Kinetics of 2,4-dichlorophenol dechlorination by Pd-Fe bimetallic nanoparticles in the presence of humic acid

The remediation of groundwater which contains chlorinated organic compounds (COCs) by nanoscale bimetallic catalysts has received increasing interest in recent years. This report presents the dechlorination of 2,4-dichlorophenol (2,4-DCP) by Pd-Fe bimetallic nanoparticles in the presence of humic acid (HA) to investigate the feasibility of using Pd-Fe for the in situ remediation of contaminated groundwater. Our experimental results indicated that HA had an adverse effect on the dechlorination of 2,4-DCP by Pd-Fe nanoparticles. The rate constant k values of 2,4-DCP dechlorination were 0.017, 0.013, 0.009, 0.006 and 0.004 min?1 for HA concentrations of 0, 5, 10, 15 and 20 mg/L, respectively. The relationship between HA dosage and k values can be described as a linear model.

Analysis of cancer-specific survival in patients with metastatic colorectal cancer: A evidence-based medicine study

BACKGROUND Metastatic colorectal cancer(mCRC)is a common malignancy whose treatment has been a clinical challenge.Cancer-specific survival(CSS)plays a crucial role in assessing patient prognosis and treatment outcomes.However,there is still li-mited research on the factors affecting CSS in mCRC patients and their corre-lation.AIM To predict CSS,we developed a new nomogram model and risk grading system to classify risk levels in patients with mCRC.METHODS Data were extracted from the United States Surveillance,Epidemiology,and End Results database from 2018 to 2023.All eligible patients were randomly divided into a training cohort and a validation cohort.The Cox proportional hazards model was used to investigate the independent risk factors for CSS.A new nomogram model was developed to predict CSS and was evaluated through internal and external validation.RESULTS A multivariate Cox proportional risk model was used to identify independent risk factors for CSS.Then,new CSS columns were developed based on these factors.The consistency index(C-index)of the histogram was 0.718(95%CI:0.712-0.725),and that of the validation cohort was 0.722(95%CI:0.711-0.732),indicating good discrimination ability and better performance than tumor-node-metastasis staging(C-index:0.712-0.732).For the training set,0.533,95%CI:0.525-0.540;for the verification set,0.524,95%CI:0.513-0.535.The calibration map and clinical decision curve showed good agreement and good potential clinical validity.The risk grading system divided all patients into three groups,and the Kaplan-Meier curve showed good stratification and differentiation of CSS between different groups.The median CSS times in the low-risk,medium-risk,and high-risk groups were 36 months(95%CI:34.987-37.013),18 months(95%CI:17.273-18.727),and 5 months(95%CI:4.503-5.497),respectively.CONCLUSION Our study developed a new nomogram model to predict CSS in patients with synchronous mCRC.In addition,the risk-grading system helps to accurately assess patient prognosis and guide treatment.

Visible-light-initiated malic acid-promoted cascade coupling/cyclization of aromatic amines and KSCN to 2-aminobenzothiazoles without photocatalyst

By using ambient air as the oxidant and malic acid as the promoter,a practical method for the preparation of 2-aminobenzothiazoles through visible-light-initiated cascade reaction of aromatic amines and KSCN in eco-friendly bis(methoxypropy)ether under metal-,hazardous additive-,photocatalyst-free conditions was established.

Dechlorination mechanism of 2,4-dichlorophenol by Ni/Fe nanoparticles in the presence of humic acid

To understand the feasibility of its application to the in situ remediation of contaminated groundwater,the dechlori-nation of 2,4-dichlorophenol (2,4-DCP) by Ni/Fe nanoparticles in the presence of humic acid (HA) was investigated.We found that,as high performance liquid chromatography (HPLC) was used,the 2,4-DCP was first quickly reduced to o-chlorophenol (o-CP) and p-chlorophenol (p-CP),and then reduced to phenol as the final product.Our experimental results indicated that HA had an adverse effect on the dechlorination of 2,4-DCP by Ni/Fe nanoparticles,as the HA concentration increased,the removal rate decreased evidently.It also demonstrated that 2,4-DCP was reduced more easily to o-CP than to p-CP,and that the sequence of the tendency in dechlorination of intermediates was p-CP>o-CP.Transmission electron microscope (TEM) showed that HA could act as an adsorbate to compete reactive sites on the surface of Ni/Fe nanoparticles to decrease the dechlorination rate.Also we con-cluded that the dechlorination reaction of 2,4-DCP over Ni/Fe nanoparticles progressed through catalytic reductive dechlorination.

Manganese removal from the Qiantang River source water by pre-oxidation:A case study

We evaluated several different pre-oxidation treatments, namely the introduction of either potassium permanganate (KMnO4), chlorine (Cl2), or both to remove manganese (Mn) from the Qiantang River source water. Our results showed that Mn removal percentages were 12.7%, 71.0%, 17.4% and 58.7% when none of the oxidants, KMnO4 only, Cl2 only, or both oxidants were added, respectively. Furthermore, a field study showed that when the available Mn concentration in the source water was 0.14 mg/L, it could be reduced to less than 0.05 mg/L when a solution of KMnO4 (0.47 mg/L) was added as the oxidant.

A simple and convenient method for the synthesis of S-aryl phosphorothioates catalyzed by cesium hydroxide

In the presence of a catalytic amount of cesium hydroxide, the corresponding S-aryl phosphorothioates can he obtained by the reactions of dialkyl phosphites with diaryldisulfides in excellent yields at room temperature, using DMSO as a solvent. The reaction mechanism was discussed. The method provides a new and expedient path for the preparation of $-aryl phosphorothioates.