Advanced Materials Research Vol. 800

Abstract: The recovery of polyvinyl alcohol (PVA) by flocculation method is investigated. The sodium polyphosphate is used as flocculating agent. The sodium sulfate produced by the relation between sodium hydroxide and sulfuric acid is used as salting-out agent. The sodium carbonate is used as coagulating agent. The optimal component ratio of flocculating agent, salting-out agent, coagulating agent is obtained by orthogonal experiment. The absorbency of PVA solution is selected as a reference index. PVA content was determined with spectrophotometry. The structure of recovered PVA is analyzed by infrared spectrum. The results show that the PVA recovery rate is as high as 96.5%.Keywords: flocculation method; PVA; sodium polyphosphate; orthogonal experiment;

Abstract: Due to the traditional wastewater treatment method has disadvantages of low efficiency and high-energy, in allusion to these problems, this paper proposed a kind of intelligent wastewater treatment control system based on biological aerated filter (BAF), combined with strong function of SIEMENS S7-300 PLC. It introduced the principle of BAF, configuration scheme, hardware and software design. It can track operation parameters on line, failure diagnosis and alarm, so as to realize intelligent control. Through the actual operation analysis and simulations, show the system runs stably, easy to control and manage, better achieves the quality standard of urban reuse water.

Abstract: Oxidative degradation of ethylenediaminetetraacetic acid (EDTA) in aqueous solution at room temperature and pressure by the bimetallic Al-Fe/O₂ process, which was verified by the addition of benzoic acid as ·OH scavenger and the detection of para-hydroxybenzoic acid, was investigated. The results showed that the removal efficiency of EDTA, TOC and TN could be about 98%, 77.5% and 43% respectively after 3h reaction when the initial pH was 5. The effects of initial pH, concentration of EDTA, mass ratio of Al⁰ and Fe⁰ and Al-Fe loading were also investigated. Significantly, the bimetallic Al-Fe process exhibited higher reactivity than monometallic Fe⁰/Al⁰ process for the degradation of EDTA when the mass ratio of Al⁰ and Fe⁰ ranged from 0.11 to 2.97.

Abstract: The present work focuses on improving the treating efficiency of micro-electrolysis, to solve the problem of passivation and compaction, thereby reducing the investment cost, based on researching the characteristics of treating wastewater through micro-electrolysis, a new method, cavitation-impinging stream micro-electrolysis, is presented, then designing a cavitation- impinging stream micro-electrolysis reactor and analyzing the advantageous features of cavitation- impinging stream micro-electrolysis technology in treating organic wastewater.

Abstract: The efficacy of the UV-H₂O₂ treatment to degrade the antibiotic chloramphenicol (CHL) was investigated at 20 °C using a low-pressure mercury lamp as UV source. A two-level factorial design was used to study the effects of initial CHL (c₀ = 4080 mg L¹) and H₂O₂ (h₀ = 2050 mM) concentrations, reaction time (t = 3070 min) and irradiance level (I = 400800 μW cm²) on CHL degradation. Under the best conditions (c₀ = 40 mg L¹, h₀ = 20 mM, t = 70 min, I = 800 μW cm²), almost 96% of the antibiotic was degraded. No residual antibiotic activity was detected in the treated solution, thereby confirming the efficacy of the UV-H₂O₂ process.

Abstract: Design a practical and effective hydrodynamic cavitation experimental apparatus, the establishment of cavitation radical scavenging method, the use of methylene blue to study the relationship of the hydroxyl radical production and cavitation cavitation intensity, the study of the various factors of cavitation radical production, and to explore optimal cavitation strengthen the conditions. Hydrodynamic cavitation kill algae has some effect, there will be varying degrees of decline in the concentration of algae. The hydrodynamic cavitation algae suppression and damaging effects.

Abstract: Humic acids (HA) that are one of the major organic components in natural water play an important role in water treatment because they can interact with metals, trace organics, and chlorine while generating toxic complexes and by-products. In this work, photocatalytic degradation of HA and its kinetic behavior were investigated in a photocatalytic microfiltration (MF) system, along with evaluation of membrane permeability at different fluxes. The mechanisms of adsorption and desorption of HA on TiO₂ surfaces were elucidated with adsorption isotherm tests of HA before and after photocatalysis of humic water. The kinetic parameters for humic acids, k (rate constant) and K (equilibrium adsorption coefficient) of the Langmuir-Hinshelwood equation, were obtained based on mass balances in continuous stirred tank reactor (CSTR) operations. Regarding membrane fouling, it was assumed that the rate of degree of fouling is disproportional to the fouling resistance. It was found that the fouling rate constant started increasing substantially when the flux increased to a level of greater than 50 L/m²-h. This indicated that the photocatalytic MF system should be operated at a flux below the critical value to prevent serious membrane fouling.

Abstract: The High Performance Compact Reactor (HCR) was applied in the pilot plant, and the influence of jet volume, residence time and pollution loads on the pollutant removal efficiency was investigated. The results show that HCR system start operating faster processing Shale Oil Wastewater, 3.1m³ / h of jet volume was the best and the optimal residence time of 40min. At the same time, HCR process has stronger anti-shock loading capability and anti-pollution loading capability.

Abstract: Carboxymethyl cellulose (CMC) sodium with negatively charged character was used as functional layer of polyetherimide (PEI) ultrafiltration membrane. The preparation parameter such as CMC concentration, cross-linking agent concentration and curing temperature are studied in detail. When the composite membrane was prepared under optimized conditions and tested at 0.4 MPa and 20 °C, the flux of the composite NF membrane was about 3 L/m²h and the MgCl₂ rejection of it was about 87%. The composite membrane showed classical negatively charged membrane character which had higher rejection to high valent anion.

Abstract: For a better application of multi-soil-layering (MSL) system to treat polluted river water flowing into Dianchi Lake in different surface loads, six systems are set on the river bank of New Yunliang River for a four-month-experiment. The surface loads are set as 800L/m²•d, 1000 L/m²•d, 1500 L/m²•d, 2000 L/m²•d, 3000 L/m²•d and 4000 L/m²•d, respectively. When the surface load is 1000L/m²•d, the average removal rate of COD, TN, NH₄⁺-N and TP are 74.8%, 28.9%, 88.5% and 87.0% respectively; when the surface load is 1500 L/m²•d, the average removing rate of COD, TN, NH₄⁺-N and TP are 72.4%, 20.2%, 83.9% and 84.1% respectively. The surface load has a big influence on the removal of COD, NH₄⁺-N and TP. Due to insufficient denitrification, the removing rate of TN is comparatively low. With a view to the removing effect and load reduction and the long-term operation conditions of the system, the most appropriate surface load is between 1000~1500 L/m²•d.