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As the rapidly growing number of waste lithium-ion batteries (LIBs), the recycling and reutilization of anode graphite is of increasing interest. Converting waste anode graphite into functional materials may be a sensible option. Herein, a series of carbonaceous catalysts (TG) were successfully prepared using spent anode graphite calcined at various temperatures and applied for activating peroxymonosulfate (PMS) to degrade atrazine (ATZ). The catalyst obtained at 800 °C (TG-800) showed the optimum performance for ATZ removal (99.2% in 6 min). Various experimental conditions were explored to achieve the optimum efficiency of the system. In the TG-800/PMS system, free radicals (e.g., SO 4 ·- , HO·), singlet oxygen ( 1 O 2 ), together with a direct electron transfer pathway all participated in ATZ degradation, and the ketonic (CO) group was proved as the leading catalytic site for PMS activation. The potential degradation routes of ATZ have also been presented. According to the toxicity assessment experiments, the toxicity of the intermediate products decreased. The reusability and universal applicability of the TG-800 were also confirmed. This research not only provides an efficient PMS activator for pollutant degradation, but also offers a meaningful reference for the recovery of waste anode graphite to develop environmentally functional materials., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Rural waste accumulation leads to heavy metal soil pollution, impacting microbial communities. However, knowledge gaps exist regarding the distribution and occurrence patterns of bacterial communities in multi-metal contaminated soil profiles. In this study, high-throughput 16 S rRNA gene sequencing technology was used to explore the response of soil bacterial communities to various heavy metal pollution in rural simple waste dumps in karst areas of Southwest China. The study selected three habitats in the center, edge, and uncontaminated areas of the waste dump to evaluate the main factors driving the change in bacterial community composition. Pollution indices reveal severe contamination across all elements, except for moderately polluted lead (Pb); contamination severity ranks as follows: Mn > Cd > Zn > Cr > Sb > V > Cu > As > Pb. Proteobacteria, Actinobacteria, Chloroflexi, and Acidobacteriota predominate, collectively constituting over 60% of the relative abundance. Analysis of Chao and Shannon indices demonstrated that the waste dump center boasted the greatest bacterial richness and diversity. Correlation data indicated a predominant synergistic interaction among the landfill's bacterial community, with a higher number of positive associations (76.4%) compared to negative ones (26.3%). Network complexity was minimal at the dump's edge. RDA analysis showed that Pb(explained:46%) and Mn(explained:21%) were the key factors causing the difference in bacterial community composition in the edge area of the waste dump, and AK(explained:42.1%) and Cd(explained:35.2%) were the key factors in the center of the waste dump. This study provides important information for understanding the distribution patterns, co-occurrence networks, and environmental response mechanisms of bacterial communities in landfill soils under heavy metal stress, which helps guide the formulation of rural waste treatment and soil remediation strategies., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Iron complex regulated electrochemical reaction was triggered for revealing the reaction mechanism, degradation pathway, and applied potential of perfluorooctanoic acid (PFOA). The increased PMS concentrations, electrode spacing, and current density significantly enhanced PFOA elimination, with current density exhibiting a relatively strong interdependency to PFOA complete mineralization. The synergy between PMS and electrochemical reactions greatly accelerated PFOA decomposition by promoting the generation of key reaction sites, such as those for PMS activation and electrochemical processes, under various conditions. Furthermore, density functional theory calculations confirmed that the reciprocal transformation of Fe 2+ and Fe 3+ complexes was feasible under the electrochemical effect, further promoting the generation of active sites. The developed electrochemical oxidation with PMS reaction (EO/PMS) system can rapidly decompose and mineralize PFOA while maintaining strong tolerance to changing water matrices and organic and inorganic ions. Overall, it holds promise for use in treating and purifying wastewater containing PFOA., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The physicochemical properties, chemical fractions of six metals (Cu, Zn, Pb, Cd, Cr, and Mn), and microbial communities of soil around a typical sanitary landfill were analyzed. The results indicate that soils around the landfill were from neutral to weak alkalinity. The contents of organic matter (OM), total nitrogen (TN), total phosphorous (TP), and activities of catalase, cellulase, and urease were significantly higher in landfill soils than those in background soils. Negative correlations were found between pH and metals. Cr was the dominant metal. Cu, Pb, Cr, and Mn were accumulated in the nearby farmland soils. Cd had the highest percentage of exchangeable fraction (33.7%-51.8%) in landfill and farmland soils, suggesting a high bioavailability to the soil environment affected by the landfill. Pb, Cr, and Mn existed mostly in oxidable fraction, and Cu and Zn were dominant in residual fraction. There was a low risk of soil metals around the landfill based on the RI values, while according to RAC classification, Cd had high to very high environmental risk. The MisSeq sequencing results showed that Actinobacteria, Proteobacteria, Chloroflexi, and Acidobacteria were the dominant phyla of bacteria, and the most abundant phylum of fungi was Ascomycota. The NMDS analysis revealed that the landfill could influence soil fungal communities more intensely than bacterial communities. TN, cellulase, and bioavailable metals (Pb-Bio and Cr-Bio) were identified to have main influences on microbial communities. Pb-Bio was the most dominant driving factor for bacterial community structures. For fungi, Pb-Bio was significantly negatively related to Olpidiomycota and Cr-Bio had a significantly negative correlation with Ascomycota. It manifests that bioavailable metals play important roles in assessing environmental risks and microbial community structures of soil around landfill., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Nonferrous metal tailings have long posed a significant threat to the surrounding environment and population. Previous studies have primarily focused on heavy metal pollution in the vicinity of sulfide tailings, while little attention was given to metal mobility and bioavailability within skarn-type tailings profile during weathering. Therefore, this study aimed to investigate the fractionation, bioaccessibility, and ecological risk associated with metallic elements (MEs, including Pb, Cd, Cr, Zn, and Cu) in two representative weathering copper-tailings profiles of Tongling mine (China). This was achieved through the use of mineralogical analyses, BCR extractions (F1: exchangeable, F2: reducible, F3: oxidizable, F4: residual fraction), in-vitro gastrointestinal simulation test (PBET) and risk assessment models. The mineral compositions of two weathering profiles were similar, with quartz and calcite being the dominant minerals, along with minor amounts of siderite, hematite and spangolite. The mean concentration in the tailings profile was approximately 0.31 (Cr), 1.8 (Pb), 12 (Zn), 33 (Cd) or 34 (Cu) times of the local background values (LBVs). The mean content of the bottom weakly-weathering layer in profile was about 0.36 (Cr), 0.91 (Pb), 1.91 (Cd), 2.73 (Zn) or 2.68 (Cu) times of the surface oxide layer, indicating a strong weathering-leaching effect. The average proportion of BCR-F1 fraction for Cd (30.94 %) was the highest among the five MEs, possibly due to its association with calcite. The PBET-extracted fractions for Cd, Zn and Cu were significantly positively correlated with the F1, F2 and F3 fractions of BCR, suggesting that these elements have higher bioavailability/bioaccessibility. The assessment results indicated that Cd posed a higher health risk, while the risk of Cu, Zn, and Pb is relatively low and Cr is safe. In conclusion, this study provides valuable insights into the environmental geochemical behavior and potential risks of MEs in skarn-type non-ferrous metal tailings ponds., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The sesame straw-derived biochar was successfully prepared via alkaline hydrogen peroxide (AHP) pretreatment in this study. Systematic experimental characterizations, 15 relevant batch and column adsorption models, combined with density functional theory (DFT) calculation were used to investigate the performances and micro-mechanisms of Cd 2+ adsorption onto biochar. We found AHP-pretreatment could greatly improve the adsorption performance of biochar for Cd 2+ . The maximum Cd 2+ adsorption capacity of AHP-pretreated biochar (87.13 mg g -1 ) was much larger than that of unpretreated biochar. Cd 2+ adsorption was mainly dominated by the chemisorption of the homogeneous surface monolayer. The hydroxyl and carboxyl groups on the surface of biochar provided preferential adsorption sites, and liquid film diffusion and intra-particle diffusion were two dominant rate-controlling steps. Our results showed that ion exchange, co-precipitation, surface complexation, and Cd 2+ -π interaction were the dominant adsorption mechanisms. Especially, DFT calculations well-identified that lone-pair electrons during complexation and π electrons during coordination were provided by oxygen-containing functional groups and aromatic rings, respectively. The experimental breakthrough curves fitted better with the theoretical value of the BJP model, compared to Thomas, Yoon-Nelson, and EXY models. Overall, our study provides a promising method for Cd 2+ removal from wastewater and resource utilization of agricultural wastes., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Although polydopamine (PDA)-related modification is widely studied in the fabrication of superhydrophobic sponges, the high cost of dopamine limits its widespread application. To imitate PDA modification, a low-cost and facile one-step poly(phenol-amine) modification was performed on melamine sponges in this study. Low-cost catechol and diethylenetriamine (DETA) were used as the monomers, and n-dodecanethiol was used as an additive in the one-step modification. The results confirmed that the poly(phenol-amine) aggregations were successfully anchored on the sponge skeleton surface and that the aggregations were formed via the Schiff base reaction and the Michael addition reaction. Furthermore, the as-prepared sponges still showed excellent mechanical properties after modification. Additionally, the optimally modified sponge (MS-0.5) exhibited superhydrophobic properties with a contact angle value above 150° under various environments, high oil-absorption capacity for various oils and organic solvents, high continuous oil-water separation performance with efficiency greater than 98.8% in 30 cycles, outstanding demulsification performance with 99.52% toward oil-in-water emulsion, and excellent recoverability and long-term stability. Thus, this work provides a feasible facile one-step modification method that can be used in place of PDA-related modification., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Cadmium-contaminated wastewater has attracted increasing concerns due to its non-biodegradable properties and high toxicity. To explore eco-friendly and economically feasible strategies, the screened Alcaligenes faecalis K2 were employed for the biomineralization and recovery of Cd 2+ from wastewater while producing considerable secretory organo-biominerals (SOBs) as bioadsorbents. At 75 mg/L Cd 2+ exposure, 85.5% of Cd 2+ was removed by K2, 43.0% of which was fixed in the granular SOBs. SOBs were convenient for separating from the solution. The adsorption capacity of granular sorbent made from SOBs was verified to be greater than 77.1 mg/g. Practically, 89.5% of 75 mg/L of Cd 2+ could be stably removed while ereK2 continuously generated SOBs in a moving-bed biofilm reactor (MBBR). To sum up, the production of bioadsorbents can be achieved by K2, while removing Cd with live microorganisms, which was conducive to making full use of materials and improving Cd removal efficiency., (Copyright © 2021 Elsevier Inc. All rights reserved.)

In this study, to clarify the interaction between dissolved heavy metals and the coexisting chemical factors in karst wetland waters, surface water samples were collected from the Caohai Wetland during a water year, and the hydrochemistry and heavy metal pollution characteristics of the samples were analyzed. The main influencing factors of heavy metals in different water periods were identified through a cooccurrence network analysis. To further analyze the influence mechanism of these main influencing factors, the forms of heavy metals in the water were simulated with PHREEQC software, and the effects of these main influencing factors on the forms were analyzed by redundancy analysis. The results show that Ca 2+ was the main cation in the wetland water, while the main anion was HCO 3 - . The hydrochemical facies of the Caohai Wetland in the wet and dry seasons were Ca-Mg-SO 4 -HCO 3 and Ca-HCO 3 , respectively. Cd was the main pollutant in the Caohai Wetland, with Cd levels seriously exceeding the standards. The characteristics of the karst water in the Caohai Wetland are apparent. The cooccurrence network analysis shows that pH, dissolved oxygen (DO), electrical conductivity (EC), SO 4 2- and HCO 3 - are the main factors regulating heavy metals. The results of morphological simulation and analysis were used to explore the mechanism of action of these factors. These data provide geochemical information useful for water quality assessment and management plans on heavy metal pollution., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The blood lead levels (BLLs) of children in China remain notably high in many areas. We aimed to summarise the relevant regional characteristics, identifying problematic areas and the causes of lead pollution. We searched the databases of PubMed, China National Knowledge Infrastructure (CNKI), and Wanfang Data, systematically reviewing 219 articles published from January 2010 to September 2020. In doing so, we assessed the BLLs noted in 220 prefectures across China. Data were organised using Geographic Information Systems (GIS) mapping. Out of a total of 629,627 children sampled, we found that the average blood lead level (BLL) of children included in our study is 50.61 ± 13.63 μg/L, which slightly exceeds the 50.00 μg/L US standard. Within the sample, 8.75% had BLLs higher than 100.00 μg/L. Children living in Liaoning, Hebei, Shanxi, Jiangxi, Anhui, Fujian, Guizhou, Yunnan, and Guangxi had notably high BLLs, at more than 60.00 μg/L. A total of 112 municipalities had an average children's BLL above 50.00 μg/L. Furthermore, Chenzhou, Linfen, Yuncheng, and Hechi had the highest children's BLLs, with average values above 100.00 μg/L. The leading contributors to lead pollution are lead mining, lead recovery and the smelting industry. Nonetheless, the lead-acid battery industry needs more attention. Although data suggest that BLLs are decreasing in China, many areas still have high BLLs that need to be monitored. Moreover, national standards must improve to decrease acceptable BLL thresholds for children., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Owing to its environmental-friendliness, low-cost, and outstanding characteristics, biochar has been widely used for the catalytic degradation of various organic pollutants. In this study, a pre- and post-deashing graphitized biochar (DBC800 and PBC800-A) was prepared and compared with the pristine biochar (PBC800) to activate persulfate (PS) for tetracycline (TC) degradation. The influence of the natural endogenous mineral on the catalytic ability of biochar was investigated. Characterization results show that the inherent endogenous mineral in biochar not only acted as a natural pore-forming agent to promote the formation of the porous structure, but also facilitated the formation of edge defective structures, and altered the surface functional groups, as well as increased the carbonization and graphitization degree of biochar. The PBC800-A exhibited a much higher catalytic efficiency on PS activation and TC oxidative degradation with the reaction rate of 0.06055 min -1 , 7.14 times as that of DBC800 (0.00861 min -1 ) and 4.63 times as that of PBC800 (0.00158 min -1 ). The endogenous minerals were conducive to the generation of free radicals and promoted the oxidative degradation of TC, which was mainly attributed to the improved carbon configuration. The post-deashing treatment was also found to significantly improve the electron transport efficiency of biochar by removing the residual ash, thereby promoting the generation of singlet oxygen. This study demonstrated that the natural minerals in biochar was beneficial for the degradation of TC, and more alternative natural minerals can be applied to co-pyrolysis with biochar for the remediation of refractory organic pollutants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

This study aimed to investigate the response of sediment microbial communities (including bacteria and archaeal groups) in Caohai Lake to anthropogenic activities. The sediment samples were collected from the regions with high anthropogenic interference and low anthropogenic interference. Their physicochemical properties and enzyme activities were analyzed, and the bacterial and archaeal communities were investigated using high-throughput sequencing technology. The results showed that the physicochemical characters changed by anthropogenic activities were the important factors that influenced enzyme activities, alpha diversity, key functional taxa, and community structure. And the impact of anthropogenic activities on microbial communities might follow a non-linear pattern. Furthermore, few significant differences of alpha indices between the high and low disturbed areas, but clear differences of microbial community composition analysis and beta-diversity analysis were observed. The hypothesis was proved that the intensity of anthropogenic impacts in Caohai had not reached the potential thresholds. The best distinguish biomarkers between the two areas and the most related key nodes among the network did not always have a high microbial abundance. The anthropogenic activities might influence the microbial community by affecting a small number of the key taxon in the ecological network. These findings provided a valuable understanding of how sediment microorganisms respond to anthropogenic activities in Caohai Lake., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Microbial fuel cells (MFCs) that are bio-energy transducers capture bioelectricity produced from the oxidation of organic matter by using the electro-active bacteria grown on the biofilm attached on anode. Previous studies explored the effect of several limiting factors, such as electrode material, catalyst type, membrane structure, and electrolyte, on the electrochemical performance of MFCs. However, the effects of electrode position on Cr(VI) reduction and bioelectricity production remain unknown. In this study, MFCs with different electrode positions (i.e., 4 cm (MFC-4), 3 cm (MFC-3), 2 cm (MFC-2), and 1 cm (MFC-1)) were designed and fabricated to evaluate the overall performance of MFCs. The results of electrochemical analysis confirmed that MFC-2 exhibited low exchange transfer resistance (4.9 Ω) and strong conductivity, resulting in optimal electrochemical performance. In addition, Cr(VI) was completely removed within 11 h in MFC-2 with a large reduction rate of 0.91 g/m 3 ·h. and COD removal efficiency of 78.25%. The overall performance of MFC-2 was comparatively higher than those of MFC-1 (0.80 g/m 3 ·h and 68.82%), MFC-3 (0.64 g/m 3 ·h and 61.67%), and MFC-4 (0.52 g/m 3 ·h and 39.85%). Meanwhile, MFC-2 generated high open voltage (1.02 V) and power density (535.4 mW/m 2 ), which are 1.4- and 3.1-fold larger than those of MFC-4 (0.72 V and 171.3 mW/m 2 ). High COD removal and power density indicated the strong electrochemical activity of electroactive bacteria in the anode chamber of the MFCs, which was due to the low resistance in the MFCs could accelerate electron transfer and boost electrochemical reaction. Consequently, the optimal electrode spacing in MFCs was 2 cm. Further studies confirmed that Cr(VI) was removed and deposited in the form of Cr(III) on the electrode surface. High-throughput analysis suggested Pseudomonas species are the key electroactive bacteria for electricity generation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Iron (hydr)oxide-natural organic matter (NOM) colloids, the dominant components of soil, usually occur in varied circumstances and may affect Hg transport and fate in soil. This study aims to reveal the Hg binding to preformed composites rather than only focusing on Hg retention by iron (hydr)oxides in the presence of NOM. Ferrihydrite-humic acid (FH-HA) is chosen as a representative composite, and the effect of the complexation method and FH morphology on Hg binding to various composites is evaluated. Three types of composites are developed: a dense coprecipitated composite (p-d-f), a gel-like adsorbed composite (a-g-f) and a dense adsorbed (a-d-f) composite. Batch sorption and stirred-flow kinetic tests together with surface property analysis and modern spectral analyses are carried out to explore the binding behavior of Hg to the three composites and clarify the interactions in the ternary systems of FH-HA-Hg. The results show that the Hg sorption isotherms all fit well with the Langmuir model, and the maximum sorption capacities follow the order a-g-f> a-d-f > p-d-f, implying that the adsorbed composite is more favorable than the coprecipitated composite for Hg binding and a gel morphology is more beneficial than a dense morphology. The stirred-flow experiments show that the adsorbed composite has a small advantage in Hg sorption compared to the coprecipitated composite and that the gel-like composite can adsorb more Hg at a faster rate than the dense composite. Both FH and HA participate in Hg sorption, and FH-HA-Hg complexes are speculated to form. These findings are helpful to better understand the mobility and fate of Hg in soils, as well as the associated dynamic model for predicting Hg behavior in the environment where the iron (hydr) oxide-NOM composites are pre-existed., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The frequent occurrence of toxin-producing cyanobacteria blooms driven by anthropogenic eutrophication has become a major threat to aquaculture ecosystems worldwide. In this study, the behavior of M. aeruginosa cells during flocs storage period of 6 days was first investigated after pre-oxidation and coagulation of Fe 2+ /PS. Fe 2+ /PS achieved a superior removal efficiency of 90.7% for OD 680 and 90.4% for chl-a. The contents of extracellular MCs in the pre-oxidation and coagulation system were significantly (P < 0.05) lower than those in the control. A significant (P < 0.05) difference in intracellular protein between the control and the coagulated systems was observed. Three-dimensional fluorescence excitation emission matrix (EEM) was employed to investigate the variations in extracellular organic matter (EOM) during flocs storage. The results indicated the presence of four peaks, representing protein-like substances, intermediate dissolved microbial metabolites, fulvic and humic-like compounds in the Fe 2+ /PS process. And the intensities of four peaks were all decreased in the Fe 2+ /PS system compared to those in the control. A low level of accumulated residual Fe of 0.28 mg/L was observed without posing potential environmental risk. The results showed that the M. aeruginosa cells were under stressful conditions after 3-d storage due to the decomposition of extracellular polymeric substances (EPSs) and the insufficient supply of nutrients. However, SEM results indicated that no significant alteration in cell morphology was observed. Therefore, with high removal of M. aeruginosa, low MCs concentrations, and trivial cell damage, the Fe 2+ /PS preoxidation-coagulation was proved to be an environmental-friendly method for cyanobacteria removal without yielding serious secondary pollution. This work will contribute to better understanding and managing the cyanobacteria-laden aquaculture water after pre-oxidation and coagulation., Competing Interests: Declaration of competing interest There are no interests to declare., (Copyright © 2020. Published by Elsevier Inc.)

Biochar (BC) derived from Chinese herbal medicine residues has been investigated for its performance as a potential adsorbent in tetracycline (TC) removal. In the present study, a chemical co-precipitation method was carried out to prepare manganese dioxide modified biochar (Mn-BC) to increase its sorption capacity. The properties of the modified biochar were characterized for further enhancing TC removal from an aqueous solution. Mn-BC was successfully synthesized and resulted in a much higher specific surface area, total pore volume and pore diameter. The sorption kinetics of TC on Mn-BC was described by the pseudo-second-order model. The sorption data of Mn-BC were fitted by Langmuir and Freundlich models. The study findings revealed a maximum adsorption capacity of Mn-BC (1:10) to TC was up to 131.49 mg/g. The adsorption process was endothermic and spontaneous. The degradation of TC was further enhanced by MnO 2 acting as an oxidizer on Mn-BC. Overall, the modified biochar derived from Chinese herbal medicine residues is a superior alternative for the removal of TC from an aqueous solution., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Lead is known as a potent toxicant to human health and there is currently an issue with lead contamination of food in China. This study analysed the regional characteristics of dietary lead intake of the Chinese population and used this to assess the health risks for each region due to the presence of lead in different foods. Data of dietary lead intake was used from the 4th and 5th Chinese Total Diet Studies (CTDS) covering 12 to 20 provinces. Over 200 kinds of food samples were divided and analysed. Results showed that lead consumption varies from region to region, with some, such as Heibei, being at higher risk and consuming larger amounts, and others, such as Shanxi, being at lower risk. It was found that the spatial correlation between lead intake from meats and vegetables was 0.545. The strong association between meats and vegetables shows that lead contamination has a large effect on fresh foods. The food groups with the highest contribution to lead intake were cereals and vegetables, while the food categories with the lowest contribution were dairy products, sugar, and alcohol. The main food group contributing to lead intake in different regions was found to be cereals in Hebei, vegetables in Heilongjiang and Ningxia, and meats in Sichuan and Hunan. The food products contributing the most to lead intake were found to be kelp and nori in many provinces and other notable foods included processed and preserved soybean, meat, and fungus products. These results allow policy makers to better target their efforts when working on the issue of lead contamination, focusing on areas of high contamination, and to advise consumers to adjust their diets to avoid high risk foods as this issue is being resolved., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The effects of using dried sewage sludge as additive on cement property in the process of clinker burning were investigated in this paper. The eco-cement samples were prepared by adding 0.50-15.0% of dried sewage sludge to unit raw meal, and then the mixtures were burned at 1450 °C for 2 h. The results indicated that the major components in the eco-cement clinkers were similar to those in ordinary Portland cement. Although the C(2)S phase formation increased with the increase of sewage sludge content, it was also found that the microstructure of the mixture containing 15.0% sewage sludge in raw meal was significantly different and that a larger amount of pores were distributed in the clinker. Moreover, all the eco-cement pastes had a longer initial setting time and final setting time than those of plain cement paste, which increased as the sewage sludge content in the raw meal increased. All the eco-cement pastes had lower early flexural strengths, which increased as the sewage sludge content increased, while the compressive strengths decreased slightly. However, this had no significant effect on all the strengths at later stages. Furthermore, the leaching concentrations of all the types of eco-cement clinkers met the standard of Chinese current regulatory thresholds., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Landfill leachate was treated by a combined sequential batch reactor (SBR), coagulation, Fenton oxidation and biological aerated filter (BAF) technology. The metals in treatment process were fractionated into three fractions: particulate and colloidal (size charge filtration), free ion/labile (cation exchange) and non-labile fractions. Fifty percent to 66% Cu, Ni, Zn, Mn, Pb and Cd were present as particulate/colloidal matter in raw leachate, whereas Cr was present 94.9% as non-labile complexes. The free ion/labile fractions of Ni, Zn, Mg, Mn, Pb and Cd increased significantly after treatment except Cr. Fifty-nine percent to 100% of Al was present mainly as particulate/colloidal matter >0.45 μm and the remaining portions were predicted as non-labile complexes except in coagulation effluent. The speciation of Fe varied significantly in various individual processes. Visual MINTEQ simulation showed that 95-100% colloidal species for Cu, Cd and Pb were present as metal-humic complexes even with the lower dissolved organic carbon. Optimum agreements for the free ion/labile species were within acidic solution, whereas under-estimated in alkaline effluents. Overestimated particulate/colloidal fraction consisted with the hypothesis that a portion of colloids in fraction <0.45 μm were considered as dissolved., (Copyright © 2011 Elsevier B.V. All rights reserved.)

A novel nanoscale photocatalyst CNTs/P-TiO(2) was successfully prepared by hydrothermal method. The morphology and the physicochemical properties of the prepared samples were investigated using TEM, XPS, XRD, BET, FTIR, TG-DSC and UV-vis DRS spectroscopy. The photocatalytic activity was evaluated by degradation of methyl orange (MO) dye. The results demonstrated that CNTs/P-TiO(2) nanoparticles could effectively photodegrade MO not only under UV irradiation but also under visible-light (VL) irradiation. The MO degradation performance on CNTs/P-TiO(2) was superior to that of the commercial P25. The optimal mass ratio of CNTs to P-TiO(2) in the nanocomposite catalyst was 5:100. The synergetic effect was discussed in terms of different roles played by phosphorus doping and introducing CNTs into the composite catalysts., (Copyright © 2010. Published by Elsevier B.V.)

In this study, the Fenton process was found to be successful to treat landfill leachate rejected after reverses osmose treatment. Central composite design (CCD) and response surface method (RSM) were applied to evaluate and optimize the interactive effects of three operating variables, initial pH and dosages of H(2)O(2) and Fe(2+) on physical and oxidative performances of Fenton process. Six dependent parameters such as overall chemical oxygen demand (COD) removal, COD removals of oxidation and coagulation, mineralization, humic substances (HS) removal and sludge volume ratio (SVR) were either directly measured or calculated as responses. According to analysis of variances (ANOVA) results, six proposed models could be used to navigate the design space with high regression coefficient R(2) varied from 0.9489 to 0.9988. It was found that initial pH, H(2)O(2) and Fe(2+) dosage had significant effects on the overall COD removal, mineralization and HS removal due to their respective effects on the oxidation and coagulation removals. Synergies effect of oxidation and coagulation during Fenton process controlled the treatment. The visual search of overlaying critical response contours plot was demonstrated. The results indicated the optimum conditions to be 3.64 of initial pH, 100 mM of Fe(2+) and 240 mM of H(2)O(2) dosage, respectively. The experimental data and model predictions agreed well. The overall COD removal, COD removals of oxidation and coagulation, mineralization, HS removal and SVR of 71.81%, 46.22%, 25.80%, 63.81%, 91.53% and 3.50 ml/mM were demonstrated., (Copyright 2010 Elsevier B.V. All rights reserved.)

The degradation of humic acid (HA) was carried out in the presence of the Fenton reagent. The experiments demonstrated that HA was removed by oxidation and coagulation. Moreover, the oxidation occurred mainly at the first 60 min and predominated the HA removal efficiency. A new kinetic model was established according to the generally accepted mechanism of high active OH oxidation in order to well describe the Fenton oxidation reaction in HA aqueous solution. The model embraced two key operating factors affecting the HA degradation in Fenton process, including the dosages of hydrogen peroxide and ferrous ion. The experimental data were fitted by using the most commonly used first- and the second-order reaction models and the new model, respectively. The goodness of fittings demonstrated that the new model could better fit the experimental data than the other two models, which indicated that this analytical model could better describe the kinetics of Fenton reaction mathematically and chemically. Results indicated that the oxidation rate and removal efficiency were strongly dependent on initial pH, initial concentration of Fenton reagents, initial HA concentration and reaction temperature. The experiments demonstrated that hydrogen peroxide and ferrous ion would approach their saturated value with increasing dosage., (2010 Elsevier B.V. All rights reserved.)

A set of anaerobic-anoxic-aerobic (A(2)/O) bioreactor system was designed and used to treat domestic wastewater mixed with landfill leachate in Datansha Sewage Treatment Plant in Guangzhou, south China. The optimal mixing proportion of combined treatment of domestic wastewater with landfill leachate and the optimal operating conditions for the removal efficiencies of nitrogen by using Taguchi orthogonal array test was conducted to evaluate the influence of parameters. The results showed that: the optimal volume ratio of landfill leachate and domestic wastewater in the A(2)/O process was 1:500. The average removal efficiencies of NH(4)(+)-N, TN and COD was achieved to be 96.5%, 61.0% and 81.7%, respectively in the case of the hydraulic retention time (HRT) of 11h, dissolved oxygen (DO) of 3 mg L(-1), the mixed-liquid return ratio (r) of 200% and sludge return ratio (R) of 80% in the case of the confirmatory experiment. The pilot scale (3.8m(3)) investigation results were applied in the large-scale (220,000 m(3)/d) combined treatment of sewage wastewater with landfill leachate in Guangzhou Datansha Domestic Sewage Wastewater Treatment Plant. The removal efficiencies of COD, NH(4)(+)-N, T-N and T-P were 82.65%, 92.69%, 57.10% and 76.55%, respectively., (Copyright 2010 Elsevier B.V. All rights reserved.)

A laboratory testing of simultaneous removal of ammonium and sulfate (SRAS) was studied from an anammox process in an anaerobic bioreactor filled with granular activated carbon. Two different phases of experiment were investigated to start up the SRAS process, and final batch tests were performed to analyze the SRAS process. The experiment included an anammox process and an SRAS process. During the anammox process, the highest removal efficiency of ammonium and nitrite was up to 97 and 98%, respectively. After 160 days in the stationary phase of anammox process, the ratio of ammonium to nitrite consumption was approximately 1:1.15, which is much higher than 1:1.32 in the traditional anammox process. The extra electron acceptor, such as sulfate, was thought to react with ammonium by bacteria. Synthetic wastewater containing ammonium chlorine and sodium sulfate was used as the feed for the bioreactor in the second phase of experiment. During the SRAS process, the influent concentrations of ammonium and sulfate were controlled to be 50-60 and 210-240 mg L(-1) respectively. After start-up and acclimatization of this process for 60 days, the average effluent concentrations of ammonium and sulfate were 30 and 160 mg L(-1), respectively. The simultaneous ammonium and sulfate removal was detected in the reactor. In order to further validate the biochemical interaction between ammonium and sulfate, batch tests was carried out. Abiotic tests were carried out to demonstrate that the pure chemical action between ammonium and sulfate without microorganism was not possible. Biotic assays with different ammonium and sulfate concentrations were further investigated that high concentrations of ammonium and sulfate could promote simultaneous removal of ammonium and sulfate. And elemental sulfur and nitrogen gas as the products measured in the SRAS process helped to demonstrate the occurrence of new interaction between nitrogen and sulfur. The new process of SRAS in the inorganic condition, including simultaneous removal of ammonium and sulfate, and the appearance of elemental sulfur and nitrogen gas as the terminal products, widened the cycle approach between nitrogen and sulfur.