Comparison of different internal fixation implants in the treatment of talar neck fractures: A finite element analysis.

OBJECTIVES: This study aimed to analyze the biomechanics of cannulated screws (CS) with or without a lateral locking plate (LLP) in talar neck fractures through a finite element analysis. PATIENTS AND METHODS: The computed tomography image of the talus from a healthy volunteer (adult male) was used to reconstruct a three-dimensional talar model. The method for fixing talar neck fractures with CS and an LLP was planned using computer-aided design software. Afterward, the three-dimensional models of comminuted talar neck fractures were used to simulate fixation with anteroposterior parallel dual CS, single CS+LLP, and dual CS+LLP. Finally, finite element analysis was carried out to compare the outcomes of dual CS+LLP to those of single CS+LLP and to those of using dual CS alone. The displacement and von Mises stress values of the three groups with different internal fixation were analyzed. RESULTS: For a simple talar neck fracture, the lowest amount of displacement was obtained with CS+LLP (0.407 mm), while dual CS (0.459 mm) showed the highest amount of total displacement; the lowest amount of peak stresses was obtained with CS+LLP (5.38 MPa), while dual CS (8.749 MPa) showed the highest amount of total peak stresses. For a comminuted talar neck fracture, the lowest amount of displacement was obtained with CS+LLP (0.398 mm), while dual CS (0.408 mm) showed the highest amount of total displacement; the lowest amount of peak stresses was obtained with CS+LLP (129.9 MPa), while dual CS (205.9 MPa) showed the highest amount of peak stresses. CONCLUSION: Compared to the other two groups, the dual CS+LLP group had better biomechanics properties in the displacement and stress peak of the talus and implant. Thus, the use of dual CS+LLP fixation is recommended for the surgical treatment of comminuted talar neck fractures.

[Source Apportionment and Pollution Assessment of Soil Heavy Metal Pollution Using PMF and RF Model: A Case Study of a Typical Industrial Park in Northwest China].

Based on the concentration data of seven heavy metal elements[As, Cd, Cu, Pb, Hg, Ni, and Cr(Ⅵ)] in the surface soil of a typical industrial park in northwest China, the characteristics of heavy metal pollution in the industrial park were analyzed, and the ecological risk and pollution were evaluated using the potential ecological risk index and the index of geo-accumulation. The positive matrix factorization (PMF) model and random forest (RF) model were used for quantitative source analysis, and the emission data of sampling enterprises and empirical data of the source emission component spectrum were combined to identify the characteristic elements and determine the emission source category. The results showed that the heavy metals at all sampling points in the park did not exceed the second-class screening value of construction land in the soil pollution risk control standard for construction land (GB 36600-2018). However, compared with the local soil background values, five elements, excluding As and Cr, were enriched in different degrees, presenting slight pollution and moderate ecological risk (RI=250.04). Cd and Hg were the main risk elements of the park. The results of source analysis showed that the five main sources of pollution were fossil fuel combustion and chemical production sources (33.73%, 9.71%, total source contribution rate of PMF and RF, respectively; the same below), natural sources and waste residue landfill (32.40%, 40.80%), traffic emissions (24.49%, 48.08%), coal burning and non-ferrous metal smelting (5.43%, 0.11%), and electroplating and ore smelting (3.95%, 1.30%). The simulation R2 of the total variable of the two models were above 0.96, indicating that the models could predict heavy metals well. However, considering the actual situation of the number of enterprises in the park and roading density, the main pollution sources of soil heavy metals in the park should be industrial sources, and the simulation results of the PMF model were closer to the actual situation in the park.

Rare pattern of Maisonneuve fracture: A case report.

BACKGROUND: Maisonneuve fracture is a special type of ankle fracture that consists of proximal fibular fracture, a lesion of the inferior tibiofibular syndesmotic complex (interosseous ligament, anterior inferior tibiofibular ligament and posterior inferior tibiofibular ligament), and injury of the medial structure of the ankle (deltoid ligament tear or medial malleolar fracture). The accepted mechanism of Maisonneuve fracture is pronation external rotation according to the Lauge-Hansen classification. In this paper, we report a rare pattern of Maisonneuve fracture, which has the characteristics of both pronation external rotation ankle fracture and supination adduction ankle fracture. CASE SUMMARY: A 31-year-old female patient accidentally sprained her right ankle while walking 5 d before hospitalization in our hospital. The patient was initially missed in other hospitals and later rediagnosed in our outpatient department. Full-length radiographs of the lower leg revealed proximal fibula fracture, inferior tibiofibular joint separation, and medial malleolar fracture involving the posterior malleolus, which was also revealed on computed tomography scans. Magnetic resonance imaging revealed rupture of the anterior inferior tibiofibular ligament and anterior talofibular ligament. We diagnosed a rare pattern of Maisonneuve fracture with proximal fibular fracture, inferior tibiofibular joint separation, medial malleolar fracture and ruptures of the anterior inferior tibiofibular ligament and anterior talofibular ligament. The patient underwent open reduction and internal fixation in our hospital. A 6-mo postoperative follow-up confirmed a good clinical outcome. CONCLUSION: To our knowledge, this rare pattern of Maisonneuve fracture has not been previously described. The possible mechanism of injury is supination adduction combined with pronation external rotation. Careful analysis of the injury mechanism of Maisonneuve fracture is of great clinical significance and can better guide clinical treatment.

[Concentrations, Sources, and Health Risks of PM2.5 Carrier Metals in the Beijing Urban Area and Suburbs].

To explore the differences in pollution characteristics, sources, and health risks of PM2.5 carrier metals in urban and suburban areas in Beijing, daily PM2.5 samples were collected from Haidian and Daxing from June to November 2017 and the concentration of PM2.5 and 13 constituent metals were analyzed. The sources of these 13 metal elements were analyzed by positive matrix factorization (PMF), and the health hazards of a subset of 9 metals were evaluated using health risk assessment. The results showed that the concentrations of PM2.5 and 10 metal concentrations in the urban area including Cr, Co, Mn, and Ni were significantly different from those in suburban areas (P<0.05). The source analysis results show four key sources, although their relative contributions vary slightly between urban and rural areas. In urban areas, the main sources are motor vehicles (51.2%), coal burning (19.1%), dust (19.3%), and fuel oil (10.4%); in the suburbs, sources are motor vehicles (47.9%), coal burning (22.6%), dust (20.2%), and electroplating (9.3%). The results of the health risk assessment showed that all metal HQ values in the suburbs were less than 1, and there was no non-carcinogenic risk. Ni and Pb in urban areas, and Cd, Co, Ni, and Pb in suburban areas, do not present a cancer risk, while the R values of As (2.77×10-5), Cd (2×10-6), Co (1.76×10-6), and Cr(Ⅵ) (7.88×10-6) in urban areas and As (8.34×10-6) and Cr(Ⅵ) (4.94×10-6) in suburban areas present some risk of cancer.

Pathoanatomy and Injury Mechanism of Typical Maisonneuve Fracture.

OBJECTIVE: Maisonneuve fracture is a special type of injury which are rare in clinic. The manifestation of such fractures is variable. The aim of this study is to describe the pathoanatomical features of typical Maisonneuve fracture on the basis of radiographs, computed tomography (CT) scans, magnetic resonance imaging (MRI), and intraoperative exploration findings, and to investigate the injury mechanism of this variety. METHODS: The data of 41 patients with Maisonneuve fracture from April 2014 to September 2019 were retrospectively analyzed. There were 32 males and nine females, the average age was 37.9 years (range, 18 to 61 years), the fractures occurred on the left side in 20 patients and on the right side in 21 patients. The cause of injuries were traffic accident in five patients, sprain injury in 20 patients, and falling injury from height in 16 patients. All patients underwent posteroanterior and lateral X-ray examinations of the ankle and calf. CT scan of the ankle was performed in 38 patients, including three-dimensional reconstruction in 33 patients. MRI examination of the ankle and calf was performed in 28 and five patients, respectively. Forty patients were treated with open reduction and internal fixation. The features of proximal fibular fracture, injuries of the medial and posterior structures of the ankle, injuries of the anterior inferior tibiofibular ligament and the interosseous membrane were recorded and analyzed. RESULTS: Forty-one patients had proximal one-third fractures of the fibula including six patients with fracture involving the fibular neck, 30 with proximal one-third fractures of the fibular shaft, and five with proximal-medial one-third junction fracture of the fibular shaft. Thirty-five patients (35/41, 85.37%) with injury of posterior structures, 34 patients had posterior malleolar fracture (34/41, 82.93%), and one patient had posterior inferior tibiofibular ligament rupture (1/41, 2.44%). There were 20 patients with type I fracture, four patients with type II fracture, and 10 patients with type III fracture according to the Haraguchi classification of posterior malleolus fracture. The fracture of the medial malleolus was in 30 patients (30/41, 73.17%), rupture of the deltoid ligament was in 10 patients (10/41, 24.39%), and medial structures intact were in one patient (1/41, 2.44%). All 41 patients had injury of the anterior inferior tibiofibular ligament. CONCLUSIONS: Maisonneuve fracture is characterized by fractures of the proximal fibula and the complete rupture of the anterior inferior tibiofibular ligament. Pronation-external rotation is the main injury mechanism. The manifestations of typical Maisonneuve fracture including that the fibular fracture located in proximal one-third diaphysis and the fracture line was from anterosuperior to posteroinferior.

[Bacterial Community Composition of Activated Sludge from Coking Wastewater].

Coking wastewater is a kind of highly toxic and refractory organic wastewater, and aerobic activated sludge, which is dominated by bacteria, determines the efficiency of coking wastewater treatment. However, the bacterial community structure of activated sludge from coking wastewater has rarely been reported. 454 sequencing technology was applied to investigate the structure and biodiversity of the bacterial community. The results of thermal cluster analysis and principal component analysis demonstrated the differences in biodiversities of different activated sludge bacterial communities. The bacterial communities were mainly composed of Proteobacteria, Planctomycetes, Acidobacteria, Candidatus Saccharibacteria, Bacteroidetes, Cyanobacteria, Actinobacteria, Chloroflexi, Firmicutes, Thaumarchaeota, Ignavibacteriae, Verrucomicrobia and Unclassified bacteria. Proteobacteria was the dominant phylum and its abundance was 36.00%-76.98%. The primary genera were Thiobacillus, Thauera, Comamonas, Caldimonas, Steroidobacter, Nitrosomonas, Phycisphaera and Gp4. Most of these genera were related with aromatic hydrocarbon degradation, nitrification and denitrification processes. These results provide a theoretical basis for removal mechanism of pollutants in coking wastewater.

[Biodiversity of Thiocyanate-degrading Bacteria in Activated Sludge from Coking Wastewater].

Thiocyanate (SCN-) is one of the main sources of COD in coking wastewater, and SCN- removal efficiency of the aerobic unit impacts the requirement of discharging standard. Microbial population in the activated sludge plays an important role in SCN- removal of coking wastewater treatment. However, the community structure has rarely been reported. Using SCN- as the sole carbon and energy source, the removal of 100 mg·L-1,300 mg·L-1 and 600 mg·L-1 SCN- by activated sludge was studied and 454 sequencing technology was applied to investigate the biodiversity of SCN--degrading bacteria. The results showed that 100-600 mg·L-1 SCN- could be effectively removed by acclimated activated sludge, the higher SCN- concentration, the higher removal efficiency, but the lower bacterial community diversity indices. The bacterial communities in initial and acclimated sludge samples were mainly composed of Proteobacteria, Bacteroidetes, Chlorobi, Planctomycetes, Acidobacteria, Nitrospira, Firmicutes and Unclassified bacteria. Bacteroidetes and Proteobacteria were dominant phyla in the sludge. Thiobacillus was responsible for SCN- biodegradation in coking wastewater, and its abundance in three sludge samples was 3.07%, 8.63% and 0.27%, respectively. When the concentration of SCN- was less than 300 mg·L-1, Thiobacillus was the main degrading bacteria. While at 600 mg·L-1 SCN-, low-abundance degrading bacteria might have synergistic degradation effect. These results have important significance for revealing SCN- removal mechanism in the coking wastewater treatment.

Performance of a haloalkaliphilic bioreactor and bacterial community shifts under different COD/SO4²â» ratios and hydraulic retention times.

Sulfur dioxide from flue gas was converted into sulfate after the absorption of alkaline solutions. Haloalkaliphilic microorganisms have been used in reducing sulfate to decrease expenses and avoid sulfide inhibition. The effects of different COD/SO4(2-) ratios and hydraulic retention times (HRTs) on the sulfate removal efficiency and bacterial community were investigated in model experiments. Ethanol showed better performance as an electron donor than lactate. The optimum COD/SO4(2-) ratio and HRT were 4.0 and 18 h, respectively, with respective sulfate removal efficiency and rate of 97.8 ± 1.11% and 6.26 ± 0.0710 g/Ld. Sulfide concentrations reached 1,603 ± 3.38 mg/L. Based on denaturing gradient gel electrophoresis analysis of 16S rDNA, the major sulfate-reducing bacterium (SRB) was Desulfonatronovibrio sp., which was only detected at a COD/SO4(2-) ratio of 4.0 using ethanol as an electron donor. Different HRTs had no significant effect on the band corresponding to this species. PCR results show that methane-producing archaea (MPA) were from the acetoclastic methanogenic family Methanosarcinaceae. Quantitative real-time PCR did not demonstrate any significant competition between SRB and MPA. The findings of this study indicate that sulfate reduction, nitrate reduction, and sulfide oxidization may occur in the same bioreactor.

Analysis of simultaneous modulated accelerated radiotherapy (SMART) for nasopharyngeal carcinomas.

The purpose of this study was to analyze the clinical outcomes of simultaneous modulated accelerated radiotherapy (SMART) in patients with nasopharyngeal carcinoma (NPC). A total of 97 patients who underwent SMART for NPC between August 2005 and November 2011 were evaluated. The prescribed dose was 69.9 Gy/30 fractions at 2.33 Gy/fraction to the primary gross tumor volume (PGTV) including the nasopharynx gross target volume and the positive neck lymph nodes, and 60 Gy/30 fraction at 2.0 Gy/fraction to the PCTV1; 54 Gy/30 fractions at 1.8 Gy/fraction was given to the PCTV2. Among 59 patients with local advanced disease, 31 patients received concurrent chemoradiotherapy (chemo-RT) with a regimen consisting of 135 mg/m(2) paclitaxel on Day 1 and 25 mg/m(2) cisplatin on Days 1-3. The median follow-up period was 42 months. The local control rate (LCR), distant metastases-free survival (DMFS) and overall survival (OS) rates were 93.3%, 90.3% and 91.6% at 3 years, and 87.6%, 87.9% and 85.7% at 5 years, respectively. There was no significant difference in outcome with respect to these three indicators for Stage III and IV disease treated with/without concurrent chemoradiotherapy (P > 0.05). Acute toxicities included Grade 3 mucositis, skin desquamation, and leucopenia, which occurred in 78 (80.4%), 8 (8.2%), and 45 (46.4%) patients, respectively. No patient had a Grade 3-4 late toxicity. SMART was associated with a favorable outcome for NPC with acceptable toxicity. The local-regional control was excellent but distant metastasis remains the main risk. The combination of SMART and chemotherapy needs to be optimized through further studies to enhance outcomes for locally advanced diseases.

Performance of a haloalkaliphilic bioreactor under different NO3(-)/SO4(2-) ratios.

Effects of NO3(-)/SO4(2-) ratio on denitrification and sulfate removal efficiency were investigated in model experiments applying haloalkaliphilic bioreactor. The reduction of both substrates performed well at different NO3(-)/SO4(2-) ratios ranging from 17.6 to l.5. The removal rates of nitrate and sulfate were 6 and 1.39kgm(-3)d(-1), respectively, at NO3(-)/SO4(2-) ratio 3.0, while sulfide concentration reached up to 703gm(-3). The major sulfate-reducing and denitrifying bacteria were Desulfonatronovibrio sp. and Halomonas campisalis, respectively. Decrease in NO3(-)/SO4(2-) ratio led to obvious changes in bacterial community. Although the sulfate reducers became dominant, the population of denitrifying ones also increased as it was demonstrated by analysis of PCR-amplified 16S rDNA fragments, which suggested that SRB and DB coexisted well in bioreactor.

[Degradation of phenol with a Fe/cu-catalytic heterogeneous-Fenton process].

The catalysts of Fe/AC, Cu/AC and Fe-Cu/AC with active carbon as support were prepared by a wet impregnation method, and were characterized using X-ray diffraction (XRD), nitrogen adsorption and X-ray photoelectron spectroscopy (XPS) measurements; the catalytic heterogeneous-Fenton processes of phenol degradation with these catalysts were also investigated, and the degradation mechanism was discussed with analysis of intermediate products and electron spin resonance (ESR) measurement. The results showed that the active component states varied in different catalysts; CuO was the main state of Cu in Cu/AC and Fe exhibited various valence states in Fe/AC. The degradation rate of phenol with Fe/AC, Cu/AC and Fe-Cu/AC as catalyst in the initial 60 min reached 96.7%, 77.5% and 99%, respectively; the dissolution of a little active-component metal was found in Cu/AC and Fe-Cu/AC, but little Fe in Fe/AC was dissolved; the degradation of phenol was performed by heterogeneous Fe/AC instead of dissolved Fe, and the degradation rate was above 93% after Fe/AC was used for three cycle runs, showing a stable catalytic activity. Under the optimum conditions of pH = 3, T = 303 K, and 4.38 mmol x L(-1) H2O2, the removal of phenol and TOC in the Fe/AC-catalytic Fenton process could reach 97% and 53%, respectively, while little phenol was degraded without catalyst. The ESR results indicated that hydroxyl radical was produced in the catalytic decomposition of H2O2 with Fe/AC as catalyst, demonstrating that the degradation of phenol mainly followed an oxidation pathway of hydroxyl radical; intermediates such as hydroquinone, p-benzenequinone and catechol were obtained, and the results showed thatortho- and para-substitution reaction by hydroxyl might be the main mechanism of phenol oxidation.

[Treatment of anterior cruciate ligament injury with peroneus longus tendon].

OBJECTIVE: To evaluate the effects of anterior cruciate ligament reconstruction with peroneus longus tendon and observe the clinical outcomes of ankle joint after the resection of peroneus longus tendon. METHODS: From January 2006 to December 2009, 35 patients with anterior cruciate ligament injuries were recruited to undergo surgical procedures. There were 30 males and 5 females with an average age of 31.8 years (range: 21 - 56). All anterior cruciate ligament reconstructions underwent arthroscopy. All ligaments were reconstructed with peroneus longus tendon and fixed with absorb screw. The post-operative assessments included the followings:clinical evaluations, Lysholm knee score, KT-3000 arthrometer evaluation and the American Orthopedic Foot and Ankle Society ankle-hindfoot scale AOFAS). RESULTS: All cases were followed up for an average follow-up period of 15 months (range: 12 - 24). The healing time was 6 - 15 weeks.according to the Lysholm knee score, their outcomes were excellent (n = 25), good (n = 6), fair (n = 3) and poor (n = 1). The average score was 97.2 (range: 60 - 100). The rate of excellent and good was 88.6%; according to the KT-3000 arthrometer evaluations, the outcomes were normal (n = 28), nearly normal (n = 4), abnormal (n = 2) and poor (n = 1). Preoperatively, the average anterior displacement was 11.59 ± 1.25 mm and the average anterior displacement at final follow-up 1.76 ± 1.83 mm. The average AOFAS score was 96.3 (range: 84 - 100). Lysholm knee score and KT-3000 arthrometer evaluation had statistical differences (P < 0.05) while AOFAS score showed no difference (P > 0.05). CONCLUSION: Peroneus longus tendon can be a good substitute of anterior cruciate ligament reconstruction. And its resection has no major influence for ankle joint.

[Operative treatment of displaced intra-calcaneal fractures].

OBJECTIVE: To explore the clinical efficacies of displaced intra-calcaneal fractures with operative treatment. METHODS: From January 2005 to December 2010, 103 calcaneal patients (92 males, 11 females) were recruited. The mean age was 45.8 years old (range: 23 - 65). All received operative treatment. They included left calcaneal fractures (n = 51), right calcaneal fractures (n = 40) and bilateral calcaneal fractures (n = 12). All patients were of closed fractures. According to the Sanders classification, there were type II (n = 15), type III (n = 75) and type IV (n = 13). A modified lateral approach with profiled plate fixation was adopted for all. Partial weight-bearing occurred at 6 weeks and full weight-bearing at 12 weeks. Function assessment was made with the American Orthopedic Foot and Ankle Society ankle-hindfoot scale (AOFAS). RESULTS: The mean follow-up period was 18 months (range: 6 - 30) and the mean healing duration 12 weeks (range: 8 - 15). Two cases had incision dehiscence. After the removal of plate, the skin healed. Eight cases were associated with subtalus arthritis and painful walking. Three cases of caved calcaneal surface appeared after weight-bearing. According to the AOFAS foot score, the outcomes were excellent (n = 83), good (n = 13), fair (n = 5) and poor (n = 2). And the excellent and good rate was 93.2%. CONCLUSION: With a modified lateral approach, displaced intra-calcaneal fracture may be treated with a satisfactory clinical efficacy.But an orthopedic surgeon should master skillful surgical techniques.

[Therapeutic efficacies of bone grafing for calcaneal intra-calcaneal fractures].

OBJECTIVE: To evaluate the efficacies of treating intra-calcaneal fractures with bone grafting. METHODS: From January 2005 to October 2011, a total of 182 calcaneal patients underwent operations for closed fractures. There were 159 males and 23 females with an average age of 41.2 years old. The fractures were of the following types: left calcaneal (n = 68), right calcaneal (n = 86) and bilateral (n = 28). According to the Sander's classification, there were type II (n = 27), type III (n = 109) and type IV (n = 46). And they were divided into bone graft (n = 94) and non-bone graft (n = 88) groups. All of them underwent a profiled plate fixation via a lateral approach. No external fixation was necessary and early ankle functional exercises started postoperatively. They handled partial weight-bearing at Week 6 and full weight-bearing at Week 12. Their outcomes were assessed by the American Orthopedic Foot and Ankle Society ankle-hindfoot scale (AOFAS) while classification comparison affected the prognosis (P < 0.05). RESULTS: The follow-ups of 10 patients were lost at Month 3. And 172 cases were followed up for an average period of 14.2 months (range: 9 - 16). The average healing duration was 12 weeks (range: 6 - 15). None of follow-up cases had any complication, such as vascular and nerve injury and osteomyelitis. Twenty-nine cases in the non-bone graft group had articular cave-in after weight bearing. And 21 cases were associated with subtalar arthritis. And in the bone graft group, there was no articular cave-in and only 1 case was associated with subtalar arthritis. The outcomes of bone graft and non-graft groups were as follows: excellent (n = 68), good (n = 20), fair (n = 5) and poor (n = 1) vs. excellent (n = 44), good (n = 26), fair (n = 7) and poor (n = 9). The rate of excellent and good was 87.9%. And the post-operative AOFAS scores had statistical differences between 2 groups (P < 0.05). CONCLUSION: Bone grafting is important for improving the therapeutic efficacies for intra-calcaneal fractures.

[Isolation of phenol-degrading bacteria from coking wastewater and their degradation gene].

Phenol and phenolic compounds are main pollutants in wastewater of coking factories. To identify the bacteria responsible for phenol removal in the activated sludge of a coking factory, we isolated bacteria from the sludge directly or after enrichment. From two samples from the aerobic and anaerobic pools, 28 strains belonging to 28 species of 20 genera were obtained after identification with BOX-PCR and further 16S rDNA sequence analyses. Most of them belonged to beta- and gamma-Proteobacteria, four of which are potential novel species of low 16S rDNA sequence similarity to corresponding type strains. From the m-cresol enrichment community, two strains identified and named as Pseudomonas monteilii GCS-AE-J-1 and Pseudomonas plecoglossicida GCS-AN-J-3 were obtained as the efficient degraders; The former can remove 94.6% m-cresol (791 mg/L) in just 48 h; while the latter metabolized 92.2% m-cresol (763 mg/L). Furthermore, the phenol hydroxylase gene was surveyed by PCR from the phenol-degrading strains,and 4 were positively detected. Summarily, quite diverse bacteria were proved of high capability to degrade phenol and phenolic compounds in this report, which play important role in biotreatment of phenol compounds.

[Selective recovery of copper, zinc and nickel from printed circuit boards by ammonia leaching under pressure].

The ammonia/ammonium leaching process using oxygen as oxidant in autoclave was studied to extract copper, zinc and nickel from printed circuit board. Parameters such as leaching time, concentration of leaching reagents, stirring speed, oxygen pressure and temperature were optimized. The best results were achieved when the leaching was carried out at 55 degrees C for 150 minutes, using 4 mol/L NH4OH and 1 mol/L (NH4)2CO3 as leaching solution, with 700 r/min stirring speed and 0.2 MPa oxygen. With this method, Zn, Cu and Ni could be effectively recovered from printed circuit boards by 100%, more than 99% and more than 64%, respectively. The kinetics of Cu leaching behavior was studied and it was found that the shrinking core model described it well. It was a diffusion control process and the apparent activation energy was 14.68 kJ/mol.

[Advanced treatment of coking wastewater with a novel heterogeneous electro-Fenton technology].

A novel electro-catalytic reactor, with oxygen-reduction cathode (PAQ/GF), dimensionally stable anode (IrO2-RuO2 -TiO2/ Ti) and heterogeneous catalysts, is developed for advanced treatment of coking wastewater after biological process, integrating cathodic and anodic simultaneous oxidation processes. A PAQ/GF electrode was synthesized by the electro-polymerization of 2-ethyl anthraquinone on graphite felt, which was characterized with cyclic voltametry measurements; the results indicated that the PAQ/GF electrode showed high reversibility for oxidation-reduction reaction of anthraquinone and catalytic activity for O2 reduction to H2O2; 13.5 mmol/L H2O2 was obtained after electrolysis for 6 h at -0.7 V (vs. SCE) and pH 6 with a current efficiency of 50% in a membrane reactor. Fe-Cu/Y350 catalysts, prepared by impregnation method, could catalyze the production of hydroxyl radicals (*OH) from H2O2, which was confirmed both by fading reaction of crystal violet and oxidation of *OH-probe compound (p-chlorobenzoic acid); Fe-Cu/Y350 also showed high catalytic-activity for the oxidation of organics by hypochlorous sodium, because COD removal of coking wastewater reached 26% in the catalytic process while only 11% of COD removal was obtained in the absence of Fe-Cu/Y350. COD removal of coking wastewater reached 49.4% (26.0% and 23.4% in cathodic system and anodic system, respectively) in the developed electrolytic-reactor, which was higher than that of conventional cathodic-anodic-oxidation process (29.8%). At optimal reaction condition of initial COD = 192 mg/L, I = 10A x m(-2) and pH 4-5, more than 50% COD were removed after electrolysis for 1 h. The mechanism might be as follows: in cathodic system, H2O2 is generated from reduction of O2 on PAQ/GF cathode, and catalyzed by Fe-Cu/Y350 for production of *OH, which causes mineralization and degradation of organic pollutants; in anodic system, Cl2 and HClO are generated from Cl- oxidation on IrO2-RuO2-TiO2/Ti anode and the organic pollutants are oxidized by Cl2, and HClO with Fe-Cu/Y350 catalysts or by direct anodic oxidation.

[The production of hydroxyl radical in HRP-NADH-H2O/O2 systems and its application in chlorobenzene removal].

The mechanism of radical generation in HRP-NADH-O2/H2O2 systems and state-change of horseradish peroxidase (HRP) was investigated by using ESR and UV measurements, and the novel enzyme-coenzymatic systems were performed to degrade chlorobenzene as a non-phenolic persistent organic pollutants. The UV results showed that compound III was produced from HRP oxidized by hydrogen peroxide with the catalysis of NADH, which would generate hydroxyl radical. The ESR results demonstrated the production of *OH and O2-. in enzyme-coenzymatic system in the presence of O2 or H2O2 with DMPO and POBN as spin-trappers, respectively. In HRP-NADH-H2O2 system, compound III was the main state of HRP in the initial 10 min, and then converted to HRP with generating hydroxyl radical; and after the addition of oxygen, the production of hydroxyl radical was promoted rapidly, as 4 times as that of the system in absence of oxygen. The addition of SOD(Zn-Cu) decreased the production of hydroxyl radical significantly, resulting from that SOD eliminated O2 reduction to O2-. by NADH and then inhibited *OH formation. The results showed that NADH could improve by about 20% enzyme activity of HRP for phenol removal. The removal of chlorobenzene with HRP-NADH-H2O2 and HRP-NADH-H2O2-O2 systems reached 24.6% and 48.2%, respectively, which was much higher than that with traditional enzymatic system (1.42%), showing a promising prospect in proposal

[Marine SRB community reducing sulfate wastewater in flue gas desulfurization].

An SRB community (SRB-2) was enriched from marine sediment for the treatment of sulfate-rich wastewater of high salinity, and the effect of salinity, temperature, pH value, carbon source, concentration of sulfate and the form of Fe on the activity of SRB-2 was studied. The results show that SRB-2 is a halophilous and moderately mesophilous SRB community. The optimal conditions for its growth are as follows: temperature of 30-40 degrees C and pH value of 7.4-8.3; it can endure 5,200 mg/L SO4(2-) and 60g/L NaCl. Zero-valent Fe can promote the reductive activity of SRB-2, while Fe2+ inhibits that. SEM and optical microscopic measurements indicate many rod-shaped and spiral bacteria on the surface of padding in reactor and black sticky substance composed of rod-shaped bacteria on the bottom of reactor. This sticky substance might be cumulus of culture SRB-2-64 (GenBank accession number: EU167911).

[Study on spectrum of solvent extraction of chromium( VI) by primary amine].

The Cr(VI) solvent extraction in near neutral aqueous solution by primary amine was experimentally studied by the inductively couple plasma-atomic emission spectrometry (ICP-AES), laser Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance spectroscopy (1H NMR). The ICP-AES analysis of the aqueous phase before and after solvent extraction showed that primary amine could extract Cr(VI) from nearly neutral solution. Laser Raman spectroscopy of loaded organic phase showed that a new peak appeared at 890 cm(-1) after Cr(VI) was extracted by primary amine. FTIR showed the process that primary amine extracted Cr(VI) from nearly neutral aqueous solutions was different from anion exchange mechanism, and the Cr(VI) extracted into the organic phase resulted in the appearance of the peak at 885 cm(-1) of FTIR which justified that the peak at 890 cm(-1) of Raman was caused by Cr(VI). The 1H NMR spectroscopy showed that the value of chemical shift of protons of -NH2 decreased after extraction, and it is believed that primary amine was associated with Cr(VI) through hydrogen bonding. On the basis of the spectroscopic analysis results above, the mechanism of Cr(VI) extraction by primary amine from nearly neutral aqueous solutions was believed to be solvation with molecular association between primary amine and Cr(VI) through hydrogen bonding.