pH, which enhances the electrostatic interaction of chromate ions [113]. A study by Wang et al [107] found that Cr 6+ adsorption into polyethyleneimine-modified sewage sludge has also decreased with the increase in pH from 3 to 8 due to changes in the adsorbent and Cr 6+ .…”

Section: Effect Of Ph On Adsorption Of Heavy Metalsmentioning

confidence: 99%

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Sustainable Approaches for Wastewater Treatment: An Analysis of Sludge-Based Materials for Heavy Metal Removal from Wastewater by Adsorption

Rajakaruna,

Sewwandi,

Najim

et al. 2023

Sustainability

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A comprehensive study incorporating results from different findings related to heavy metal removals from wastewater using sludge as an absorbent will assist researchers and practitioners in planning wastewater treatment processes. This study aims to provide a comprehensive foundation on the potential of using sludge-based materials to remove heavy metals from wastewater based on recent studies. The physicochemical properties of sludge and the nature of metal ions have significantly contributed to the adsorption of heavy metals into sludge-based materials. Many researchers found the effects of pH, temperature, initial heavy metal concentrations, contact time, and adsorbent dose on the adsorption characteristics of heavy metals into sludge-based materials. Isotherm, kinetic, and thermodynamic studies have explained the mechanism of heavy metal adsorption by sludge-based materials. The effectiveness of regeneration of sludge-based adsorbents has been investigated by some researchers, providing an environmentally friendly solution to remove heavy metals from wastewater. It was found that less attention has been paid to metal recovery and recycling of sludge-based adsorbents, which indicates the need for future studies to enhance the reusability of sludge in wastewater treatment. Moreover, many studies have been conducted as lab-scale experiments on heavy metal adsorption from aqueous solutions using sludge-based adsorbents, leaving a research gap for future studies to focus on the removal of heavy metals from actual wastewater at field scale.

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Section: Sewage Sludgementioning

confidence: 79%

Section: Effect Of Ph On Adsorption Of Heavy Metalsmentioning

confidence: 99%

Sustainable Approaches for Wastewater Treatment: An Analysis of Sludge-Based Materials for Heavy Metal Removal from Wastewater by Adsorption

Rajakaruna,

Sewwandi,

Najim

et al. 2023

Sustainability

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“…This process allows C.O.D. and color removal from textile wastewater in a single step without additional physicochemical treatment [42].…”

Section: Thismentioning

confidence: 99%

A Review of Bacterial Degradation of Azo Dyes

Alzain,

Kalimugogo,

Hussein

2023

Int J Res Rev

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Biodegradation of synthetic dyes using different bacteria is becoming an accepted approach for treating Azo dye wastewater to mitigate many environmental problems. Azo dye has a negative impact on the environment by increasing biochemical oxygen demand (B.O.D.) and chemical oxygen demand (C.O.D.). The Biodegradation of azo dyes by different bacteria was evaluated. Biodegradation of synthetic dyes not only results in the decolorization of the dyes but also in the disintegration of the dye molecules into smaller and simpler parts. Decolorization of the dye arises when the chromophoric center of the dye is slashed. Various microorganisms, including fungi, bacteria, yeasts, and algae, have been used to decolorize and Degradation of synthetic dyes. Bacterial decolorization is usually faster than fungal decolourization. It is well known that bacteria degrade azo dyes reductively under anaerobic circumstances to colorless aromatic amines, which are carcinogenic compounds. These colorless aromatic amines must also be degraded because they may be toxic, mutagenic, and carcinogenic to humans and animals Bacteria are capable of removing dyes by adsorption and absorption. Biosorption rates are directly matched with the composition of heteropolysaccharides and the cell wall lipids. Dead cells are more useful in Biosorption than living cells because they do not need nutrients and can be stockpiled for a long time. The azoreductases are considered to be the most potent group of enzymes active in the Biodegradation of synthetic azo dyes. They accomplish the reductive cleavage of synthetic azo dyes bonds. Laccases enzymes become more interesting and have more focus recently due to their ability in generating much lower toxic aromatic amines. Laccases do not need other cofactors. Many factors affecting the process are temperature, pH, salinity, dye concentration, and Bioremediation in aerobic and anaerobic environments. Keywords: Biodegradation, azo dyes, biochemical oxygen demand (B.O.D.), chemical oxygen demand (C.O.D.), bacterial enzymes and Bacterial Laccases enzymes.

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“…However, in the scientific literature, the studies on biochar for water treatment are mainly based on laboratory scenarios [34][35][36][37], and the operating conditions for a large scale certainly need to be investigated [38]. Furthermore, the adsorption of individual pollutants in synthetic aqueous solutions has been studied (e.g., phosphate [35], copper [36], and hexavalent chromium [37]). This methodology is not representative of real situations, in which biochar should be applied to complex waters simultaneously rich in different pollutants and interferents.…”

Section: Introductionmentioning

confidence: 99%

Survey on Lombardy Region Wastewater Effluents and Application of Biochar from Biological Sewage Sludge for Wastewater Treatment

Collivignarelli,

Caccamo,

Bellazzi

et al. 2023

Water

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Due to decreasing rainfall, drought is an environmental problem becoming even more alarming every year. The direct reuse of treated wastewater (WW), in compliance with current legislation, can be one of the applicable solutions to deal with water scarcity. In this study, an analysis of wastewater treatment plants (WWTPs) (>400 population equivalent) in the Lombardy region (Northern Italy) was performed to identify the most critical parameters in their effluents (total and ammonia nitrogen, and phosphorous). Biochar filters, as final adsorption means for WWTP effluents, could improve water quality for direct reuse. Biochar from biological sewage sludge produced by an urban WWTP (130,000 population equivalent) was prepared via pyrolysis (350–650–950 °C) and chemical activation with KOH. In each preparation step, the material was analyzed to follow the physicochemical transformations. The removal efficiency of COD, N-NH4+, N-NO3-, and P from real WW was studied using batch adsorption tests. Pyrolysis at 650 °C + KOH activation guaranteed higher yields for N-NH4+ (32%), P (44%), and N-NO3− (66%) with a contact time in the batch test of 6 h for N-NH4+ and P, and 3 h for N-NO3−. Up to 50% COD removal was achieved in 6 h with 950 °C pyrolyzed + KOH-activated biochar.

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Combined physical and chemical activation of sludge-based adsorbent enhances Cr(Ⅵ) removal from wastewater

Cited by 26 publications

References 34 publications

Sustainable Approaches for Wastewater Treatment: An Analysis of Sludge-Based Materials for Heavy Metal Removal from Wastewater by Adsorption

Sustainable Approaches for Wastewater Treatment: An Analysis of Sludge-Based Materials for Heavy Metal Removal from Wastewater by Adsorption

A Review of Bacterial Degradation of Azo Dyes

Survey on Lombardy Region Wastewater Effluents and Application of Biochar from Biological Sewage Sludge for Wastewater Treatment

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