AC/off-grid photovoltaic powered open-source ball mill

Ball milling is used for comminution by rotating a drum to grind materials using balls with specific diameters. Ball milling advantages include the potential for high capacity, predicted fineness in a specific amount of time, reliability, safety, and simplicity, but has disadvantages of high weight, energy consumption and costs, which limit accessibility. To overcome these limitations this study applies the free and open source hardware approach coupled to distributed digital manufacturing to fabricate a ball mill with a simple, customizable design that can be used in a wide range of scientific applications and circumstances including those without access to reliable grid electricity. The highly-customizable design reduces the cost to <US$130 for an AC powered version and <US$315 for a switchable power that enables off-grid operation with a solar module and battery. Using a solar photovoltaic energy source not only improves the power reliability, but also makes it easier to move the ball mill for use in field environments. The open source ball mill is capable of reducing silicon particle sizes from the millimeter scale down to the nanometer scale.

Mitigating soil salinity stress with titanium gypsum and biochar composite materials: Improvement effects and mechanism

Titanium gypsum and biochar are considered effective amendments for mitigating soil salinity stress. However, the knowledge is inadequate regarding their efficiency and application as an improvement. In this study, TG-B composite was prepared by using industrial by-products titanium gypsum and biochar as raw materials and then modified by ball milling method, to characterize its microscopic characteristics and explore the improvement effect on saline-alkali soil and plant growth. Besides, we explored the mechanism of TG-B in improving saline-alkali soil and the dynamic balance of the solution reaction process. Our results showed that the CaSO₄·2H₂O particles in TG-B were finer, dispersed evenly, and contacted fully with soil gelatinous particles, which was more conducive to the improvement of saline-alkali soil. The results of TG-B with different ball milling ratios and different materials dosages indicated that the application rate of TG-B was 5%, and the optimum ratio of TG-B was TG: B (mass ratio) = 10:1, with the best soil improvement effect. The pot experiment proved that the indicators of indicating soil salinity such as pH, EC, SAR, and soluble Na⁺ decreased by 20.74%, 77.24%, 68.77%, and 44.70%, respectively, thus playing a good role in improving saline-alkali soil. In addition, pot experiments demonstrated that compared with the control group, the soil porosity and soil moisture content in the TG-B group increased by 15.95% and 38.71%, respectively, and further improve the structure and diversity of soil bacterial community when compared with titanium gypsum and biochar alone. Finally, the application of TG-B promoted the germination and growth of rice significantly through the synergistic effects of composite material components. These results all suggested that the application of TG-B was an effective strategy to improve soil salinity and promote plant growth. Therefore, it might provide new insights into the utilization of solid waste resources to improve saline-alkali lands.

Combined removal of SO3 and HCl by modified Ca(OH)2 from coal-fired flue gas

As treatments for mainstream pollutants in coal-fired power plants have been established, the control of non-conventional pollutants, such as SO₃ and HCl, is gradually gaining attention. In this study, combined SO₃ and HCl removal is proposed based on SO₃ removal by absorber injection. However, it is challenging to selectively absorb SO₃ and HCl from SO₂-rich atmospheres. Therefore, Ca(OH)₂ was modified via ball milling and doping with CuO for the combined removal of SO₃ and HCl. The results showed that ball milling reduced the particle and grain sizes of Ca(OH)₂, which increased the active sites of Ca(OH)₂ and prolonged reaction time. After modification by ball milling, SO₃ absorption per mg of Ca(OH)₂ increased by 40 %. However, HCl removal efficiency was difficult to improve by modifying Ca(OH)₂ using only ball milling under SO₃ and SO₂ atmospheres. Therefore, the dechlorination capacity of Ca(OH)₂ was improved by adding ions during the ball milling process. Doping of Ca(OH)₂ with Cu²⁺ changed its crystal structure, weakened the diffusion resistance of HCl, and improved Ca(OH)₂ utilization. Additionally, it increased the energy of Ca(OH)₂ to adsorb HCl.

Preparation of Seaweed Nanopowder Particles Using Planetary Ball Milling and Their Effects on Some Secondary Metabolites in Date Palm (Phoenix dactylifera L.) Seedlings

Due to their distinctive physicochemical characteristics, nanoparticles have recently emerged as pioneering materials in agricultural research. In this work, nanopowders (NP) of seaweed (Turbinaria triquetra) were prepared using the planetary ball milling procedure. The prepared nanopowders from marine seaweed were characterized by particle size, zeta potential, UV-vis spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). When the seaweed nanopowder of Turbinaria triquetra was subjected to FT-IR analysis, it revealed the presence of different functional groups, including alkane, carboxylic acids, alcohol, alkenes and aromatics. Moreover, the methanol extract was used to identify the polyphenolic components in seaweed (NP) using high performance liquid chromatography (HPLC) and the extract revealed the presence of a number of important compounds such as daidzein and quercetin. Moreover, the pot experiment was carried out in order to evaluate the effects of prepared seaweed (NP) as an enhancer for the growth of date palm (Phoenix dactylifera L.). The date palm seedlings received four NP doses, bi-distilled water was applied as the control and doses of 25, 50 or 100 mg L^-1 of seaweed liquid NP were used (referred to as T1, T2, T3 and T4, respectively). Foliar application of liquid NP was applied two times per week within a period of 30 days. Leaf area, number of branches, dry weight, chlorophylls, total soluble sugars and some other secondary metabolites were determined. Our results indicated that the foliar application of liquid NP at T3 enhanced the growth parameters of the date palm seedlings. Additionally, liquid NP at T3 and T4 significantly increased the photosynthetic pigments. The total phenolic, flavonoid and antioxidant activities were stimulated by NP foliar application. Moreover, the data showed that the T3 and T4 doses enhanced the activity of the antioxidant enzymes (CAT, POX or PPO) compared to other treatments. Therefore, the preparation of seaweed NP using the planetary ball milling method could produce an eco-friendly and cost- effective material for sustainable agriculture and could be an interesting way to create a nanofertilizer that mitigates plant growth.

Encapsulation of Lactobacillus acidophilus in solid lipid microparticles via cryomilling

We herein delved into the microencapsulation of Lactobacillus acidophilus (LA) into solid lipid microparticles (SLMs) via the cryomilling technique. For this aim, a frozen lipid mixture containing LA was pulverized at different times (7, 14, 21, 28, and 35 min) using a cryogenic mixer mill to produce probiotic-loaded SLMs. The impacts of different cryomilling durations on the SLMs properties (morphology, particle size, water activity, polymorphism, crystallinity, and thermal behavior) and the viability of LA were evaluated. Microencapsulation improved the viability of LA in simulated gastrointestinal fluids, heat stress, and different concentrations of salt and sucrose. SLMs also were suitable to be incorporated into foods. However, once the cryomilling time was prolonged, the viability of encapsulated LA declined, and particle size grew. The cryomilling technique showed great potential as an alternative approach for encapsulation due to the lack of solvent, short processing time, and simplicity.

Synthesis of mesoporous antimicrobial herbal nanomaterial-carrier for silver nanoparticles and antimicrobial sensing

Herbal nanoparticles (HNPs) were introduced as a novel generation of antimicrobial nanoparticles. But in the battle against superbugs we need nanostructures with boosted antimicrobial potency. So in the current experiment, for the first time a green approach was developed for the silver functionalization of HNPs which were fabricated from an antimicrobial herb Thymus vulgaris. Silver functionalized HNPs (AgHNPs) were found to be mesoporous and were further fortified with antimicrobial compounds. The resulted structures were re-tested against MRSA and P. aeruginosa as superbugs. It was found that silver functionalization can provide eight-fold increase in the antimicrobial potency of HNPs. Moreover, MIC was reduced from 20 mg/mL to 2.5 mg/mL. Another eight-fold reduction in the MIC (0.3 mg/mL) was achieved by fortification with antimicrobial compounds. So, the antimicrobial potency of HNPs was successfully increase approximately up to 64-folds. Obtained results illustrated that silver functionalization and fortification with antimicrobial compounds can be considered as effective approaches to achieve HNPs with boosted antimicrobial potency. These nanostructures have the potency to be loaded with other antimicrobial compound such as antibiotics toward synergistic effects of AgNPs and antibiotics. Resulted nanostructures can be employed in the formulation of powerful topical and surface disinfectants against superbugs. Also, these particles can be considered as a next generation of boosted antimicrobial nanostructures.

Activation of peroxydisulfate by ball-milled α-FeOOH/biochar composite for phenol removal: Component contribution and internal mechanisms

Persulfate-based advanced oxidation process is considered as a promising technology for the degradation of phenol, where efficient, cost effective, and green methods with high peroxydisulfate (PS) activation capacity is of increasing demand. In this work, an in-situ liquid phase precipitation combined with ball milling method was applied for the synthesized of α-FeOOH/biochar, as be the PS activator for phenol degradation. Results showed that the ball-milled α-FeOOH and red pine wood biochar prepared at 700 °C (BM-α-FeOOH/PBC700) exhibited the highest catalytic property with PS for phenol oxidation (a phenol removal rate of 100%), compared with the BM-α-FeOOH (16.0%) and BMPBC700 (66.3%). The presence of intermediate products such as hydroquinone and catechol, and total organic carbon (TOC) removal rate (88.9%) proved the oxidation of phenol in the BM-α-FeOOH/PBC700+PS system. The characterization results showed that the functional groups (e.g., CO, C-O, Fe-O, and Si-O), the dissolved organic matter (DOM) in biochar, the loading of Fe element, and higher degree of graphitization and defect structures, contributed to the activation of PS to form free radicals (i.e., SO₄^·-, ·OH, ·O₂^-, and h_VB⁺) for phenol oxidation, of which, SO₄·^- and ·OH account for 72.1% of the phenol removal rate. The specific contribution to the PS activation for phenol oxidation by each part of the materials was calculated based on the "whole to part" experiment. The contribution of DOM, acid-soluble substance, and carbon matrix and basal part in BM-α-FeOOH/PBC700 were 6.0%, 40.9%, and 53.1%, respectively. The reusability experiments of BM-α-FeOOH/PBC700 demonstrated that the composite was relatively stable after four cycles of reuse. Among three co-existing anions (NO₃^-, Cl^-, and HCO₃^-), HCO₃^- played the most significant inhibition effects on phenol removal through reducing the phenol removal rate from 89.6% to 77.9%. This work provides guidance for the design of high active and stable carbon materials that activate PS to remove phenol.

Effects of Temperature, Solution pH, and Ball-Milling Modification on the Adsorption of Non-steroidal Anti-inflammatory Drugs onto Biochar

This study explored the adsorption of representative non-steroidal anti-inflammatory drugs (NSAIDs), acetaminophen (AP), ibuprofen (IB), and salicylic acid (SA) by biochars. The sorption kinetics were fitted with six commonly used kinetic models, and the isotherm data was well described by both Langmuir and Freundlich models. Biochars of longer pyrolysis time showed better performance with the Langmuir maximum sorption capacities for AP, IB, and SA of 196 mg/g, 132 mg/g, and 48.8 mg/g, respectively. Variation in temperature hardly affected the adsorption performances, while the influence of pH exhibited pronounced dependency on physicochemical properties of both NSAIDs and biochars. Eighteen ball-milled (BM) biochars were then produced under different ball-milling conditions and examined for NSAIDs removal. Compared with unmilled biochars, BM-biochars produced under optimum conditions showed higher removal efficiencies. Electrostatic interaction and pore width of biochars greatly affected the NSAIDs adsorption onto biochars.

Preparation of C-MOx nanocomposite for efficient adsorption of heavy metal ions via mechanochemical reaction of CaC2 and transitional metal oxides

Three nanocomposites of carbon and MnOx (C-Mns) were prepared via mechanochemical reaction of CaC₂ with excessive MnO₂ in a planetary ball mill. Their structure and composition were analyzed by XPS, Raman, FT-IR, XRD, N₂ adsorption-desorption, SEM and TEM, respectively, and their adsorption performance for heavy metal ions was studied. In addition, a series of nanocomposites of carbon and transition metal oxides (C-MOx) were prepared by ball milling CaC₂ with excessive TiO₂, V₂O₅, Fe₂O₃, CuO, MoO₃, Co₂O₃, and CrO₃, respectively, and their adsorptivity was evaluated. C-Mn₁ is a micro-mesoporous sorbent with rich MnOx, alkynyl and oxygenated groups, and moderate specific area (∼180 m² g^-1), showing excellent Pb²⁺ adsorption with its saturated adsorptivity being 404.4 mg-Pb g^-1. Further, it is also effective for other heavy metals (Hg²⁺, Cd²⁺, Cr³⁺, Zn²⁺ and Cu²⁺). Some C-MOx show even better adsorptivity for Pb²⁺ and Hg²⁺, being superior to most of the advanced carbon-based sorbents. We reported herein a facile method for preparing a new kind of C-MOx nanocomposites for the efficient adsorption of heavy metal ions from wastewater.

Solvent-free synthesis of magnetic biochar and activated carbon through ball-mill extrusion with Fe3O4 nanoparticles for enhancing adsorption of methylene blue

Magnetic carbonaceous adsorbents were synthesized by ball-milling biochar (BC) or activated carbon (AC) with Fe₃O₄ nanoparticles, and their capacities to sorb methylene blue (MB) from water were evaluated and compared. Ball milling with magnetite not only improved the surface properties of the carbonaceous adsorbents, especially BC, but also introduced magnetic properties through mechanical extrusion. Furthermore, ball-mill extrusion increased the MB adsorption capacity of BC at all pH values by 14-fold, on average, but BC ball milled with magnetite had even greater MB adsorption capacity (27-fold, greater, on average). While ball milling of AC also improved its MB adsorption capacity (by almost 3-fold, on average), ball milling with magnetite did not further improve its MB adsorption capacity. All the magnetic adsorbents showed fast MB adsorption kinetics, reaching equilibrium within about 8 h. The Langmuir maximum MB adsorption capacity of the magnetic ball-milled BC (MBM-BC) was the highest (500.5 mg/g) among all the samples including the ones derived from AC. After five adsorption-desorption cycles, MBM-BC maintained about 80% MB removal capacity. The high MB adsorption capacity of MBM-BC was attributed to its increased surface area, opened pore structure, functional groups and aromatic CC bonds, which promoted π-π and electrostatic interactions. Findings from this study indicate that the magnetic ball-milled BC is a promising adsorbent due to its environmentally friendly synthesis, high efficiency, low cost, and convenience in operation.

Ball milled biochar effectively removes sulfamethoxazole and sulfapyridine antibiotics from water and wastewater

Release of antibiotics into the environment, which often occurs downstream of wastewater treatment plants, poses a human health threat due to the potential development of bacterial antibiotic resistance. In this study, laboratory experiments were conducted to evaluate the performance of ball milled biochar on the removal of two sulfonamide antibiotics, sulfamethoxazole (SMX) and sulfapyridine (SPY) from water and wastewater. Aqueous batch sorption experiment using both pristine and ball milled biochar derived from bagasse (BG), bamboo (BB) and hickory chips (HC), made at three pyrolysis temperatures (300, 450, 600 °C), showed that ball milling greatly enhanced the SMX and SPY adsorption. The 450 °C ball milled HC biochar and BB biochar exhibited the best removal efficiency for SMX (83.3%) and SPY (89.6%), respectively. A range of functional groups were produced by ball milling, leading to the conclusion that the adsorption of sulfonamides on the biochars was controlled by multiple mechanisms including hydrophobic interaction, π-π interaction, hydrogen bonding, and electrostatic interaction. Due to the importance of electrostatic interaction, SMX and SPY adsorption was pH dependent. In laboratory water solutions, the Langmuir maximum adsorption capacities of SMX and SPY reached 100.3 mg/g and 57.9 mg/g, respectively. When tested in real wastewater solution, the 450 °C ball milled biochar still performed well, especially in the removal of SPY. The maximum adsorption capacities of SMX and SPY in wastewater were 25.7 mg/g and 58.6 mg/g, respectively. Thus, ball milled biochar has great potential for SMX and SPY removal from aqueous solutions including wastewater.

Thiol-modified biochar synthesized by a facile ball-milling method for enhanced sorption of inorganic Hg2+ and organic CH3Hg. J Hazard Mater 2020;384:121357. [PMID: 31630859 DOI: 10.1016/j.jhazmat.2019.121357]

Modification of thiol on biochar often demands complex synthetic procedures and chemicals. In this work, a simple and environment friendly thiol-modified biochar (BMS-biochar) was successfully synthesized by ball milling pristine biochar with 3-mercaptopropyltrimethoxysilane (3-MPTS). The resultant BMS-biochar was characterized and tested for aqueous inorganic Hg²⁺ and organic CH₃Hg⁺ removal. Characterization results showed that 3-MPTS was loaded on the surface of biochar through oxygen-containing functional groups (i.e., OH and CO) and π-π bond. Ball milling method improved the properties of BMS-biochar, namely, more efficient SH load, a larger surface area, more functional groups, more negatively charged surface, which resulted in higher removal efficiency of Hg²⁺ and CH₃Hg⁺ (320.1 mg/g for Hg²⁺ and 104.9 mg/g for CH₃Hg⁺) compared to the pristine biochar (105.7 mg/g for Hg²⁺ and 8.21 mg/g for CH₃Hg⁺) and thiol-modified biochar through chemical impregnation (CIS-biochar) (175.6 mg/g for Hg²⁺ and 58.0 mg/g for CH₃Hg⁺). Ball milling increased the sorption capacities of Hg²⁺ and CH₃Hg⁺ through surface adsorption, electrostatic attraction, ligand exchange, and surface complexation. Modeling results suggested that the surface diffusion was the rate-limiting adsorption step for BMS-biochar. This work gave prominence to the potential of ball milling for the preparation of thiol-modified biochar to remove mercury especially organic CH₃Hg⁺ by adsorption.

Investigation of flow dynamics of porous clinkers in a ball mill using technitium-99m as a radiotracer

A radiotracer investigation was carried out in a ball mill of a cement plant in Kenya. Residence time distribution (RTD) of raw feed to the mill was measured using Technetium-99m adsorbed on the clinkers as a radiotracer. From the measured RTDs, solid holdup and mean residence times (MRTs) in the ball mill and associated separator were determined. The measured RTDs were modelled using axial dispersion model (ADM) and tank-in-series model both connected with a plug flow component in series. The results of the modelling indicated significant degree of backmixing within the ball mill and no axial mixing in the separator.

Synthesis and Characterization of Natural Nano-hydroxyapatite Derived from Turkey Femur-Bone Waste

Hydroxyapatite (HAp) is a bioactive and vital material which has found many applications in the biomedical and clinical fields. This bio-ceramic powder can be synthesized via different bio-waste materials. In this study, the production of natural nanohydroxyapatite was produced through calcination of untreated turkey femur-bone waste powder at 850 °C followed by ball milling the powder. The obtained powder was characterized using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis. The morphology, size, and elemental composition of obtained turkey hydroxyapatite (THA) particles were investigated by scanning electron microcopy (SEM), transmission electron microcopy (TEM), and energy dispersive spectroscopy (EDS) analysis, in which the average particle size of ball milled THA was found to be about 85 nm with a Ca/P ratio of 1.63. The powder was then cold pressed and later sintered at 850, 950, 1050, and 1150 °C to evaluate its mechanical properties in terms of compressive strength and hardness. The results revealed that the strength and hardness of the samples increased by increasing the sintering temperature up to 1150 °C. Finally, the maximum values of hardness and compressive strength of the sintered THA were obtained at 1150 °C (37.44 MPa and 3.2 GPa, respectively).

Comparative study of calcium alginate, ball-milled biochar, and their composites on aqueous methylene blue adsorption

In this work, a novel composite, ball-milled biochar (BMB) encapsulated in calcium-alginate (CA) beads (CA-BMB), was synthesized as an alternative adsorbent for the removal of methylene blue (MB) from an aqueous solution. Sorption performance was compared among CA, BMB, and CA-BMB composite with batch adsorption experiments. With 25% BMB and 75% alginate, the new composite resembled CA in MB adsorption. With an initial MB concentration of 50 mg L^-1, kinetics studies showed that 74% MB removal by CA-BMB was achieved within 8 h, followed by slow kinetics reaching 91% removal in 16 h. The adsorption kinetics was well explained by the Ritchie's kinetic model, indicative of energetically heterogeneous solid surface of the composite. Adsorption isotherms of BMB, CA, and CA-BMB can all be fitted with the Langmuir models; the adsorption capacity of CA-BMB (1210.7 mg g^-1) was close to that of CA (1282.2 mg g^-1) and much higher than that of BMB alone (184.1 mg g^-1). The outstanding adsorption performance suggested that CA-BMB can serve as a low-cost and eco-friendly adsorbent for MB removal from an aqueous solution.

Ball-milled biochar for galaxolide removal: Sorption performance and governing mechanisms

The environmental risk of galaxolide (HHCB) spurs the need to develop efficient and economical removal technology. Although sorption is one of the best removal approaches, studies on sorption of HHCB by biochar were limited. With the purpose of combining the advantages of ball-milling and sorption technologies, six ball-milled biochars (BM-biochars) varied with biomasses and pyrolysis temperature were produced, characterized, and tested for HHCB removal from aqueous solution. At an initial HHCB concentration of 2 mg L^-1, the unmilled and BM-biochars adsorbed 330-746 and 609-2098 mg kg^-1 of HHCB, respectively. The increase in sorption capacities (about 3-fold increase) was mainly ascribed to the increase in BM-biochar's external and internal surface area, pore volume and pore size, and the exposure of the graphitic structure. The removal of HHCB by the BM-biochars increased with increasing pyrolysis temperature. For lower temperature biochar (300 °C wheat straw biochar, WS300), hydrophobic partitioning played a major role in HHCB sorption onto unmilled biochar (log K_oc/log K_ow value of WS300 was 0.772 at a C_e of 1 mg L^-1). Ball milling reduced the hydrophobicity of 300 °C biochar, which diminished the HHCB sorption. However, increased surface area, pore volume, pore size, and graphitic structure provided additional sorption sites, resulting in enhanced HHCB uptake (log K_oc/log K_ow value of BMWS300 was 1.23 at a C_e of 1 mg L^-1). For higher temperature biochars (500 and 700 °C), ball milling mainly enhanced HHCB sorption onto high temperature biochars via surface adsorption, π-π interaction, and pore filling. For WS500, 77.9% of HHCB removal was due to surface adsorption. Ball milling increased this percentage to 96.7% for BMWS500. This work highlighted the potential of ball milling as an excellent engineering method to improve biochar's sorption properties.

Qualitative and quantitative correlation of physicochemical characteristics and lead sorption behaviors of crop residue-derived chars

This study investigated the key physicochemical characteristics of char that control its ability to absorb Pb²⁺. Three type of crop residue-derived chars and their ball milled powder were characterized using multiple approaches. The Pb²⁺ sorption mechanisms of biochar were caused mainly by coprecipitation reactions, which were governed by ionic minerals on chars instead of mineral crystallization (e.g., SiO₂ and Al₂O₃), while coprecipitation reactions and π electronic interaction were the dominant mechanisms of activated carbon. Pearson analysis showed that adsorption quantity (Q) highly correlated with the cation exchange capacity (CEC) (P < 0.01)/oxygen functional groups (OFGs) (P < 0.05) and Q closely correlated with coprecipitation amount (P < 0.01)/complexation amount (P < 0.01). Linear regression equations of sorption amount and CEC (R² ＞ 0.8)/OFGs (R² ＞ 0.7) were established. CEC and OFGs of chars are the key factors controlled Pb²⁺ sorption. These results may promote the development of low-cost, engineered biochar with superior sorption qualities for environmental remediation.

Effects of ball milling on the physicochemical and sorptive properties of biochar: Experimental observations and governing mechanisms

With the goal of combining the advantages of ball-milling and biochar technologies, a variety of ball-milled biochars (BM-biochars) were synthesized, characterized, and tested for nickel (Ni(II)) removal from aqueous solution. Ball milling increased only the external surface area of low temperature biochars, but still dramatically enhanced their ability to sorb aqueous Ni(II). For higher temperature biochars with relatively low surface area, ball milling increased both external and internal surface area. Measurements of pH, zeta potential, stability, and Boehm titration demonstrated that ball milling also added oxygen-containing functional groups (e.g., carboxyl, lactonic, and hydroxyl) to biochar's surface. With these changed, all the BM-biochars showed much better Ni(II) removal efficiency than unmilled biochars. Ball-milled 600 °C bagasse biochar (BMBG600) showed the greatest Ni(II) adsorption capacity (230-650 compared to 26-110 mmol/kg for unmilled biochar) and the adsorption was dosage and pH dependent. Compared with the unmilled biochar, BMBG600 also displayed faster adsorption kinetics, likely due to an increase in rates of intra-particle diffusion in the latter. Experimental and modeling results suggest that the increase in BM-biochar's external and internal surface areas exposed its graphitic structure, thus enhancing Ni(II) adsorption via strong cation-π interaction. In addition, the increase in acidic surface functional groups enhanced Ni(II) adsorption by BM-biochar via electrostatic interaction and surface complexation. Ball milling thus has great potential to increase the efficiency of environmentally friendly biochar for various environmental applications.

Fast environment-friendly ball mill-assisted deep eutectic solvent-based extraction of natural products

A fast environment-friendly extraction method, ball mill-assisted deep eutectic solvent-based extraction, was used for the extraction of natural products from plants. In this study, tanshinones were selected as target compounds to evaluate the efficiency of the developed extraction method. Under the optimized experimental conditions, cryptotanshinone (0.176 mg/g), tanshinone I (0.181 mg/g), and tanshinone II A (0.421 mg/g) were extracted from Salvia miltiorrhiza Bunge, and the developed method was found to be greener, more efficient, and faster than conventional, environmentally harmful extraction methods such as methanol-based ultrasound-assisted extraction and heat reflux extraction. The analytical performances including recovery, reproducibility (RSD, n=5), correlation of determination (r(2)), and the limit of detection, with the ranges of 96.1-103.9%, 1.6-1.9%, 0.9973-0.9984, and 5-8 ng/mL, were respectively obtained. Application of ball mill-assisted deep eutectic solvent-based extraction may fundamentally shape the future development of extraction methods.

A new approach for remediation of As-contaminated soil: ball mill-based technique

In this study, a physical ball mill process instead of chemical extraction using toxic chemical agents was applied to remove arsenic (As) from contaminated soil. A statistical analysis was carried out to establish the optimal conditions for ball mill processing. As a result of the statistical analysis, approximately 70% of As was removed from the soil at the following conditions: 5 min, 1.0 cm, 10 rpm, and 5% of operating time, media size, rotational velocity, and soil loading conditions, respectively. A significant amount of As remained in the grinded fine soil after ball mill processing while more than 90% of soil has the original properties to be reused or recycled. As a result, the ball mill process could remove the metals bound strongly to the surface of soil by the surface grinding, which could be applied as a pretreatment before application of chemical extraction to reduce the load.

Case study of a non-destructive treatment method for the remediation of military structures containing polychlorinated biphenyl contaminated paint

Restricted by federal regulations and limited remediation options, buildings contaminated with paint laden with polychlorinated biphenyls (PCBs) have high costs associated with the disposal of hazardous materials. As opposed to current remediation methods which are often destructive and a risk to the surrounding environment, this study suggests a non-metal treatment system (NMTS) and a bimetallic treatment system (BTS) as versatile remediation options for painted industrial structures including concrete buildings, and metal machine parts. In this field study, four areas of a discontinued Department of Defense site were treated and monitored over 3 weeks. PCB levels in paint and treatment system samples were analyzed through gas chromatography/electron capture detection (GC-ECD). PCB concentrations were reduced by 95 percent on painted concrete and by 60-97 percent on painted metal with the majority of the PCB removal occurring within the first week of application. Post treatment laboratory studies including the utilization of an activated metal treatment system (AMTS) further degraded PCBs in BTS and NMTS by up to 82 percent and 99 percent, respectively, indicating that a two-step remediation option is viable. These findings demonstrate that the NMTS and BTS can be an effective, nondestructive, remediation process for large painted structures, allowing for the reuse or sale of remediated materials that otherwise may have been disposed.

Mechanochemical degradation of hexabromocyclododecane and approaches for the remediation of its contaminated soil

Hexabromocyclododecane (HBCD) has been listed in the Stockholm Convention for elimination due to its persistent and accumulative properties. In consideration of its sound disposal, mechanochemical (MC) method was employed using different co-milling reagents. Fe-Quartz was proven to a good reagent for HBCD destruction achieving both good degradation efficiency and high yield of bromide. The absence of organic matters after MC treatment was demonstrated by thermogravimetry and GC-MS analysis, indicating the complete degradation of HCBD and its conversion into inorganic compounds. No obvious intermediates could be detected due to the swift and spontaneous reaction between HBCD and Fe-Quartz. FTIR and Raman spectra further showed that the organic structures in HBCD were broken down while amorphous and graphite carbon were obtained as another final product besides bromide. After the successful destruction of HBCD, approaches to remediate its contaminated soil were also carried out. Fe-Quartz was also proven to be the best reagent for HBCD degradation in Kaolin, while CaO showed better performance for the remediation of HBCD contaminated Krasnozem. For practical application, preliminary experiments are necessary in order to select a suitable co-milling reagent and a proper milling time depending on the differences in soil properties and HBCD concentration.

Combined pretreatment using alkaline hydrothermal and ball milling to enhance enzymatic hydrolysis of oil palm mesocarp fiber

Hydrothermal pretreatment of oil palm mesocarp fiber was conducted in tube reactor at treatment severity ranges of log Ro = 3.66-4.83 and partial removal of hemicellulose with migration of lignin was obtained. Concerning maximal recovery of glucose and xylose, 1.5% NaOH was impregnated in the system and subsequent ball milling treatment was employed to improve the conversion yield. The effects of combined hydrothermal and ball milling pretreatments were evaluated by chemical composition changes by using FT-IR, WAXD and morphological alterations by SEM. The successful of pretreatments were assessed by the degree of enzymatic digestibility of treated samples. The highest xylose and glucose yields obtained were 63.2% and 97.3% respectively at cellulase loadings of 10 FPU/g-substrate which is the highest conversion from OPMF ever reported.