三维电解强化木醋液废水可生化性

该文主要研究不同有机负荷发酵条件下废水的毒性作用规律,并考察三维电解技术的解毒效果.实验结果表明,随着有机负荷的升高,产甲烷活性抑制程度逐渐增强且COD去除率急剧降低,在4 g COD/L时产甲烷抑制率达到38.2％.结合高通量测序技术对发酵过程中细菌和古菌进行分析,发现微生物菌群结构发酵前后变化较为明显.而经优化的三...     

仲钨酸铵(APT)废水除砷氟探索试验研究

针对研究设计院仲钨酸铵生产产生的废水提出一种合理的处理工艺,使废水经处理后达标排放.研究结果表明:两种处理方法可以达标排放.一是废酸中和-石灰沉淀,二是硫酸中和-石灰沉淀砷和氟均可达到国家废水排放标准;氟离子浓度提高到700 mg/L,该方法也适用.     

Production of electricity from ethanol and ammonium based wastewater via photo-electrochemical process

A PEC cell is tested with two types of electrolyte (e.g., electrolyte pollutant and alcohols) under irradiation with a Xenon lamp through an IR cutoff filter (IRA-25S). The main objective of this study is to optimize the production of electricity from wastewater containing ethanol and ammonium using a photo-electrochemical (PEC) process. DOE statistical analysis was used to optimize the parameters that influenced the process, namely the active area of photoanode and the concentration of electrolyte. The significance level of the active area of a photo-anode was found to be within 0.5–1.0 cm², the electrolyte concentrations were found to be 5–20% by volume and the types of electrolytes used included ammonia and an ethanol aqueous solution. For the optimization process, the response surface method (RSM) using central composite design (CCD) was applied to generate a map of the response. The results were statistically analyzed using an analysis of variance (ANOVA) to identify the factors that influence the production of the current density from a PEC cell. An electrolyte containing ethanol was found to produce higher currents than electrolyte containing ammonium. The optimum parameters that produced the maximum current density of 0.77 mA/cm² were achieved using an ethanol electrolyte with an active area of 0.73 cm² and a concentration of 20% by volume. Confirmation experiment showed that the current density is about 97% similar to the expected value that is 0.75 mA/cm².     

Effect of catalyst on electrolysis of ammonia effluents

The electrolysis of ammonia (NH₃) was studied as a remediation process for the removal of ammonia from wastewater, with the advantage of producing hydrogen while returning clean water to the environment. An electro-catalyst able to support the electro-oxidation of ammonia at low concentrations was designed. Two substrates were tested, Raney nickel and carbon fiber. Carbon fiber was found to be a better substrate for the electrolysis of ammonia at low concentrations. The performance of noble metals such as Rh, Pt and Ir, electroplated on the carbon fiber substrate was also evaluated. Rh–Pt–Ir and Pt–Ir on carbon fiber substrate were found to be the most promising electrodes for the electrolysis of ammonia at low concentrations. The maximum ammonia conversion was 91.49 ± 0.01% for a typical concentration of ammonia found in sewage water and the Faradaic efficiency was 91.81 ± 0.13% on the selected anode.     

二维与三维电极法处理苯酚废水试验研究

以苯酚模拟废水为研究对象,对pH值、电解电压、电解质浓度、电解时间进行L16（44）正交试验,确定电催化氧化法处理苯酚废水的最佳反应条件为：pH值为6,电解电压为9 V,电解质浓度为20 g/L,电解时间为120 min。在此基础上,确定三维电极法最佳活性炭投加量为150 g/L,通过试验得出,在一定时间下,三维电极法废水处理效果明显优于二维电极法。     

电混凝法处理电镀废水中的Cu^2＋和Zn^2＋

利用电混凝法处理含Cu^2＋和Zn^2＋的电镀废水,系统地考察了电解电压、进水pH值、极板间距、电解时间等因素对废水处理效果的影响,确定了最佳的电解条件。实验结果表明,电混凝法处理的电镀废水出水水质较好。当电压为80 V,pH值为5,电解时间30 min,极板间距为10 mm时,处理后的废水中Zn2＋浓度为0.36mg/L,去除率达到97.9%,Cu^2＋浓度为0.0049 mg/L,去除率达到99.9%,均可达到国家规定的排放标准,且该法运行方便,处理时间短,是较理想的电镀废水处理工艺。     

Characteristics and anode reaction of organic wastewater-assisted coal electrolysis for hydrogen production

Electrolytic hydrogen production has the advantages of distributed on-demand hydrogen production, high purity and facile coupling with renewable energy sources, but this process is very energy intensive. In this study, the organic wastewater-assisted coal electrolysis process for hydrogen production was studied in an H-type electrolytic cells. Part of the energy can come from the carbon sources in coal and wastewater to reduce power consumption. Linear sweep voltammetry and potentiostatic techniques were used to study the electrolysis characteristics and anode reaction of the wastewater coal slurry. The results showed that the difference in the composition of the wastewater made the electrolysis characteristics quite different. The gas washing water, sulfur water and slag water produced by coal conversion could significantly increase the current density of coal slurry electrolysis. As for the gas washing water, it has no obvious effect on the catalytic effect of Fe³⁺, and the increase in current density was mainly due to the effects of organic matter and chloride. With increasing voltage, the main anode reaction of the wastewater coal slurry was divided into three stages, namely oxidation of coal particles (0.7–1.0 V), oxidation of organic matter in wastewater (1.0–1.5 V) and oxidation of chloride ions (1.5–2.0 V). Below the chlorine oxidation potential, chloride ions could also promote the oxidation of coal particles. The oxidation mechanism of coal slurry in the presence of wastewater was proposed.     

High levels of ammonia nitrogen for biological biogas upgrading

This study aimed to propose a novel method for ex-situ biogas upgrading by adding ammonium chloride to increase the concentration of ammonia nitrogen. The results showed that ammonia nitrogen had a significant effect on biogas upgrading. The maximum content of CH₄ reached 94.1% when the concentration of ammonia nitrogen was 5500 mg/L. At the same time, CH₄ yield of increased by 57.5%. High throughput sequencing results showed that the relative abundance of hydrogenotrophic methanogens reached 73.1%, while that of acetotrophic methanogens was only 1.3%, which greatly increased the content and yield of CH₄. For the bacterial community, Clostridium was the dominant bacteria and the ammonia nitrogen concentration had little effect on it. These results demonstrate that upgrading biogas by increasing the concentration of ammonia nitrogen is feasible.     

沉淀絮凝—吸附处理放射性废水的模拟实验

针对放射废水中三种典型核素去除开展了沉淀絮凝-吸附的实验研究。根据模拟放射性废水的核素的特点,对比不同沉淀剂、絮凝剂和吸附剂对三种核素的去除效果,并开展了铯离子的吸附动力学和竞争离子的影响实验。结果表明,以碳酸钠为沉淀剂可以去除93.2%的锶离子,以聚合硫酸铁为絮凝剂可去除98%以上的锶离子和钴离子,以自制的焦磷钒酸锆为吸附剂可去除99%的铯离子,并且自制的焦磷钒酸锆吸附剂对铯离子具有快速吸附和高效选择的特点。该沉淀絮凝-吸附工艺对钴、锶、铯三种模拟核素的去除率可接近100%,产生的二次废物少,可为核电站放射性废水处理的设计提供技术参考。     

氮源和无机盐对酵母菌发酵酒精浓度的影响

在ypd培养基条件下,研究了尿素这种氮源对酒精发酵的影响,发现其对酵母菌发酵生成酒精的最佳浓度值为9.6g/L.并对5种发酵无机盐硫酸镁、硫酸锌、氯化镁、氯化铁、磷酸二氢钾的浓度与发酵酒精浓度之间的关系进行研究,初步找到了该株酵母所需无机盐的临界值,分别是硫酸镁为4.8g/L,磷酸二氢钾为4.8g/L,氯化镁为4.8g/L.添加硫酸锌、氯化铁的两组实验得到的乙醇产量明显比其他组要低,此酵母菌发酵随浓度的增大乙醇产量降低,由此推断硫酸锌、氯化铁对此种酵母菌发酵有着制约作用.     

Lipid production in mixotrophic cultivation of Chlorella vulgaris in a mixture of primary and secondary municipal wastewater

Microalgae's biomass productivity and oil content depend heavily on the method of its cultivation. In this study, nutrient removal from municipal wastewater by Chlorella vulgaris in batch culture was investigated. Carbon dioxide was supplied from sodium hydrogen carbonate. Effect of parameters including light intensity, sodium hydrogen carbonate concentration, and daily illumination time on the productivity of biomass and lipid was investigated. Lipid and biomass production of C. vulgaris increased at higher concentration of sodium hydrogen carbonate concentration and higher light intensity until a certain value and then decreased, but longer daily illumination time, increased both biomass and lipid productivity. Cultivation of C. vulgairs in mixotrophic mode was also studied in a mixture of primary and secondary wastewater with different ratios (25, 50 and 75 volume percent of the primary wastewater). It was observed that using 25% of the primary wastewater results in 100% COD removal, 100% ammonium removal and 82% nitrate elimination. Biomass productivity and lipid productivity of C. vulgaris in a mixture of primary (25%) and secondary wastewater were 138.76 mg/L/d and 45.49 mg/L/d, respectively.     

NiO hollow microspheres as efficient bifunctional electrocatalysts for Overall Water-Splitting

Development of efficient, earth-abundant and low-cost electrocatalyst for effective water electrolysis is highly demanding for production of sustainable hydrogen energy. In this paper, we report the cost-effective synthetic protocol for porous NiO hollow spheres in large scale through a simple spray drying strategy, using aqueous nickel ammonium carbonate complex solution, followed by calcination. The synthesized NiO hollow spheres calcined at 300 °C (NiO-300) are porous, made of nanoparticles in size range of 10–16 nm with a size range of 2.5–4 μm and total surface area of 120 m²/g. The NiO-300 exhibited excellent bifunctional electrocatalytic water splitting characteristic, both OER, and HER, in basic solution. NiO-300 modified glassy carbon electrode showed superior water electrolysis kinetics and to achieve 10 mA cm^?2 current density, it required 370 mV overpotential for OER and 424 mV overpotential for HER in 1 M KOH. It is also worked well with cost-effective plastic chip electrode. An assembled two-electrode system by pairing NiO modified plastic chip electrode as both anode and cathode in a 1.0 M KOH electrolyte for overall water splitting exhibit clear bubble formation at 1.6 V potential.     

Enhancement of fermentative biohydrogen production from textile desizing wastewater via coagulation-pretreatment

A real textile desizing wastewater (TDW) was coagulation-pretreated to enhance its potential of biohydrogen production. Batch fermentation showed that the hydrogen production was efficiently enhanced (550 and 120% increments for hydrogen production rate and hydrogen yield, respectively) and the production performance was substrate-concentration dependent. A peak hydrogen production rate of 3.9 L/L-d and hydrogen yield of 1.52 mol/mol hexose were obtained while using coagulant GGEFloc-653 at a dosage of 1 g/L to pretreat TDW with the concentration of 15 g total sugar/L. The coagulation-pretreatment could have butyrate-type fermentation with high biohydrogen production and the removed some toxic materials that might drive the metabolic pathways to those not favoring biohydrogen production. Based on the data obtained, strategies to operate the coagulation and biohydogen fermentation are suggested. Moreover, fermentation effluent utilization such as for two-stage biogas production and further biohythane (a mixture of H₂ and CH₄) generation are also elucidated.     

Biofilm Control With New Microparticles With Immobilized Biocide

Biofouling of heat exchangers, pipes, and valves isan unavoidable hazard in industrial plants. Operators have to face the problems of cleaning the fouled equipment, treating the wastewater from the discharge of antimicrobial cleaning agents (biocides, surfactants, etc.), and protecting the consumer from contamination risks. To tackle these problems, a targeted cleaning technique is here proposed that unites efficient removal of the biological deposits (specifically targeting the places where deposits grow) with low consumption of cleaning agents. The goal is to develop microparticles with functionalized surfaces that act as carriers of biocidal molecules, attach to biofilm surfaces, and deliver the biocide on the desired sites. This novel biofilm control technology may provide cost-effective, environmental- and health-friendly strategies that will improve operational efficacy. Previously, our group had performed studies with polystyrene (PS) microparticles functionalized with the biocide benzyldimethyldodecylammonium chloride (BDMDAC) against biofilms of Pseudomonas fluorescens. BDMDAC-functionalized microparticles were prepared using the layer-by-layer self-assembly (LBL) technique. Since PS particles are very expensive, our group tested calcium carbonate microparticles (CaCO₃) (diameter: 3 μm), produced by the same LBL assembly technique. These microparticles have the advantage of being cheaper, porous, and highly abundant in nature. In this study, P. fluorescens biofilms were exposed to 6.33 mg/L and 11.75 mg/L of BDMDAC-coated CaCO₃ microparticles for 60 min. This strategy promoted inactivation of 81.9% (6.33 mg/L) and 93.3 % (11.75 mg/L mg/L) of the total population. As a control, free BDMDAC was tested against P. fluorescens biofilms, demonstrating similar inactivation (p > 0.05) under the new strategy.     

Effect of cell immobilization,hematite nanoparticles and formation of hydrogen-producing granules on biohydrogen production from sucrose wastewater

This study investigated the effect of granules formation, hematite nanoparticles and biofilm carriers on biohydrogen production from sucrose wastewater in continuous stirring tank reactors operated at 12 h HRT, pH of 5.5 and 35 °C. Granular-based bioreactor was subjected to acid incubation period for 24 h by shifting the pH from 5.5 to 3. Before application of the acid incubation, hydrogen-producing granules (HPGs) diameter and hydrogen production rate (HPR) of 0.5 mm and 4.3 L/L.d, respectively were measured at 10 g-sucrose/L. Application of acid incubation enhanced the granulation process, where the particle size increased to 2.8 mm and higher HPR of 7.8 L/L.d was obtained. Higher sucrose concentration (15–30 g?L) enhanced HPGs diameter and increased the HPR. At 10 g-sucrose/L, addition of hematite nanoparticles increased the HPR to 5.9 L/L.d higher than 3.87 L/L.d measured in control reactor. Biofilm-based reactor showed HPR of 2.48 L/L.d lower than the control reactor.     

Recovery of metal values from spent nickel–metal hydride rechargeable batteries

A hydrometallurgical process is developed for the separation and recovery of metal values such as nickel, cobalt and rare earths from spent nickel–metal hydride (Ni–MH) rechargeable batteries. After removal of the external case, the electrode materials are dissolved in 2 M sulfuric acid solution at 95°C. The resulting liquor contains typically (g l⁻¹), 10.6 Ni, 0.85 Co, 1.70 Fe, 0.36 Zn, 0.21 Al, 0.54 Mn, 1.73 La, 0.10 Ce, 0.33 Pr, 1.10 Nd and 0.032 Sm. The pH is around 0.4. The rare earth values are recovered from the liquor by means of a solvent extraction circuit with 25% bis(2-ethylhexyl) phosphoric acid (D2EHPA) in kerosene, followed by precipitation with oxalic acid. A mixed rare earth oxide of about 99.8% purity is obtained after calcination of the precipitate. The total yield of rare earths approaches 93.6%. The cobalt and nickel in the raffinate are effectively separated by solvent extraction with 20% bis(2,4,4-tri-methylpenthyl) phosphinic acid (Cyanex 272) in kerosene. The individual cobalt and nickel are then recovered as oxalates by the addition of oxalic acid. Cobalt and nickel oxalates with purities close to 99.6% and 99.8%, respectively, are obtained. The overall recoveries are over 96% for both cobalt and nickel. A total flowsheet of the process for recovery of rare earths, cobalt and nickel from spent Ni–MH batteries is proposed.     

皇竹草厌氧发酵特性及稀土元素溶出研究

为探讨稀土尾矿区修复用皇竹草的厌氧发酵特性和发酵过程稀土元素溶出情况,开展不同发酵浓度（总固体浓度分别为2%、4%、6%、8%、10%）的中温（37±1℃）批式厌氧发酵实验。结果表明,总固体（TS）浓度为4%条件下皇竹草产甲烷性能最佳,日产甲烷率和累积产甲烷率分别为25.56mL/g和197.33m L/g。采用修正Gompertz方程能较好地模拟不同TS下皇竹草发酵累积产甲烷率的变化。分析发酵液中稀土元素浓度变化,结果表明,皇竹草内的稀土元素在厌氧发酵过程中只发生小部分溶出,主要包括La、Ce、Nd、Sc、Y等,各处理发酵液中稀土元素浓度并未超出文献报道的抑制浓度。相关性分析结果表明,稀土元素溶出率与发酵体系的TS浓度、化学需氧量（COD）呈负相关,与pH呈正相关。研究可为稀土矿区皇竹草沼气工程应用和发酵剩余物的肥料化利用提供指导。     

Exergy analyses of green hydrogen production methods from biogas-based electricity and sewage sludge

In this study, five models are considered for the use of biogas-based electricity and sewage sludge obtained from a municipal wastewater treatment plant for green hydrogen production. These models include alkaline, PEM, high temperature water electrolysis, alkaline hydrogen sulfide electrolysis and dark fermentation biohydrogen production processes. Energy and exergy analyses are performed on these models by applying thermodynamic procedures and the results are compared. The daily hydrogen production rates of the models are found as 594, 625.4, 868.6, 10.8 and 56.74 kg and the exergetic efficiencies of the models are calculated as 19.81, 20.66, 25.83, 24.86 and 60.54%, respectively. In terms of the exergetic efficiency, the dark fermentation biohydrogen production process is found to be superior to the other models, followed by the high temperature steam electrolysis process. This paper aims to determine the most appropriate model for a wastewater treatment plant among the considered models in terms of exergy efficiency.     

Generation of hydrogen from magnesium hydride oxidation in water in presence of halides

We have performed a systematic analysis of magnesium hydride oxidation by water in presence of several transition, non-transition metals and ammonia halides. It was observed that the most effective catalysts of the process are ammonia chloride and bromide, magnesium chloride and a few mixed salts: magnesium chloride mixed with aqueous solutions of ammonium, copper or potassium chlorides. It was observed that solution amount impacts the reaction rate, but not the overall hydrogen yield. The fastest MgH₂ oxidation (120 min to completion; ~100% hydrogen yield) was observed when it was activated by the mixture of MgCl₂ and NH₄Cl).     

Effect of ammonia concentration on hythane (H2 and CH4) production in two-phase anaerobic digestion

Co-production of hydrogen and methane by two-phase anaerobic digestion (AD) may offer a sustainable solution for the centralized treatment of food waste (FW), while ammonia accumulation is potentially encountered. A mesophilic two-phase AD was investigated for hydrogen and methane production from FW at varying ammonia concentrations. The process achieved a hydrogen yield of 47.7 mL/g VS and a methane yield of 335 mL/g VS by optimizing the organic loading rate (OLR) and recirculation ratio. Total ammonia nitrogen (TAN) concentration of 4044 mg/L corresponded to a threshold in the hydrogen reactor, above which ammonia would initiate inhibition of hydrogenogenesis and acidogenesis. Methane yield was recovered in the methane reactor after acute inhibiting effects of TAN below 5800 mg/L, while TAN above 6200 mg/L caused chronic inhibition of methanogens. Adjusting hydraulic retention time (HRT) and recirculation ratio in hydrogen and methane reactors reduced TAN to 960 and 2105 mg/L respectively, resulting in successful recovery was achieved in the hydrogen reactor but not in the methane reactor. The two-phase AD for methane and hydrogen production can be a promising solution for ammonia accumulation in AD from FW.