Phosphate recovery from water and wastewater serves as a feasible alternative to the exploitation of scarce phosphate rock resources. Currently, phosphate is recovered using adsorption-based techniques due to their desirable features, such as a low running cost, feasible operation, and high efficiency. Clay minerals (CMs), a group of earth-abundant resources, have attracted increasing interest in phosphate management. However, because the surface and crystal lattice of CMs are negatively charged, CMs are inefficient and have been replaced with cost-effective modified CMs (mCMs). This review comprehensively covers the current advances in mCM-mediated phosphate recovery. We first discussed the crystal features of natural CMs and the diverse techniques used for mCMs to enhance their phosphate-removal capacity. Subsequently, we covered the processes of mCM-driven phosphate management, namely, ion exchange, hydrogen bonding, crystallization, Lewis acid-base interactions, electrostatic interactions, precipitation, and electrostatic-ligand exchange. Further assessments revealed that mCMs can efficiently remove phosphate through multiple synergistic mechanisms. This review also discussed the effects of anions, humic acids, and cations on the mCMs management of phosphate and analyzed mCMs applications in various water environments, specifically, phosphate passivation materials in lake sediments and the phosphate management of municipal/seawater wastewater. We examined the reutilization of phosphate-loaded mCMs in agriculture from a circular economy perspective, and finally discussed the commercial application prospects of mCMs in environmental pollution remediation, which may help to avert the global phosphate-resource crisis and improve wastewater management.

The capture of CO 2 has become a global research focus. Rock weathering in the natural environment makes significant contributions to the stable carbon capture at both long and short time scales. However, traditional methods of estimating carbon capture potential are still uncertain due to the solely instantaneous carbon capture rates, dependence of measured data, and difficulty in predicting future carbon sink potential. Here, the estimated carbon capture potential of rock weathering using conventional methods and the PROFILE weathering model were compared for the various rocks in subtropics in China. The results showed that the carbon capture rates estimated by the GEM-CO 2 model vary from 1.64 to 27.40 mmol·m − 2 ·d − 1 , while 2.63 ~ 13.46 mmol·m − 2 ·d − 1 by traditional the water chemistry method. Similarly, carbon capture rates calculated by the PROFILE model based on chemical weathering rate of individual specific mineral, ranging from 0.03 to 19.03 mmol·m − 2 ·d − 1 . The results of the PROFILE calculation showed that, the carbon capture rate was 1.30 to 1.99 times in summer than in winter due to the higher temperature and precipitation. In extreme climates, high temperatures (≥ 30°C) and heavy precipitation (≥ 25mm) have increased the capture rate of carbon dioxide by approximately 21.33% and 66.23%, respectively. On the interdecadal time scale, the carbon capture rate increased by 6.1% from 1970 to 2020, due to temperature rising by 1.4°C, precipitation increasing by 2.8%, and partial pressure of atmospheric carbon dioxide ( pco 2 ) increasing by 28.4%. Further, we predict an increase in carbon capture rates will change approximately from 4.7 to 5.1% in the period of 2020–2100 under four Representative Concentration Pathway (RCP) modes. The findings of this study will offer novel scientific recommendations and methods for future research and policy making on global carbon neutrality.

Adsorption, which is a quick and effective method for phosphate management, can effectively address the crisis of phosphorus mineral resources and control eutrophication. Phosphate management systems typically use ironcontaining nanominerals (ICNs) with large surface areas and high activity, as well as modified ICNs (mICNs). This paper comprehensively reviews phosphate management by ICNs and mICNs in different water environments. mICNs have a higher affinity for phosphates than ICNs. Phosphate adsorption on ICNs and mICNs occurs through mechanisms such as surface complexation, surface precipitation, electrostatic ligand exchange, and electrostatic attraction. Ionic strength influences phosphate adsorption by changing the surface potential and isoelectric point of ICNs and mICNs. Anions exhibit inhibitory effects on ICNs and mICNs in phosphate adsorption, while cations display a promoting effect. More importantly, high concentrations and molecular weights of natural organic matter can inhibit phosphate adsorption by ICNs and mICNs. Sodium hydroxide has high regeneration capability for ICNs and mICNs. Compared to ICNs with high crystallinity, those with low crystallinity are less likely to desorb. ICNs and mICNs can effectively manage municipal wastewater, eutrophic seawater, and eutrophic lakes. Adsorption of ICNs and mICNs saturated with phosphate can be used as fertilizers in agricultural production. Notably, mICNs and ICNs have positive and negative effects on microorganisms and aquatic organisms in soil. Finally, this study introduces the following: trends and prospects of machine learningguided mICN design, novel methods for modified ICNs, mICN regeneration, development of mICNs with high adsorption capacity and selectivity for phosphate, investigation of competing ions in different water environments by mICNs, and trends and prospects of in-depth research on the adsorption mechanism of phosphate by weakly crystalline ferrihydrite. This comprehensive review can provide novel insights into the research on highperformance mICNs for phosphate management in the future.

The environmental capacity of agro-ecosystem is the basis of sustainable development of agriculture, but this is hard to evaluate quantitatively due to complex input and output processes of heavy metals. Therefore, in this study, leaching of heavy metals based on PROFILE weathering model were integrated into the steady-state critical load (SSCL) of heavy metals. The results showed that the leaching rates of Hg, As, Cd, Cr, Pb, Cu and Zn in paddy soil were 0.08, 4.69, 0.22, 44.31, 18.13, 21.96 and 64.42 g/ha ‧a, respectively, while the leaching rates were significantly correlated with pH, CaO, TFe2O3 and Corg.. Atmospheric deposition was the main input source of heavy metals in agricultural soil, while rice plant uptake and leaching were the main output pathways. The spatial distribution of SSCL were mainly affected by the content of heavy metals in soil, Aw (specific area of soil mineral), and & rho; (bulk density). Values of SSCL hardly changed after about 40 years (Hg es 0.02 kg/ha, Ases0.60 kg/ha, Cd es 0.07 kg/ha, Cr es 5.59 kg/ha, Pb es 3.55 kg/ha, Cu es 1.49 kg/ha and Zn es 4.45 kg/ha). However, the sensitivity analysis indicated that soil leaching had 24.30%-27.90% positive effects on SSCL model. Based on the relationship among leaching, pH, standard limit and SSCL of heavy metals, the standard limit could be appropriately raised to cope with the increased human activities on the premise of the ecological capacity. Thus, the SSCL model provides a new insight for the establishment of environment management in agricultural soils.

Glacial sediments as an important end member of the global dust system, could indicate changes in global climate, aerosols sources, ocean elements, and productivity. With global warming, ice caps shrinking and glaciers retreat at high latitudes have attracted concern. To understand the response of glacier to environment and climate in modern high latitude ice-marginal environments, this paper investigated glacial sediments in the Ny-Ålesund region of the Arctic and clarified the response of polar environmental to global changes through geochemical characteristics of glacial sediments. The results showed that: 1) main factors affecting the elements distribution of the Ny-Ålesund glacial sediments were thought as soil formation, bedrock and weathering, and biological activity; 2) variations of SiO2/Al2O3 and SiO2/Al2O3 + Fe2O3, indicating low weathering of the soil. The ratio of Na2O/K2O indicating a weak chemical weathering, was negatively correlated to the CIA. With the average CIA of Ny-Ålesund glacial sediments for main minerals of quartz, feldspar, and muscovite as well as dolomite and calcite 50.13, which implied glacial sediments at the early stage of chemical weathering and depletion of Ca and Na; 3) the separating effect of stones and soils by stone circle formation due to thermal conductivity and frost heave makes sediments in stone circle have lower chemical weathering with only two main minerals, albite and quartz; 4) changes of carbonate content in sediments with glacier front retreating in different period implied that weathering rate of calcite averagely reached an estimate of 0.0792%wt/year in glacier A. The succession of vegetation made biological weathering become an important driving force for carbonate leaching from glacial sediments. These results and data provide scientifically significant archive for future global change studies.

The electroplating wastewater containing various metal ions was treated by adding sodium dodecyl benzene sulfonate (SDBS) and regulating pH value, and the resulting precipitates were characterized by X-ray diffraction (XRD). The results showed that organic anions intercalated layered double hydroxides (OLDHs) and inorganic anions intercalated layered double hydroxides (ILDHs) were in-situ formed to remove heavy metals during the treatment process. In order to reveal the formation mechanism of the precipitates, SDB− intercalated Ni–Fe OLDHs, NO3− intercalated Ni–Fe ILDHs and Fe3+-DBS complexes were synthsized by co-precipitation at various pH values for comparison. These samples were characterized by XRD, Fourier Transform infrared (FTIR), element analysis as well as the aqueous residual concentrations of Ni2+ and Fe3+ were detected. The results showed that OLDHs with good crystal structures can be formed as pH≤7, while ILDHs began to form at pH = 8. When pH < 7, complexes of Fe3+ and organic anions with the ordered layered structure were formed firstly, and then with increase in pH value, Ni2+ inserted into the solid complex and the OLDHs began to form. However, Ni–Fe ILDHs were not formed when pH ≤ 7. The Ksp (Solubility Product Constant) of OLDHs was calculated to be 3.24 × 10−19 and that of ILDHs was 2.98 × 10−18 at pH = 8, which suggested that OLDHs might be easier to form than ILDHs. The formation process of ILDHs and OLDHs were also simulated through MINTEQ software, and the simulation output verified that OLDHs could be easier to form than ILDHs at pH ≤ 7. Information from this study provides a theoretical basis for effective in-situ formation of OLDHs in wastewater treatment.

The lamella aggregation state of layered double hydroxides (LDHs) may affect their sorption capacity for organic compounds. The dried LDH samples (Ni/Cr LDH-FA-D and Ni/Cr LDH-H2O-D) and the undried samples (Ni/Cr LDH-FA-W and Ni/Cr LDH-H2O-W) were flexibly prepared by a co-precipitation method in formamide (FA) and water, respectively. The results of X-ray diffraction (XRD) and transmission electron microscope (TEM) showed that the undried LDHs were unassembled, which had no the stacking layers but had a pseudohexagonal nanosheet lamella structure. And the unassembled LDH layers can be assembled again during the dry process. Ni/Cr LDH-FA-W and Ni/Cr LDH-H2O-W showed much greater adsorption capacities towards methyl orange (MO) than Ni/Cr LDH-FA-D and Ni/Cr LDH-H2O-D, as well as shorter time to reach equilibrium. The maximum adsorption capacity of MO could be calculated to 806 mg/g and 740 mg/g for Ni/Cr LDH-FA-W and Ni/Cr LDH-H2O-W by Langmuir-type simulation. The greater adsorption capacities of unassembled LDH could be attributed to the loosen structure and much more exposed adsorption sites. It could be concluded that unassembled LDHs were an effective and conducive preparation pathway for the exploration of the adsorption sites of LDHs. (c) 2022 Elsevier Inc. All rights reserved.

Excess bisphenol A (BPA) is a pollutant of concern in different water sources. In this work, magnetic illite clay-composite material (Fe3O4@illite) was synthesized via the coprecipitation method by loading Fe3O4 nanoparticles (nano-Fe3O4) onto the surfaces of illite clay. Results from different characterizations showed that nano-Fe3O4 was embedded into illite clay nanosheets and existed on the surfaces of illite clay, thereby reducing the degree of agglomeration and improving dispersibility. The catalytic BPA degradation of Fe3O4@illite and nano-Fe3O4 confirmed the superior performance of Fe3O4@illite compared with that of nano-Fe3O4. The optimum operating parameters for degradation were 0.3 mL of H2O2 at pH of 3 in the presence of Fe3O4@illite, which provided a maximum degradation capacity up to 816, 364, 113, and 68 mg/g for epoxy BPA concentration of resin wastewater (266 mg/L), synthetic wastewater (80 mg/L), Hefei City swan lake (25 mg/L), and Hefei University lake wastewater (14.94 mg/L), respectively, in 180 min reaction time. The degradation data conformed to the pseudo-first-order kinetic model. The degradation pathways and mineralization study revealed that the adsorption-Fenton-like reaction was the principal mechanism that demonstrated 100% degradation efficiency of Fe3O4@illite even after nine successive runs. The regeneration and reusability tendency analysis ensured that Fe3O4@illite can be easily separated by using magnets. Therefore, Fe3O4@illite composite with H2O2 Fenton-like technology was a promising method for BPA degradation. (C) 2020 Elsevier Ltd. All rights reserved.

As one of the most popular beverages around world, factors influencing transfer of heavy metals from soil to tea leaves is crucial to investigate and assess health risk through tea drinking.Parent material (PM), soil and tea samples from Anhui province, typical tea producing area in China were collected in this study.To find out distribution characteristics of heavy metals in tea and soil, and influencing factors for transfer process, variables of plantation factors, soil properties and geological background were taken into account.The results showed that weathering pedogenic process could be the main release source of heavy metals in soil under the acid environment for tea growth.More than 75% of soil Cd, Hg, Pb and Zn exceeded background.However heavy metals in tea samples were below the limits of China, WHO and EU standards.Soil organic matter and redox process influenced the distribution and transfer of As, Pb, Cd and Hg in soil and tea.While geochemical behaviours of Cr, Cu, Ni and Zn were mainly related to soil pH and iron oxides in tea garden.The method of classification and regression trees (CART) showed clones of tea type, bedrock type, soil texture, soil organic and fertilizer application were identified as the main factors influencing transfer factors of heavy metals from soil to tea.The specific types of tea grown in the soil with sandy clay and bedrock of granite/granodiorite and shale should be given more monitoring.The non-carcinogenic hazard quotients (HQ) and cancer risk (Risk) through tea drinking were primarily caused by Pb and Cd respectively.To reduce the potential health risk from tea, application of organic and/or compound fertilizer were thought to be the effective management strategy for tea plantation.

P-chlorophenol (P-CP) is a recalcitrant toxicant in wastewater. Recently, the use of composite materials and environmentally friendly technology in the degradation of pollutants in wastewater has attracted widespread attention. For the first time, the nano zerovalent iron nano zerovalent iron (NZVI)-loaded muscovite (NZVI@ muscovite), a novel composite material, was synthesized by liquid-phase reduction. The different physico-chemical properties of NZVI@muscovite indicated that the muscovite could support NZVI of 40-50 nm sizes. The NZVI@muscovite had a low agglomeration degree, good dispersibility, and improved catalytic activity. In addition, the optimization experiments of P-CP degradation demonstrated that NZVI@muscovite actively degraded P-CP at a pollutant:catalyst ratio of 714 mg:1 g. This ratio was higher than that of the other composite materials under optimal operating conditions. Adsorption and degradation by Fenton-like reaction were the main mechanisms underlying P-CP degradation. This study extended the use of NZVI@muscovite as an efficient composite material for the degradation of P-CP in an aqueous environment.

Reduction of iron ore directly by H-2 has been developed as an alternative technology for iron production, which can alleviate pollutant emissions by eliminating the needs of cokemaking and sintering processes. However, the behaviour of trace elements (especially the volatilisation of heavy metal(loid)s) in iron ore during reduction by H-2 is still unclear and the relevant research is scarce in literature. This study aimed to provide an insight into the volitilisation behaviour of trace elements and the environmental assessment during reduction of Australian iron ore with H-2 from room temperature to 1000 degrees C. The trace element concentrations in the iron ore at different reduction tempatures were analysed along with changes in chemical structure and surface morphology using X-ray diffraction, Fourier transform infrared spec-troscopy, Raman spectroscopy and scanning electron microscopy. Results showed that the extent of As, S, Li, Sn and Pb volatilisation varied with temperature with nil, 22%, 82%, 82% and 72% respectively remaining in the sample at 1000 degrees C. Simutaneously, stepwise reduction of iron ore (goethite / wustite) with temperature was confirmed. Pearson's method of correlation was employed to determine the correlations between pairs of key indexes (LOI 1000, mass loss%, O loss% and loss ratios of elements) of goethite reduction. Results indicated that S loss exhibited a high correlation (r = 0.977) with Pb loss, implying the simultaneous volatilisation of Pb and S as well as possible presence of Pb and S-containing compounds, such as PbS in the sample. Li and Sn showed the coincidental simultaneous volatilisation as indicated by the highest correlation (r = 1.000 with p < 0.01). The kinetic analysis indicated that the volatilisation of above elements best fitted diffusion models (D1 or D3) with activation energy (E) ranging within 11.65-26.75 kJ/mol. Risk assessment analysis demonstrated a much higher risk score of iron ore reduciton at 1000 degrees C (value of 94.758) than 200 and 500 degrees C (value of 1-3) due to obvious volatilisation of As and Pb at high temperature. Life cycle impact assessment (LCIA) data confirmed four valid impact categories with human toxicity being the most significnat with the major contribution ascribed to As element. Generally, the hazardous elements released from the ore reduction process can be eliminated before their discharge to the environment. (C) 2020 Elsevier Ltd. All rights reserved.

Bisphenol A (BPA) is a toxic environmental pollutant commonly found in wastewater. Using non-toxic materials and eco-friendly technology to remove this pollutant from wastewater presents multiple advantages. Treatment of wastewater with clay minerals has received growing interest because of the environment friendliness of these materials. Bentonite is a 2:1 layered phyllosilicate clay mineral that can support nano-metal catalysts. It can prevent the agglomeration of nano-metal catalysts and improve their activity. In this article, a green catalytic nano zero-valent iron/bentonite composite material (NZVI@bentonite) was synthesized via liquid-phase reduction. The average size of NZVI was approximately 40-50 nm. Good dispersion and low aggregation were observed when NZVI was loaded on the surface or embedded into the nanosheets of bentonite. Degradation of BPA, a harmful contaminant widely found in wastewater at relatively high levels, by NZVI@bentonite was then investigated and compared with that by pristine NZVI through batch Fenton-like reaction experiments. Compared with pristine NZVI and bentonite alone, the NZVI@bentonite showed a higher BPA degradation ratio and offered highly effective BPA degradation up to 450 mg/g in wastewater under optimum operating conditions. Adsorption coupled with the Fenton-like reaction was responsible for BPA degradation by NZVI@bentonite. This work extends the application of NZVI@bentonite as an effective green catalyst for BPA degradation in aqueous environments.

Due to abundant biomass and eco-friendliness, biochar is exemplified as one of the most promising candidates to mediate the degradation of environmental contaminants. Recently, environmentally persistent free radicals (EPFRs) have been detected in biochars, which can activate S2O82- or H2O2 to generate reactive oxygen species for effective degradation of organic and inorganic contaminants. Comprehending the formation mechanisms of EPFRs in biochars and their interactions with contaminants is indispensable to further develop their environmental applications, e.g., direct and indirect EPFR-mediated removal of organics/inorganics by biochars. With reference to the information of EPFRs in environmental matrices, this article critically reviews the formation mechanisms, characteristics, interactions, and environmental applications of EPFRs in biochars. Synthesis conditions and loading of metals/organics are considered as key parameters controlling their concentrations, types, and activities. This review provides new and important insights into the fate and emerging applications of surface-bound EPFRs in biochars.

In this study, autoclaved aerated concrete particles (AACPs) from construction waste were used to simultaneously remove phosphorus and nitrogen in biological aerated filters (BAFs). The effects of air/water (A/W) ratio on the removal performance of phosphorus (PO43-), total organic carbon, total nitrogen (TN), and ammonia nitrogen were investigated. Results showed that AACP BAF was more efficient than commercially available ceramsite (CAC) BAF. For example, the removal rates of TN with AACP and CAC were 45.96% and 15.64%, respectively, and those of PO43- with AACP and CAC were 72.45% and 33.97%, respectively, at the A/W ratio of 3:1. Different characterization methods were utilized to evaluate the surface shape, elemental compostion, and internal and surface structure of AACP. The interconnectivity and uniformity of pores and the rough surface of AACP were found to be suitable for the growth of microbial biofilm. In addition, the growth of internal pores in AACP promoted the removal of phosphorus and nitrogen. The surface of used AACP contained a small amount of irregular crystals and was covered with a layer of aggregates, which were characterized as hydroxyapatite [HAP, Ca-5(OH)(PO4)(3)]. The formation of HAP as a final byproduct confirmed the successful removal of phosphorus. Therefore, construction wastes, such as AACPs, could be recycled and utilized as a promising biofilter media for excellent wastewater treatment.

Clay minerals, as abundant natural resources, are among the most suitable supporting materials for nano metal. In this manuscript, new Fe3O4 nanoparticle/rectorite (Fe3O4/rectorite) catalysts are developed via in-situ precipitation oxidation reaction. Various physicochemical characterizations of Fe3O4/rectorite show that Fe3O4 nanoparticles (nano-Fe3O4) with an average particle diameter of approximately 10-20 nm are effectively loaded on the surface of acid leached rectorite (Al-rectorite) and have low coaggregation and improved dispersion. Moreover, the catalytic activity of Fe3O4/rectorite on degradation of P-chlorophenol by heterogeneous Fenton method is studied. Results of degradation experiments show that Fe3O4/rectorite has higher degradation efficiency of P-chlorophenol than bare nano-Fe3O4. Regeneration studies also show that Fe3O4/rectorite maintains 100% of its maximum P-chlorophenol degradation capacity after seven consecutive cycles. Fe3O4/rectorite can be easily separated by magnetic separation, and thus has good stability and reusability. The degradation mechanism of Fe3O4/rectorite is adsorption coupled with a Fenton-like reaction, which accounts for P-chlorophenol degradation of up to 625 mg/g. This work demonstrates a new composite material for the effective remediation of refractory organic compounds from wastewater.

Recently unclassified boards with varying composition and more notably with ambiguous thermal properties are being used in buildings. The fire performance of Light gauge Steel Frame (LSF) wall systems mainly depends on the protective plasterboard linings used and thus fire safety concerns are being raised. Therefore this study was aimed at setting minimum standards for fire-resistant grade plasterboards used in LSF wall applications based on material characterization, thermo-physical properties and finite element heat transfer modelling. The most commonly used fire protective board, gypsum plasterboard was used to address this critical issue. Thermo-physical properties of three gypsum plasterboards manufactured in Australia were measured and compared in relation to their chemical composition in the first phase of the study. Fire resistance levels (FRLs) of LSF wall systems lined with these three plasterboards were determined using 3-D FE heat transfer models of LSF wall systems developed and validated in this study. The paper proposes a "k-factor" based on thermo-physical properties and thickness of plasterboard, capable of giving an overall measure of the fire performance of plasterboard lined LSF walls. Standard k-factor profiles were established for non-load bearing LSF wall systems with FRLs of 60, 120, 180 and 240 min by considering the correlation between the time-temperature profiles from numerical analyses and calculated k-factors. These proposed standard k-factor profiles give an overall measure of the fire performance of plasterboards. This paper presents the details of this study and the results.

Direct reduced iron (DRI) technologies have been developed as an alternative route for iron production alleviating the need for separate cokemaking and sintering operations. This study aimed to provide an insight into DRI production using H2 in terms of elemental content change and chemical structure evolution for improved environmental control of the process. In this work, a sample of goethite was treated from room temperature to 1000 degreesC in 10 vol% H2 in helium in a fixed-bed reactor. The investigated elements were divided into three groups: i) major elements (Fe and Al), ii) alkali and alkaline earth metal elements (mainly Na, K and Ca), iii) transition and post-transition metals (Ni, Cu, Zn, Pb, Cd, etc.) and iv) non-metal and metalloid elements (P, S, As, etc.) The elemental changes of iron ore with temperature were firstly determined by X-ray fluorescence (XRF) analysis and inductively coupled plasma-mass spectrometry (ICP-MS). X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR) and Raman spectrometry were employed to confirm the reactions and investigate the iron ore's chemical changes during direct reduction. XRD analysis indicated the stepwise reduction of goethite → hematite → magnetite → wustite for the goethite sample. FT-IR and Raman spectrometry revealed the transformation of chemical groups with temperature. Results showed that no obvious changes could be noticed after heating the sample to 200 degreesC in terms of the elemental contents and chemical structure. Further treatment of the sample to 500 degreesC and subsequently 1000 degreesC resulted in the content changes of some elements due to the weight loss of hydrated water by heating and reduction of the ore sample, respectively.

A zero-valent iron/rectorite nanocomposite (NZVI/rectorite) was developed as a heterogeneous H2O2 catalyst for P-chlorophenol degradation. The physicochemical properties of NZVI/rectorite were characterized by various techniques including X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive spectrometry, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller analysis. Results showed that NZVI sphere nanoparticles were successfully loaded on the rectorite surface with less aggregation and good dispersion. Moreover, compared with acid-leached rectorite (30.91 m(2)/g), the NZVI/rectorite appeared to have larger surface area (50.75 m(2)/g). In addition, the effects of pH, reaction time, initial P-chlorophenol concentration, catalyst amount, and H2O2 dosage on the P-chlorophenol degradation were systematically investigated. Results showed that NZVI/rectorite presents better properties for the degradation and mineralization of P-chlorophenol compared with pristine NZVI due to the large surface area, low aggregation, and good dispersion of the former. The degradation mechanisms of P-chlorophenol by NZVI/rectorite were adsorption and reduction coupled with a Fenton-like reaction. Four successive runs of the stability and regeneration study also showed that the NZVI/rectorite were unchanged even after 100% of P-chlorophenol degradation ratio. This study has extended the application of NZVI/rectorite as environment function material for the removal of P-chlorophenol from the environment. (C) 2019 King Saud University. Production and hosting by Elsevier B.V.

Ammonium (NH4+) has been causing severe environmental pollution while the development of material with high capacity for ammonium removal remains a challenge. Herein, the cement-based material tricalcium aluminate (C(3)A) was employed to remove NH4+ from digested piggery wastewater. The conditions influencing the removal capacity were investigated, including contact time, initial ammonium concentration, temperature, dosage and initial co-existing phosphate concentration. The physicochemical structure of C(3)A and the resultant were characterized by X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and N-2 adsorption-desorption isotherms. The maximum removal capacity of NH4+ by C(3)A was 155.4 mg.g(-1) at 298 K. The characterization revealed that the resultant was CaAl-Cl-LDH. The hydroxyl groups and Al(OH)(4)(-) from the C(3)A hydration played an important role in ammonium removal. High alkalinity could enhance the removal capacity. This work presents an efficient solution for ammonium removal, thus providing new insight into the mechanism of cement-based materials for water pollutant removal.

Magnetic biochar (MBC) was prepared by the pyrolysis of wheat straw and natural hematite in nitrogen. The effect of the pyrolysis temperature and time was considered. The as-prepared MBCs were characterized by using XRD, FTIR, BET, XPS, and a magnetic susceptibility device. The performance of the prepared MBCs on the removal of Pb(II) was evaluated. The effect of the contact time, pH value, and initial Pb(II) concentration on the adsorption capacity of Pb(II) by the MBCs was investigated. The results show that porous MBCs were successfully prepared by the pyrolysis method. The pyrolysis temperature and time controlled the pore structure, surface area, valence state of iron and magnetic susceptibility of the prepared MBCs. The prepared MBC800-120 exhibited the best Pb(II) adsorption capacity (196.91 mg/g). Moreover, the former still displayed excellent solid-liquid separation efficiency by magnetic separation due to strong magnetism. The hydrolysis-induced precipitation of PbOHCl and the surface complexation by the active sites on the surface of biochar and corroded iron were proposed as the main removal mechanisms. The experimental results provide a novel method for preparing magnetic carbon material and enhancing the comprehensive utilization of biomass and hematite.