Application of red mud as both neutralizer and catalyst in supercritical water oxidation (SCWO) disposal of sewage sludge

RSC Advances ◽  
2016 ◽  
Vol 6 (59) ◽  
pp. 54202-54214 ◽  
Author(s):  
Hongzhen Chen ◽  
Guangwei Wang ◽  
Yuanjian Xu ◽  
Zhong Chen ◽  
Fengjun Yin
Keyword(s):  
Sewage Sludge ◽  
Supercritical Water ◽  
Red Mud ◽  
Water Oxidation ◽  
Supercritical Water Oxidation

Red mud was used in the supercritical water oxidation (SCWO) disposal of sewage sludge, not only as a neutralizer for acidic substances produced in situ, but also as a catalyst for decomposition of pollutants.

Green process for supercritical water oxidation of sewage sludge with red mud as CO2 absorbent

2016 ◽  
Vol 4 (3) ◽  
pp. 3065-3074 ◽  
Author(s):  
Hongzhen Chen ◽  
Guangwei Wang ◽  
Yuanjian Xu ◽  
Zhong Chen ◽  
Fengjun Yin
Keyword(s):  
Sewage Sludge ◽  
Supercritical Water ◽  
Red Mud ◽  
Water Oxidation ◽  
Supercritical Water Oxidation ◽  
Green Process ◽  
Co2 Absorbent

scholarly journals Supercritical water oxidation of phenol and process enhancement with in situ formed Fe2O3 nano catalyst

2021 ◽  
Author(s):  
Ammar Al-Atta ◽  
Farooq Sher ◽  
Abu Hazafa ◽  
Ayesha Zafar ◽  
Hafiz M. N. Iqbal ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Supercritical Water ◽  
Water Oxidation ◽  
Phenol Oxidation ◽  
Average Particle ◽  
Supercritical Water Oxidation ◽  
Study Objective ◽  
Cod Reduction ◽  
Nano Catalyst

AbstractDuring the past few decades, the treatment of hazardous waste and toxic phenolic compounds has become a major issue in the pharmaceutical, gas/oil, dying, and chemical industries. Considering polymerization and oxidation of phenolic compounds, supercritical water oxidation (SCWO) has gained special attention. The present study objective was to synthesize a novel in situ Fe2O3nano-catalyst in a counter-current mixing reactor by supercritical water oxidation (SCWO) method to evaluate the phenol oxidation and COD reduction at different operation conditions like oxidant ratios and concentrations. Synthesized nano-catalyst was characterized by powder X-ray diffraction (XRD) and transmission electron microscope (TEM). TEM results revealed the maximum average particle size of 26.18 and 16.20 nm for preheated and non-preheated oxidant configuration, respectively. XRD showed the clear peaks of hematite at a 2θ value of 24, 33, 35.5, 49.5, 54, 62, and 64 for both catalysts treated preheated and non-preheated oxidant configurations. The maximum COD reduction and phenol oxidation of about 93.5% and 99.9% were observed at an oxidant ratio of 1.5, 0.75 s, 25 MPa, and 380 °C with a non-preheated H2O2 oxidant, while in situ formed Fe2O3nano-catalyst showed the maximum phenol oxidation of 99.9% at 0.75 s, 1.5 oxidant ratio, 25 MPa, and 380 °C. Similarly, in situ formed Fe2O3 catalyst presented the highest COD reduction of 97.8% at 40 mM phenol concentration, 1.0 oxidant ratio, 0.75 s residence time, 380 °C, and 25 MPa. It is concluded and recommended that SCWO is a feasible and cost-effective alternative method for the destruction of contaminants in water which showed the complete conversion of phenol within less than 1 s and 1.5 oxidant ratio.

Phosphate recovery from sewage sludge in combination with supercritical water oxidation

2003 ◽  
Vol 48 (1) ◽  
pp. 185-190 ◽  
Author(s):  
K. Stendahl ◽  
S. Jäfverström
Keyword(s):  
Sewage Sludge ◽  
Supercritical Water ◽  
Water Oxidation ◽  
Organic Contaminants ◽  
Sodium Phosphate ◽  
Pure Water ◽  
Phosphate Solution ◽  
Supercritical Water Oxidation ◽  
Digested Sludge ◽  
Sodium Phosphate Solution

Supercritical Water Oxidation (SCWO) is an innovative and effective destruction method for organics in sewage sludge. The SCWO process leaves a slurry of inorganic ash in a pure water phase free from organic contaminants, which opens possibilities for a simple process to recover components like phosphates from the sewage sludge. In a continuous pilot plant for the SCWO process digested sludge has been treated. The ash has been extracted in lab scale with both caustic and acids in order to recover phosphates. By leaching the ash with caustic, 90% of the phosphorus could be separated as a sodium phosphate solution. By treating the sodium phosphate solution with lime, calcium phosphate was precipitated and caustic recovered and circulated back to the leaching process.

Design of the first pilot scale plant of China for supercritical water oxidation of sewage sludge

2012 ◽  
Vol 90 (2) ◽  
pp. 288-297 ◽  
Author(s):  
Donghai Xu ◽  
Shuzhong Wang ◽  
Xingying Tang ◽  
Yanmeng Gong ◽  
Yang Guo ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Supercritical Water ◽  
Water Oxidation ◽  
Pilot Scale ◽  
Supercritical Water Oxidation
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