An original ultrasound (US) directly intensified photocatalytic reactor was designed to degrade azo dye pollutant methyl orange (MeO) using Degussa TiO2 as the photocatalyst. The sonolytic, ...photocatalytic and sonophotocatalytic degradation of MeO in the new reactor and the synergistic effect between sonolysis and photocatalysis were investigated. Effects of operation parameters i.e., US power, TiO2 dosage, liquid circulation velocity and air flow rate on degradation efficiency were investigated and optimized. The results showed that all parameters have optimal values for the sonophotocatalytic degradation of MeO, and the optimum conditions for the new process are US power 600W, TiO2 dosage 3g/L, liquid circulation velocity 4.05×10−2m/s and air flow rate 0.2L/min. Under the optimum conditions, 91.52% MeO had been degraded within 1h, and the combination of sonolysis and TiO2 photocatalysis exhibited an obvious synergetic effect.
Micropollutants (MPs) are widely occurring in surface water all over the world with extremely low concentrations, and their treatment requires high energy consumption and efficiency. In this study, a ...large-sized planar photocatalytic reactive ceramic membrane (PRCM) was prepared using the facile dip-coating method with nitrogen-doped TiO2 (N-TiO2-CM) for the purification of tetracycline hydrochloride (TC) as a model MP. The N-TiO2 nanoparticles and the as-prepared N-TiO2-CM were characterized by SEM/EDS, TEM, XPS, UV–Vis DRS, and FT-IR. A fixed bed reactor integrated N-TiO2-CM, and visible LED light was fabricated for the new PRCM water treatment system for the removal of TC with a comprehensive consideration of the degradation rate and permeate flux. The SEM/EDS results indicated that the N-TiO2 was uniformly and tightly loaded onto the flat CM, and the pure water flux could reach over 2000 L/(m2 × h) under a trans-membrane pressure (TMP) of −92 kPa. The fixed bed PRCM water treatment system is extremely suited for MP purification, and the removal efficiency of TC was as high as 92% with 270 min even though its initial concentration was as low as 20 mg/L. The degradation rate and permeate flux of N-TiO2-CM was 2.57 and 2.30 times as high as that of the CM, indicating its good self-cleaning characteristics. The quenching experiments illustrated that the reactive radicals involved in the PRCM process, •OH and •O2−, were responsible for TC degradation. This research also provides a utilization proposal for a scale-up N-TiO2-CM system for water and wastewater treatment.
Reverse osmosis (RO) concentrate produced in the municipal solid waste (MSW) leachate treatment process is extremely hard to be treated because of its high color, high salt content, and high ...concentration of recalcitrant organic compounds. A new multichannel flow reactor with electrode gaps of 5 mm was designed to desalinate and remove organics simultaneously from the RO leachate concentrate (ROLC) by electrochemical oxidation process using the RuO2/IrO2-coated titanium plate (RuO2/IrO2-Ti) as the anodes. The effects of the process parameters of current density (I A), superficial circulating velocity (U L), etc. on the removal efficiency (RE) of the chemical oxygen demand (COD) and average energy consumption ( EC ̅ ) were investigated. The results illustrated that after 3 h of treatment, the RE of COD, Cl–, and color could reach as high as 96.5, 96.7, and 99.6%, respectively. Besides, the EC ̅ of the electrochemical oxidation treatment process is as low as 40.98 kWh/(kg COD), and a new mechanism of the simultaneous removal of COD and desalination has been proposed. This work provides an alternative technology for the treatment of MSW leachate RO concentrate.
Electrochemical oxidation
(EO) is often used in the advanced treatment
of refractory wastewater. However, in a conventional EO process of
direct-current (DC) power supply, oxide layers often form on ...the anodes,
which not only hinder the oxidation reaction on them but also cause
higher energy consumption. In this paper, a biologically treated leachate
(BTL) of municipal solid waste (MSW) was comparably treated by EO
with DC (DC–EO), monopulse (MP–EO), and double pulse
(DP–EO) power source models in a home-made multi-channel flow
reactor. The effects of process parameters of current density (
I
A
), superficial liquid velocity (
U
L
), pulse frequency (
f
P
),
duty ratio (
R
D
), and so forth on the removal
efficiency of chemical oxygen demand (COD) (RE
COD
), total
organic carbon (TOC) (RE
TOC
), and total nitrogen (TN) (RE
TN
) were investigated simultaneously. Average energy consumption
(
) and organic composition of the treated
effluent of DC–EO and MP–EO were also compared comprehensively,
and a new mechanism of MP–EO has been proposed accordingly.
Under optimal conditions, 2 L of BTL was treated by MP–EO for
180 min, and the RE
COD
, RE
TOC
, and RE
TN
could reach as high as 80, 30, and 80%, respectively. Compared with
DC–EO, the
of MP–EO is reduced by 69.27%. Besides,
the kinds of organic matter in the treated effluent of MP–EO
are reduced from 53 in the BTL to 11, which is much less than in the
DC–EO process of 29 kinds. Therefore, the MP–EO process
exhibits excellent removal performance of organics and TN and economic
prospects in the treatment of refractory organic wastewater.
The Merox process was widely applied in the fine chemical industry to convert mercaptans into disulfides by oxidation with oxygen, including dimethyl disulfide (DMDS). In this paper, a new activated ...carbon (AC)-supported sulfonated cobalt phthalocyanine (AC-CoPcS) catalyst was prepared through the chemical linkage of ethylenediamine between them. UV−VIS, FT-IR, BET, and XPS were used to characterize the structure of the new catalyst. Then AC-CoPcS was applied to catalyze sodium methylmercaptide (SMM) oxidation for the preparation of DMDS. The effect of process parameters, such as reaction time, catalyst dosage, reaction temperature, and oxygen pressure on SMM conversion per pass (CPPSMM), yield (YieldDMDS), and purity of the DMDS (PurityDMDS) product were investigated to evaluate the catalytic performance of AC-CoPcS. The new supported catalyst exhibits better catalytic performance than the commercial one and can be properly reused four times to obtain CPPSMM and YieldDMDS higher than 90% and 70%. Under the optimum experimental conditions, the CPPSMM and YieldDMDS could reach as high as 98.7% and 86.8%, respectively, and the purity of the DMDS product is as high as 99.8%. This new supported catalyst exhibits good industrial application prospects.
Antibody was covalently immobilized by amine coupling method to gold surfaces modified with a self-assembled monolayer of thioctic acid. The electrochemical measurements of cyclic voltammetry and ...impedance spectroscopy showed that the hexacyanoferrate redox reactions on the gold surface were blocked due to the procedures of self-assembly of thioctic acid and antibody immobilization. The binding of a specific antigen to antibody recognition layer could be detected by measurements of the impedance change. A new amplification strategy was introduced for improving the sensitivity of impedance measurements using biotin labeled protein–streptavidin network complex. This amplification strategy is based on the construction of a molecular complex between streptavidin and biotin labeled protein. This complex can be formed in a cross-linking network of molecules so that the amplification of response signal will be realized due to the big molecular size of complex. The results show that this amplification strategy causes dramatic improvement of the detection sensitivity of hIgG and has good correlation for detection of hIgG in the range of 2–10 μg/ml.
A new gas-liquid-solid circulating fluidized bed photocatalytic reactor （GLSCFBPR） with internally placed multi-layered UV lamps was developed. Micrometer Gd-TiO2 particles and commercial nanometer ...P25-TiO2 were chosen as the photocatalysts, and the hazardous substance bisphenol A （BPA） was chosen as the model pollutant to investigate the performance of this new photocatalytic system. The results showed that the photocatalytic degradation efficiency of the micrometer Gd-TiO2 particles was similar to that of the nanometer P-25 particles at their respective optimum dosage but the former could be easily separated out by gravity. After investigating the effects of process parameters on the photocatalytic BPA degradation, the response surface method （RSM） was further used for process optimization. The interactions among process parameters, i.e., TiO2 concentration, superficial gas velocity and superficial liquid velocity were discovered and a related analysis was carried out to explore the underlying mechanism. A quadratic mathematic model was established and performed satisfactorily when used for prediction. The optimum conditions for this new process were as follows： TiO2 concentration 4.5 g/L, superficial gas velocity 7.83 x 10-3 m/sec and superficial liquid velocity 8.65 x 10-3 m/sec.
Liposomes are intensively being developed for biomedical applications including drug and gene delivery. However, targeted liposomal delivery in cancer treatment is a very complicated multistep ...process. Unfavorable liposome biodistribution upon intravenous administration and membrane destabilization in blood circulation could result in only a very small fraction of cargo reaching the tumors. It would therefore be desirable to develop new quantitative strategies to track liposomal delivery systems to improve the therapeutic index and decrease systemic toxicity. Here, we developed a simple and nonradiative method to quantify the tumor uptake of targeted and nontargeted control liposomes as well as their encapsulated contents simultaneously. Specifically, four different chelated lanthanide metals were encapsulated or surface-conjugated onto tumor-targeted and nontargeted liposomes, respectively. The two liposome formulations were then injected into tumor-bearing mice simultaneously, and their tumor delivery was determined quantitatively via inductively coupled plasma mass spectroscopy (ICPMS), allowing for direct comparisons. Tumor uptake of the liposomes themselves and their encapsulated contents was consistent with targeted and nontargeted liposome formulations that were injected individually.
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