Remarkably Enhanced Phosphate Sequestration from Waters by Biochar with High-Density Quaternary Ammonium Groups.

A new biochar (N-BC) was fabricated by incorporating high-density positively charged quaternary ammonium groups into the pristine biochar without any adsorption for phosphate. N-BC can highly efficiently remove phosphate with an optimal pH of 5.0, a maximum experimental adsorption capacity of 30 mg of P/g, and an adsorption equilibrium time of 180 min. The predicted pore diffusion coefficient D (the diffused surface area of the adsorbate for unit time) for phosphate adsorption by N-BC was 5.3 × 10-9 cm2/s. N-BC can still capture phosphate in the copresence of anion Cl- with a molar concentration 50 times that of phosphate. The exhausted N-BC was completely regenerated using a 10 wt % NaOH solution and further reused without any observable loss in adsorption capacity. Moreover, N-BC yielded ∼324 bed volumes (BV) of wastewater containing 1 mg P/L phosphate and 50 mg/L Cl- before breakthrough occurring (<0.1 mg P/L in effluent) in a fixed-bed column operation system. The introduced quaternary ammonium groups covalently bound to biochar played a dominant role in phosphate sequestration by N-BC through forming the out-sphere complexation with phosphate. All results imply that it is of promising prospect for N-BC practical application for phosphate purification from waters. The present study provided a new strategy to expand the application of biochar, usually serving as an adsorbent for cationic pollutants, to the purification of anionic pollutants such as phosphate from waters.

Enhanced interfacial effect via acid theory with boosted photocatalytic performance of nitenpyram removal.

Surface reaction is a prominent aspect that affects the efficiency of photocatalysis. In this work, acid theory was employed to facilitate the reaction dynamics and enhance the interfacial effect between photocatalysts and target molecules. The photocatalytic removal efficiency of NTP was 66 % for bare CdS in 50 min with apparent rate constants of 0.023 compare to 96 % with apparent rate constants of 0.065 for 5% Ce-CdS. The introduced Ce atom as bifunctional active site reduces the energy barrier of O2 adsorption, strengthens the interfacial effect and accelerates the electrons transfer, which could facilitate surface reaction process and boost the photocatalytic performance.

In Situ Fabrication of CdS/Cd(OH)2 for Effective Visible Light-Driven Photocatalysis.

Photocatalytic hydrogen production is a promising technology that can generate renewable energy. However, light absorption and fast electron transfer are two main challenges that restrict the practical application of photocatalysis. Moreover, most of the composite photocatalysts that possess better photocatalytic performance are fabricated by various methods, many of which are complicated and in which, the key conditions are hard to control. Herein, we developed a simple method to prepare CdS/Cd(OH)2 samples via an in situ synthesis approach during the photocatalytic reaction process. The optimal hydrogen generation rate of CdS/Cd(OH)2 that could be obtained was 15.2 mmol·h-1·g-1, greater than that of CdS, which generates 2.6 mmol·h-1·g-1 under visible light irradiation. Meanwhile, the CdS-3 sample shows superior HER performance during recycling tests and exhibits relatively steady photocatalytic performance in the 10 h experiment. Expanded absorption of visible light, decreased recombination possibility for photo-induced carriers and a more negative conduction band position are mainly responsible for the enhanced photocatalytic hydrogen evolution performance. Photo-induced electrons will be motivated to the conduction band of CdS under the irradiation of visible light and will further transfer to Cd(OH)2 to react with H+ to produce H2. The in situ-formed Cd(OH)2 could effectively facilitate the electron transfer and reduce the recombination possibility of photo-generated electron-hole pairs.

Well-designed protein amyloid nanofibrils composites as versatile and sustainable materials for aquatic environment remediation: A review.

Amyloid nanofibrils (ANFs) are supramolecular polymers originally classified as pathological markers in various human degenerative diseases. However, in recent years, ANFs have garnered greater interest and are regarded as nature-based sustainable biomaterials in environmental science, material engineering, and nanotechnology. On a laboratory scale, ANFs can be produced from food proteins via protein unfolding, misfolding, and hydrolysis. Furthermore, ANFs have specific structural characteristics such as a high aspect ratio, good rigidity, chemical stability, and a controllable sequence. These properties make them a promising functional material in water decontamination research. As a result, the fabrication and application of ANFs and their composites in water purification have recently gained considerable attention. Despite the large amount of literature in this field, there is a lack of systematic review to assess the gap in using ANFs and their composites to remove contaminants from water. This review discusses significant advancements in design techniques as well as the physicochemical properties of ANFs-based composites. We also emphasize the current progress in using ANFs-based composites to remove inorganic, organic, and biological contaminants. The interaction mechanisms between ANFs-based composites and contaminants are also highlighted. Finally, we illustrate the challenges and opportunities associated with the future preparation and application of ANFs-based composites. We anticipate that this review will shed new light on the future design and use of ANFs-based composites.

Cadmium removal by FeOOH nanoparticles accommodated in biochar: Effect of the negatively charged functional groups in host.

Metallic oxide nanoparticles (NPs) anchored in biochar provide a promising measure forward into the scaled-up application of these NPs in water treatment, and reducing the size of the dwelled NPs is expected to boost the adsorption performance of biochar-based composites because of the size and surface effect. Nevertheless, it is still of great challenge to regulate the size of the impregnated NPs due to their intrinsic self-agglomeration caused by high surface energy. In this study, we fabricated the charged biochar (C-BC) bearing high-density negatively charged groups (i.e., carboxyl and hydroxyl groups) via HNO3 oxidization to load the model metal oxide FeOOH NPs. The average sizes of anchored FeOOH NPs were ultrasmall, ranging from 19.9 ± 1.5 to 3.1 ± 0.5 nm, and decreased with the increased amount of carboxyl and hydroxyl groups in C-BC. Whether in batch adsorption or fixed-bed column setting, adsorption of Cd(II) onto the as-made composites was greatly enhanced by carboxyl and hydroxyl groups in carrier. The normalized adsorption capacities of Cd(II) by ferric mass of the loaded FeOOH were 499.9-724.9 mg/g-Fe, approximately 18.6-27.1 and 2.51-3.64 folds over the bulky FeOOH and FeOOH-impregnated biochar. Our study results should provide a significant reference on how to acquire highly efficient biochar-based composites for water decontamination.

Development of an acidized biochar-supported hydrated Fe(III) oxides for highly efficient cadmium and copper sequestration from water.

Biochar-supported metallic oxides are attractive adsorbents for heavy metal cleanup, but the adsorption performance is still unsatisfactory as a result of the self-aggregation of the incorporated metallic oxides. A new hybrid nano-material was prepared through impregnating hydrated ferric oxide (HFO) nanoparticles within biochar bearing high-density charged oxygen-containing groups (e.g., carboxyl and hydroxyl groups) (ABC) derived from HNO3 treatment. The as-made adsorbent, denoted as HFO-ABC, possesses highly dispersed HFO nanoparticles with typical size lower than 20 nm, and exhibits greater sorption capacity for Cd(II) and Cu(II) than the pristine biochar-supported HFO. It also shows great sorption preference toward Cd(II) and Cu(II) in co-presence of high levels of Ca2+, Mg2+ and humic acid (HA). Such prominent performance is put down to the high-density charged functional groups on the host ABC, which not only promote the dispersion of the immobilized HFO nanoparticles but also generate the potential Donnan membrane effect, i.e., the pre-concentration and permeation of target metals prior to their preferable adsorption by nano-HFO. The predicted effective coefficients of intra-particle diffusion for Cu(II) and Cd(II) are 3.83 × 10-9 and 4.33 × 10-9 cm2/s, respectively. HFO-ABC exhibits excellent performance for fixed-bed column application, and yields 513 and 990 BV effluents for Cd(II) and Cu(II) to achieve their discharge standards, respectively. The spent HFO-ABC could be in situ regenerated using binary HCl-CaCl2 solution with desorption efficiency higher than 95%. All results manifest that increasing charged functional groups via HNO3 treatment is an effective measure for boosting sorption performance of biochar-based nanocomposites.

Enhanced Removal of Heavy Metals from Water by Hydrous Ferric Oxide-Modified Biochar.

Biochar has become an attractive adsorbent for heavy metal removal, but its application potential is very limited because of the relatively low adsorption capacity and poor selectivity. In the present study, we decorated the biochar (BC) by impregnating hydrous ferric oxide (HFO) within the pore of biochar and consequently obtained a new hybrid adsorbent denoted as HFO-BC. The results show HFO-BC exhibited excellent performance to two representative heavy metals, i.e., Cd(II) and Cu(II), with maximal experimental sorption capacities of 29.9 mg/g for Cd(II) and 34.1 mg/g for Cu(II). HFO-BC showed satisfactory anti-interference ability for Cd(II) and Cu(II) removal in the presence of high levels of Ca(II) and Mg(II) owing to the specific inner-sphere complexation between the immobilized HFO and Cd(II) and Cu(II), which was probed by XPS analysis. Cd(II) and Cu(II) removal onto HFO-BC experienced two distinct stages prior to be adsorbed, i.e., migration from solution to the outside surface of adsorbent and pore diffusion and approached equilibrium within 100 min. In the laboratory-scale small column adsorption experiment, HFO-BC can generate ∼129 and 300 BV effluents for Cd(II) and Cu(II), equivalent to 774- and 1854-fold of its own weight, to meet their treatment standards. Moreover, the exhausted HFO-BC can be effectively regenerated using HCl-CaCl2 binary solution with a desorption rate more than 95%. All results validate that impregnating HFO inside the pores of BC is a promising approach to promote the practical applicability of BC for removing heavy metals from the polluted water.

Discovery of Coumarin as Microtubule Affinity-Regulating Kinase 4 Inhibitor That Sensitize Hepatocellular Carcinoma to Paclitaxel.

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers worldwide. Nowadays, pharmacological therapy for HCC is in urgent needs. Paclitaxel is an effective drug against diverse solid tumors, but commonly resisted in HCC patients. We recently have disclosed that microtubule affinity-regulating kinase 4 (MARK4) increases the microtubule dynamics and confers paclitaxel resistance in HCC, suggesting MARK4 as an attractive target to overcome paclitaxel resistance. Herein, we synthesized and identified coumarin derivatives 50 as a novel MARK4 inhibitor. Biological evaluation indicated compound 50 directly interacted with MARK4 and inhibited its activity in vitro, suppressed cell viability and induced apoptosis of HCC cells in a MARK4-dependent manner. Importantly, compound 50 significantly increased the drug response of paclitaxel treatment to HCC cells, providing a promise strategy to HCC treatment and broadening the application of paclitaxel in cancer therapy.

Enhanced lead and cadmium removal using biochar-supported hydrated manganese oxide (HMO) nanoparticles: Behavior and mechanism.

Hydrated manganese oxide (HMO) nanoparticles were impregnated into a peanut shell-derived biochar (BC) to obtain a remarkable nanocomposite adsorbent, HMO-BC, which overcomes the technical barriers of singly applying either HMO or BC in practical heavy metal-containing wastewater treatment. HMO-BC can effectively sequestrate Pb(II) and Cd(II) in a wide pH range of 3-7 and exhibited more preferable sorption than bare BC in the presence of high-level competing cations. BC also significantly lowered the Mn leaching at acidic pH. Fixed-bed column adsorption tests showed that the effective treatment volume of HMO-BC for a simulated Pb(II)- or Cd(II)-laden wastewater is about 4-6 times higher than that of the BC host. In addition, HMO-BC was effective in removing Pb(II) from a real Pb-containing electroplating wastewater to discharge limit (0.2mgL-1) with treatable volume of 525BV, much higher than that of the bare BC (60BV). More importantly, the saturated HMO-BC can be thoroughly regenerated for repeated uses without any observable capacity loss. Such attractive results of HMO-BC were attributed to the complementary effect of its two components. The embedded HMO nanoparticles provide preferable capture of target cations through specific inner-sphere complexation, as illustrated by XPS spectra of Pb 4f7/2 and O1s, while the non-diffusive negatively charged oxygen-containing groups bound to BC facilitate the pre-enrichment and permeation of Pb(II) and Cd(II) cations into the pore channels prior to their preferable sorption through the Donnan membrane effect.

[MgO-Biochar for the Adsorption of Phosphate in Water].

A novel composite material MgO-biochar (MgO-BC) with the peanut shells as the precursors was successfully fabricated by loading magnesium oxide (MgO) on the surface of biochar (BC) at high temperature and in oxygen-limited atmosphere. The adsorption characteristics of the resultant adsorbent toward phosphate from aqueous solution were investigated by evaluating the influences of pH, contact time and coexisting ions. The results showed that the best phosphate adsorption onto MgO-BC happened in the pH range of 7-9, and strong acidic or basic media was unfavorable to the phosphate adsorption. Phosphate adsorption process could reach equilibrium within 540 min, and the kinetics curve could be well fitted by both pseudo-first and pseudo-second models. The related coefficients were 97.3% and 99.0%. MgO-BC exhibited highly selective capacity toward phosphate in the presence of competing Cl-, HCO3- and NO3- at 10 times higher concentration than the phosphate concentration. In addition, phosphate adsorption onto MgO-BC could be described satisfactorily by Langmuir model with a fitting coefficient of higher than 99%, and the maximal adsorption capacity calculated by Langmuir equation was 138.07 mg·g-1. The adsorption capacity of phosphate by MgO-BC was much higher than the unmodified BC and other biochar-based sorbents. Furthermore, the composite material after the adsorption of phosphate could also be used as a fertilizer into the soil. It achieved the reuse of the discarded phosphate. All the results validated that MgO-BC has a wide application prospect for the phosphate cleanup from the actual wastewater.

Phosphate removal by lead-exhausted bioadsorbents simultaneously achieving lead stabilization.

Low-cost adsorbents have been continuously developed for heavy metal removal, but little information is available concerning the follow-up treatment of the toxic metal-laden adsorbents. In this study, an optional strategy was provided for the further treatment of heavy metal-impregnated low-cost adsorbents through employing them for phosphate retention. The enhancement of phosphate adsorption by the sorbed lead was first validated using several types of raw or modified waste biomass. Tea waste-supported hydrated manganese dioxide (HMO-TW) with the highest Pb sorption capability was then chosen to systematically evaluate phosphate retention. Phosphate adsorption onto lead-laden HMO-TW (HMO-TW(Pb)) was pH-insensitive with only slight decline at pH > 8.5, and was barely affected by competing anions owing to the specific surface precipitation mechanism. Moreover, no signs of lead leakage from HMO-TW(Pb) were observed during phosphate adsorption at a wide pH range (4.2-11.3) and high ion strength (0-250 mg L-1 NaNO3). The lead on HMO-TW(Pb) was greatly stabilized through phosphate retention, which also reduced the environmental risks of their following treatment such as solidification and landfill. Additionally, the phosphate adsorption onto HMO-TW(Pb) was quick (with equilibrium time <60 min) and barely affected by temperature. Fixed-bed column test further suggested that HMO-TW(Pb) has practical applicability in efficient removal of phosphate from water.

Rapid and highly selective removal of lead from water using graphene oxide-hydrated manganese oxide nanocomposites.

To overcome the limits of graphene oxide (GO) as a novel sorbent for heavy metal removal (e.g., low sorption selectivity and difficulty in solid-liquid separation), a nanocomposite (HMO@GO) with excellent settling ability (<2min) was fabricated through in situ growing nanosized hydrated manganese oxide (HMO) (10.8±4.1nm) on GO. As a graphene-based adsorbent, HMO@GO exhibited fast sorption kinetics (<20min). Meanwhile, the introduced HMO endowed HMO@GO with outstanding sorption selectivity and capacity toward Pb(II) (>500mgg(-1)) in the presence of high-level competing Ca(II). Cyclic sorption batches showed that 1kg HMO@GO can treat at least 22m(3) Pb(II)-laden synthetic industrial drainage (5mgL(-1) Pb(II)) and 40m(3) drinking water (0.5mgL(-1) Pb(II)) to their corresponding limits (0.1mgL(-1) for wastewater and 10µgL(-1) for drinking water) enforced in China. Additionally, the exhausted HMO@GO can be effectively regenerated using 0.3 M HCl for repeated uses. The eminent performance of HMO@GO was attributed to its specific structure, that is, the abundant oxygen-containing groups on GO mediated the growth of highly dispersed HMO that preferably sequestrated Pb(II) through specific interaction, and the host GO offered the preconcentration of Pb(II) for enhanced sequestration through the Donnan membrane effect.

[Sorption characteristics of tea waste modified by hydrated ferric oxide toward Pb(II) in water].

Hydrated ferric oxide was successfully impregnated onto tea waste by precipitation to obtain a new sorbent named HFO-TW, the adsorption characteristics of which toward Pb(II) in aqueous solution was investigated by evaluating the effects of pH value, contact time, coexisting ion, temperature, and initial concentration of Pb(II). The Pb(II) sorption onto HFO-TW was pH- dependent, and the higher pH value was more helpful for Pb(II) adsorption onto HFO-TW in the pH range of 2.5-7. Lead sorption speed was quick and could reach equilibrium within 100 min, and the kinetics curve could be fitted well by both pseudo-first and pseudo-second models. The related coefficient was 98.8%. HFO-TW exhibited highly selective lead retention and the adsorption capacity of Pb(II) onto HFO-TW was declined by only 12.1 mg · g(-1) and 8.1 mg · g(-1) in the presence of competing Ca(II), Mg(II) at 50 times of the target ion. In addition, Pb(II) sorption onto HFO-TW could be described satisfactorily by Langmuir model, and the maximal sorption capacity calculated by Langmuir equation was 89.43 mg · g(-1), which was much higher than the unmodified tea waste and other bio-sorbents. All the results validated that HFO-TW was a promising sorbent for removal of lead from waters.

Use of hydrous manganese dioxide as a potential sorbent for selective removal of lead, cadmium, and zinc ions from water.

Selective removal of three toxic metal ions, Pb(II), Cd(II), and Zn(II), from aqueous solution by amorphous hydrous manganese dioxide (HMO) was evaluated. Two polymeric exchangers, a polystyrene-sulfonic cation exchanger, D-001, and an iminodiacetic acid chelating exchanger, Amberlite IRC 748, were involved for comparison. Hydrogen ion release is accompanied by metal uptake onto HMO, implying that metal sorption could be generally represented by an ion-exchange process. As compared to both exchangers, HMO exhibits preferable sorption toward the toxic metals in the presence of Ca(II) ions at greater levels. FT-IR of the HMO samples laden with different metals indicate that Ca(II) uptake onto HMO is mainly driven by outer-sphere complexation, while that of three toxic metals might be related to inner-sphere complex formation. In addition, uptake of heavy metals onto HMO approaches equilibrium quickly and the exhausted HMO particles can be regenerated readily for repeated use by HCl solution. The results reported strongly display the potential of HMO as an economic and selective sorbent for removal of toxic metals from contaminated waters.