Removal of As(V) Based on Amino-Group Surface-Functionalized Porous Silicon Derived from Photovoltaic Silicon Cutting Powder

At a Glance

Metadata	Details
Publication Date	2021-07-15
Journal	Coatings
Authors	Kaixin Fu, Yi Li, Xiumin Chen, Wenhui Ma, Ziheng Yang
Institutions	Yunnan University, ARC Centre of Excellence in Advanced Molecular Imaging
Citations	2
Analysis	Full AI Review Included

Technical Documentation & Analysis: Advanced Materials for Environmental Applications

This document analyzes the research paper “Removal of As(V) Based on Amino-Group Surface-Functionalized Porous Silicon Derived from Photovoltaic Silicon Cutting Powder” and connects its findings to the high-performance material solutions offered by 6CCVD (6ccvd.com), an expert provider of MPCVD diamond materials.

Executive Summary

This research successfully demonstrates a sustainable method for creating a highly effective arsenic adsorbent from photovoltaic silicon waste. The key achievements and methodology are summarized below:

Sustainable Material Synthesis: A novel amino-functionalized adsorbent (TEPA-GTS-NPSi) was successfully synthesized from Diamond Wire Saw Silicon Powder (DWSSP) waste via Copper-Assisted Chemical Etching (Cu-ACE).
Rapid Adsorption Kinetics: The material achieved rapid As(V) adsorption equilibrium within 30 minutes at room temperature (25 °C), demonstrating high efficiency for practical applications.
High Adsorption Capacity: A maximum adsorption capacity of 13.2 mg/g was achieved under optimized conditions (pH 7).
Mechanism Confirmation: Adsorption kinetics fit the pseudo-second-order model, indicating chemical adsorption control. The mechanism was confirmed by XPS and DFT analysis to be strong hydrogen bonding interaction between the terminal amino group (-NH₂) and arsenic species (H₂AsO₄^-).
Excellent Reusability: The adsorbent demonstrated good regeneration capability, maintaining 91.8% removal efficiency after five successive cycles using 0.1 mol·L^-1 HCl elution.
Practical Application: The material showed high efficacy (93.71% of theoretical capacity) when treating actual industrial wastewater containing As, Cu, and Zn.

Technical Specifications

The following hard data points were extracted from the experimental results:

Parameter	Value	Unit	Context
Raw Material Source	DWSSP (Kerf Loss)	N/A	Photovoltaic Silicon Cutting Powder
Maximum Adsorption Capacity (q_max)	13.2	mg/g	Optimized pH 7, 25 °C
Adsorption Equilibrium Time	30	min	Time to reach saturation
Minimum Adsorption Limit	3	mg/L	Lowest residual concentration achieved
Optimal Adsorption pH	7	N/A	Stable performance range
Regeneration Efficiency (5 cycles)	91.8	%	Using 0.1 mol·L^-1 HCl desorption agent
Pseudo-Second-Order R²	0.9952	N/A	Indicates chemical adsorption control
Langmuir q_max (Model Fit)	13.8754	mg·g^-1	Confirms monolayer adsorption
DFT Stability Energy (E(2))	40.75	kcal/mol	LP (N1) → BD × (H6-O5) interaction
Grafted GTS Group Mass Loss	7.0	%	Verified by TGA
Grafted TEPA Group Mass Loss	7.1	%	Verified by TGA

Key Methodologies

The synthesis of the Amino-Group Surface-Functionalized Porous Silicon (TEPA-GTS-NPSi) involved a multi-step chemical process:

Raw Material Pre-treatment: Diamond Wire Saw Silicon Powder (DWSSP) was sequentially washed with:
- Ammonia/Hydrogen Peroxide/Deionized Water (2:2:5 volume ratio) to remove organic impurities.
- Hydrochloric Acid/Hydrogen Peroxide/Deionized Water (2:2:5 volume ratio) to remove oxides.
- Final wash with 5% Hydrofluoric Acid (HF) solution.
Nanoporous Silicon (NPSi) Etching (Cu-ACE):
- Copper nanoparticles were chemically deposited on the silicon surface (1 min).
- Etching performed in a mixed solution of HF (40%) and H₂O₂ (5 mM) for 1 hour.
- Residual nano-Cu particles removed using 30% Nitric Acid.
Activation: The etched silicon powder was stirred for 3 hours in a H₂SO₄/H₂O₂ solution (3:1 volume ratio) to increase the density of active Si-OH groups on the surface.
Grafting Step 1 (GTS-NPSi): NPSi, (3-glycidyloxypropyl) trimethoxy-silane (3-GTS), and anhydrous toluene were mixed and stirred for reflux at 60 °C for 24 hours.
Grafting Step 2 (TEPA-GTS-NPSi): The intermediate product (GTS-NPSi) was mixed with tetraethylenepentamine (TEPA) and anhydrous toluene, and stirred for reflux at 60 °C for 24 hours.
Adsorption Studies: Batch experiments were conducted to evaluate the effects of pH (1-8), contact time (0.5-120 min), initial As(V) concentration (10-150 mg/L), and adsorbent dosage (10-35 mg).

6CCVD Solutions & Capabilities

This research highlights the critical need for high-surface-area, chemically stable materials for environmental remediation and sensing. While the paper focuses on recycling silicon waste, 6CCVD specializes in high-purity MPCVD diamond, which offers superior performance and stability for advanced electrochemical and sensing applications, often surpassing the limitations of functionalized silicon substrates.

Applicable Materials

6CCVD provides materials that can replicate or extend this research into high-performance, extreme-environment applications:

Heavy Boron-Doped Diamond (BDD):
- Application: BDD is the gold standard for advanced electrochemical water treatment (e.g., Advanced Oxidation Processes, AOPs) and highly sensitive electrochemical sensing of heavy metals, including arsenic. BDD electrodes offer unparalleled stability across extreme pH ranges and high current densities, where functionalized silicon would degrade.
- 6CCVD Offering: We supply BDD plates and wafers up to 125mm in diameter, suitable for scaling up industrial flow cell designs.
Optical Grade Single Crystal Diamond (SCD):
- Application: Ideal for high-purity optical windows, prisms, and Attenuated Total Reflectance (ATR) elements used in FT-IR or Raman spectroscopy. These materials allow for in-situ analysis of adsorption mechanisms or contaminant detection, offering superior chemical inertness and thermal conductivity compared to silicon.
- 6CCVD Offering: SCD material available in thicknesses from 0.1µm to 500µm, with ultra-low surface roughness (Ra < 1nm).

Customization Potential

To facilitate the integration of high-performance diamond into environmental engineering projects, 6CCVD offers extensive customization services:

Large Area BDD Electrodes: We can supply Polycrystalline Diamond (PCD) and BDD wafers up to 125mm in diameter, enabling the fabrication of large-scale, robust electrodes for industrial wastewater treatment systems.
Custom Metalization: For integrating BDD electrodes into electrochemical reactors or sensor arrays, 6CCVD provides internal metalization capabilities, including Au, Pt, Pd, Ti, W, and Cu layers, ensuring robust electrical contact and chemical resistance.
Precision Processing: We offer precision laser cutting, shaping, and polishing services to meet specific geometric requirements for flow reactors or sensor arrays, achieving surface roughness of Ra < 5nm for inch-size PCD.

Engineering Support

6CCVD’s in-house PhD team specializes in diamond material science and electrochemical applications. We can assist researchers and engineers transitioning from low-cost adsorbents to high-performance BDD electrodes for similar Arsenic Removal and Heavy Metal Sensing projects, ensuring optimal doping levels, surface termination, and integration strategies.

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View Original Abstract

In this study, amino group surface-functionalized porous silicon adsorbent was successfully prepared for the first time using diamond wire saw silicon powder (DWSSP) as raw material through copper-assisted chemical etching (Cu-ACE) and organic functional group grafting. Amino-functionalized porous silicon adsorbent (TEPA-GTS-NPSi) can be used for removing As(V) from water. The properties and mechanism of the new adsorbent were characterized by infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (FE-SEM), Brunauer-Emmett-Teller analysis (BET), and thermogravimetric analysis (TGA). The concentration of metal ions in the solution was determined by inductively coupled plasma spectrometry. Meanwhile, the effects of initial pH, adsorption time, initial concentration and adsorbent dosage on the removal of As(V) in an aqueous solution were studied by intermittent adsorption experiments. The results showed that the adsorption equilibrium could be reached rapidly after 30 min soaking. Under the optimized pH of 7, the maximum adsorption capacity was 13.2 mg/g, and the minimum adsorption limit was 3 mg/L. The adsorbent shows good adsorption performance after five successive regenerated cycles. Based on the density functional theory (DFT) analysis results, the adsorption mechanism is attributed to hydrogen bond interaction between the NH2 group and As(V) ions.

Tech Support

Original Source

DOI: https://doi.org/10.3390/coatings11070850

References

2018 - Solar photovoltaic module production: Environmental footprint, management horizons and investor goodwill [Crossref]
2019 - An additive-free non-metallic energy efficient industrial texturization process for diamond wire sawn multicrystalline silicon wafers [Crossref]
2019 - Effective removal of Cd (II) from aqueous solution based on multifunctional nanoporous silicon derived from solar kerf loss waste [Crossref]
2019 - Kinetic mechanism of aluminum removal from diamond wire saw powder in HCl solution [Crossref]
2019 - Thermodynamic analysis and experimental verification for silicon recovery from the diamond wire saw silicon powder by vacuum carbothermal reduction [Crossref]
2020 - Dissolution and mineralization behavior of metallic impurity content in diamond wire saw silicon powder during acid leaching [Crossref]
2020 - Exploring the potential carcinogenic role of arsenic in gallbladder cancer [Crossref]
2013 - The removal of arsenic from water using natural iron oxide minerals [Crossref]
2016 - Arsenic removal from acidic solutions with biogenic ferric precipitates [Crossref]